U.S. patent application number 15/275041 was filed with the patent office on 2017-03-30 for surface treatment method for nickel-based metallic glasses to reduce nickel release.
The applicant listed for this patent is Glassimetal Technology, Inc.. Invention is credited to Marios D. Demetriou, Glenn Garrett, William L. Johnson, Maximilien Launey, Jong Hyun Na.
Application Number | 20170088933 15/275041 |
Document ID | / |
Family ID | 57137258 |
Filed Date | 2017-03-30 |
United States Patent
Application |
20170088933 |
Kind Code |
A1 |
Launey; Maximilien ; et
al. |
March 30, 2017 |
SURFACE TREATMENT METHOD FOR NICKEL-BASED METALLIC GLASSES TO
REDUCE NICKEL RELEASE
Abstract
Surface treatment methods for Ni-based metallic glasses are
provided that promote passivation and decrease the amount of Ni
released when the Ni-based metallic glass is exposed to a saline
containing environment.
Inventors: |
Launey; Maximilien;
(Pasadena, CA) ; Demetriou; Marios D.; (West
Hollywood, CA) ; Garrett; Glenn; (Pasadena, CA)
; Na; Jong Hyun; (Pasadena, CA) ; Johnson; William
L.; (San Marino, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Glassimetal Technology, Inc. |
Pasadena |
CA |
US |
|
|
Family ID: |
57137258 |
Appl. No.: |
15/275041 |
Filed: |
September 23, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62233488 |
Sep 28, 2015 |
|
|
|
62299366 |
Feb 24, 2016 |
|
|
|
62364063 |
Jul 19, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C23C 22/60 20130101;
C23F 1/00 20130101; C22C 19/05 20130101; C22C 45/04 20130101; C23C
22/58 20130101; C23C 10/26 20130101; C23G 1/20 20130101; C23G 1/10
20130101; C23C 22/24 20130101 |
International
Class: |
C23C 10/26 20060101
C23C010/26; C22C 19/05 20060101 C22C019/05; C22C 45/04 20060101
C22C045/04 |
Claims
1. A method of treating the surface of a Ni-based metallic glass
comprising: immersing at least a portion of the Ni-based metallic
glass in a chemical treatment solution comprising at least one of
an acid solution, a chromate solution, or a molybdate solution to
produce a surface treated portion; and removing the surface treated
portion from the chemical treatment solution; wherein the Ni ion
release rate from the surface treated portion when immersed in a
saline solution for one day is less than 80% of the Ni ion release
rate from an as-cast Ni-based metallic glass having the same
composition and having been immersed in the saline solution for one
day.
2. The method of treating the surface of a Ni-based metallic glass
of claim 1, wherein a duration of immersing in the chemical
treatment solution is at least 1 minute.
3. The method of treating the surface of a Ni-based metallic glass
of claim 1, wherein the temperature of the chemical treatment
solution ranges between 10.degree. C. and 80.degree. C.
4. The method of treating the surface of a Ni-based metallic glass
of claim 1, wherein the chemical treatment solution is a nitric
acid solution, and where the nitric acid concentration is between 5
and 60 volume %.
5. The method of treating the surface of a Ni-based metallic glass
of claim 1, wherein the chemical treatment solution is a sodium
dichromate solution, and where the sodium dichromate concentration
is between 5 and 200 g/L.
6. The method of treating the surface of a Ni-based metallic glass
of claim 1, wherein the chemical treatment solution is a disodium
molybdate solution, and where the disodium molybdate concentration
is between 10 and 100 g/L.
7. The method of treating the surface of a Ni-based metallic glass
of claim 1, where the saline solution has a pH of at least 2.
8. The method of treating the surface of a Ni-based metallic glass
of claim 1, where the saline solution has a concentration of NaCl
of at least 0.1 g/L.
9. The method of treating the surface of a Ni-based metallic glass
of claim 1, where the saline solution is selected from artificial
saliva and artificial perspiration.
10. The method of treating the surface of a Ni-based metallic glass
of claim 9, wherein the Ni ion release rate from the treated
portion of the Ni-based metallic glass when immersed in artificial
perspiration is less than 0.88 .mu.g/cm.sup.2/week.
11. The method of treating the surface of a Ni-based metallic glass
of claim 1, wherein a mass of Ni ion released from the treated
portion of the Ni-based metallic glass when immersed in artificial
saliva for one day is less than 35 .mu.g.
12. A method of treating the surface of a Ni-based metallic glass
comprising: immersing at least a portion of the Ni-based metallic
glass in an acidic first chemical treatment solution; removing the
portion from the acidic first chemical treatment solution;
immersing the portion in a second chemical treatment solution
comprising at least one of a chromate solution or a molybdenum
solution; and removing the portion from the second chemical
treatment solution to produce a surface treated portion; wherein
the Ni ion release rate from the surface treated portion when
immersed in a saline solution for one day is less than 80% of the
Ni ion release rate from an as-cast Ni-based metallic glass having
the same composition and having been immersed in the saline
solution for one day.
13. The method of treating the surface of a Ni-based metallic glass
of claim 12, wherein the acidic first chemical treatment solution
comprises a nitric acid solution having a concentration between 5
and 60 volume %.
14. The method of treating the surface of a Ni-based metallic glass
of claim 12, wherein the second chemical treatment solution
comprises a sodium dichromate solution at concentration between 5
and 200 g/L.
15. The method of treating the surface of a Ni-based metallic glass
of claim 12, wherein the second chemical treatment solution
comprises a disodium molybdate solution at a concentration between
10 and 100 g/L.
16. A passivated Ni-based metallic glass comprising: an inner bulk
material portion, and an outer passive layer portion having an
average combined atomic concentration of Cr and Mo greater than the
average combined atomic concentration of Cr and Mo in the inner
bulk material portion.
17. The passivated Ni-based metallic glass of claim 16, wherein the
outer passive layer is amorphous.
18. The passivated Ni-based metallic glass of claim 16, wherein the
composition of the Ni-based metallic glass is defined by the
formula: Ni.sub.100-a-bX.sub.aZ.sub.b wherein: X is Cr, Mo, Mn, Nb,
Ta, Fe, Co, Cu or combinations thereof; Z is P, B, Si, or
combinations thereof; a is between 5 and 25; and b is between 15
and 25.
19. The passivated Ni-based metallic glass of claim 16, wherein the
average atomic concentration of Cr and Mo in the outer passive
layer is at least 2% higher than the average atomic concentration
of Cr and Mo in the inner bulk material portion.
20. The passivated Ni-based metallic glass of claim 16, wherein the
average atomic concentration of P in the outer passive layer is at
least 5% higher than the average atomic concentration of P in the
inner bulk material portion.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims the benefit under 35 U.S.C.
.sctn.119(e) of U.S. Provisional Patent Application No. 62/233,488,
filed on Sep. 28, 2015, U.S. Provisional Patent Application No.
62/299,366, filed on Feb. 24, 2016 and U.S. Provisional Patent
Application No. 62/364,063, filed on Jul. 19, 2016, entitled
"SURFACE TREATMENT METHOD FOR NICKEL-BASED METALLIC GLASSES TO
REDUCE NICKEL RELEASE," which are incorporated herein by reference
in their entirety.
FIELD
[0002] The disclosure is directed to Ni-based metallic glasses
having passive layers that limit Ni leaching when the metallic
glasses are exposed to a saline containing environment, and surface
treatment methods for Ni-based metallic glasses to promote
formation of such passive layers.
BACKGROUND
[0003] Human tissue contains approximately 0.1 ppm of Ni. Higher Ni
release from materials exposed to biological environments, e.g.
used as implants or placed in the mouth or in contact with the
skin, may generate harmful allergic, toxic, or carcinogenic
reactions. Alloys that are Ni-based (i.e. containing Ni at an
atomic concentration of at least 50%) are therefore of particular
concern, as the Ni release from such materials can be expected to
be rather high. There is a need for a Ni-based metallic glass
capable of resisting Ni leaching when exposed to a biological
environment.
SUMMARY
[0004] The disclosure is directed to surface treatment methods for
Ni-based metallic glasses to reduce the amount of Ni released when
the Ni-based metallic glass is exposed to a saline containing
environment.
[0005] In one embodiment, the disclosure is directed to a surface
treatment method for a Ni-based metallic glass. At least a portion
of a sample of a Ni-based metallic glass is immersed in a chemical
treatment solution to produce a surface treated portion. The
surface treated portion is removed from the chemical treatment
solution to terminate the chemical surface treatment. The chemical
treatment solution comprises at least one of an acid solution, a
chromate solution, and a molybdate solution. The Ni ion release
rate from the surface treated portion of the sample when immersed
in a saline solution for one day is less than 80% of the Ni ion
release rate from an as-cast Ni-based metallic glass sample having
the same composition immersed in the same saline solution for the
same period.
[0006] In another embodiment, the surface treatment method
comprises at least two immersion steps.
[0007] In another embodiment, the surface treatment method
comprises at least two immersion steps, wherein at least one step
comprises immersion in a first chemical treatment solution
comprising an acid and at least one other step comprising immersion
in a second chemical treatment solution comprising a chromate
solution. In such embodiments, each immersion step comprises
immersing at least a portion of the Ni-based metallic glass in a
chemical treatment solution to produce a surface treated portion.
The surface treated portion then is removed from the chemical
treatment solution. In some embodiments, the first chemical
treatment solution is an acid solution while the second chemical
treatment solution is a chromate solution.
[0008] In another embodiment, the second chemical treatment
solution is a sodium dichromate solution.
[0009] In another embodiment, the sodium dichromate concentration
in the sodium dichromate solution is between 5 and 200 g/L.
[0010] In another embodiment, the surface treatment method
comprises at least two immersion steps, wherein at least one step
comprises immersion in a first chemical treatment solution
comprising an acid and at least one other step comprising immersion
in a second chemical treatment solution comprising a molybdate
solution. In such embodiments, each immersion step comprises
immersing at least a portion of the Ni-based metallic glass in a
chemical treatment solution to produce a surface treated portion.
The surface treated portion is then removed from the chemical
treatment solution. In some embodiments, the first chemical
treatment solution is an acid solution while the second chemical
treatment solution is a molybdate solution.
[0011] In another embodiment, the second chemical treatment
solution is a disodium molybdate.
[0012] In another embodiment, the disodium molybdate concentration
in the disodium molybdate solution is between 10 and 100 g/L.
[0013] In another embodiment, the duration of immersion is at least
1 minute.
[0014] In another embodiment, the duration of immersion is at least
10 minutes.
[0015] In another embodiment, the duration of immersion is at least
20 minutes.
[0016] In another embodiment, the duration of immersion is at least
30 minutes.
[0017] In another embodiment, the duration of immersion is at least
60 minutes.
[0018] In another embodiment, the temperature of the chemical
treatment solution ranges between 10 and 80.degree. C.
[0019] In another embodiment, the temperature of the chemical
treatment solution ranges between 20 and 60.degree. C.
[0020] In another embodiment, the temperature of the chemical
treatment solution is in the range of 20 to 30.degree. C.
[0021] In another embodiment, the temperature of the chemical
treatment solution is in the range of 40 to 60.degree. C.
[0022] In another embodiment, the first chemical treatment solution
comprises a nitric acid solution.
[0023] In another embodiment, the nitric acid concentration in the
nitric acid solution is between 5 and 60 vol. %.
[0024] In another embodiment, the nitric acid concentration in the
nitric acid solution is between 20 and 45 vol. %.
[0025] In another embodiment, the nitric acid concentration in the
nitric acid solution is between 15 and 30 vol. %.
[0026] In another embodiment, the nitric acid concentration in the
nitric acid solution is between 20 and 25 vol. %.
[0027] In another embodiment, the disclosure is directed to a
surface treatment method for a Ni-based metallic glass. At least a
portion of a sample of a Ni-based metallic glass is immersed in an
acid solution to promote chemical surface treatment. The sample is
removed from the acid solution to terminate the chemical surface
treatment. Afterwards, the Ni ion release rate from the treated
portion of the sample when immersed in a saline solution for one
day is less than 80% of the Ni ion release rate from an as-cast
Ni-based metallic glass sample having the same composition immersed
in the saline solution for one day.
[0028] In another embodiment, the Ni ion release rate from the
treated portion of the sample when immersed in a saline solution
for one day is less than 60% of the Ni ion release rate from an
as-cast Ni-based metallic glass sample having the same composition
immersed in the saline solution for the one day.
[0029] In another embodiment, the Ni ion release rate from the
treated portion of the sample when immersed in a saline solution
for one day is less than 50% of the Ni ion release rate from an
as-cast Ni-based metallic glass sample having the same composition
when immersed in the saline solution for the one day.
[0030] In another embodiment, the Ni ion release rate from the
treated portion of the sample when immersed in a saline solution
for one day is less than 40% of the Ni ion release rate from an
as-cast Ni-based metallic glass sample having the same composition
immersed in the saline solution for the one day.
[0031] In another embodiment, the Ni ion release rate from the
treated portion of the sample when immersed in a saline solution
for one day is less than 20% of the Ni ion release rate from an
as-cast Ni-based metallic glass sample having the same composition
immersed in the saline solution for the one day.
[0032] In another embodiment, the Ni ion release rate from the
treated portion of the sample when immersed in a saline solution
for 4 days reaches a steady state.
[0033] In another embodiment, the Ni ion release rate from the
treated portion of the sample when immersed in a saline solution
for 2 days reaches a steady state.
[0034] In another embodiment, the Ni ion release rate from the
treated portion of the sample when immersed in a saline solution
for one day reaches a steady state.
[0035] In another embodiment, the Ni ion release rate from the
treated portion of the sample when immersed in a saline solution
for 12 hours reaches a steady state.
[0036] In another embodiment, the Ni ion release rate from the
treated portion of the sample when immersed in a perspiration
solution is less than 0.88 .mu.g/cm.sup.2/week.
[0037] In another embodiment, the Ni ion release rate from the
treated portion of the sample when immersed in artificial
perspiration is less than 0.88 .mu.g/cm.sup.2/week.
[0038] In another embodiment, the Ni ion release rate from the
treated portion of the sample when immersed in a perspiration
solution is less than 0.5 .mu.g/cm.sup.2/week.
[0039] In another embodiment, the Ni ion release rate from the
treated portion of the sample when immersed in a perspiration
solution is less than 0.1 .mu.g/cm.sup.2/week.
[0040] In another embodiment, the Ni ion release rate from the
treated portion of the sample when immersed in a perspiration
solution is less than 0.05 .mu.g/cm.sup.2/week.
[0041] In another embodiment, the Ni ion release rate from the
treated portion of the sample when immersed in a perspiration
solution is less than 0.01 .mu.g/cm.sup.2/week.
[0042] In another embodiment, the mass of Ni ion released from the
treated portion of the sample when immersed in a saline solution
for one day is less than 35 .mu.g.
[0043] In another embodiment, the mass of Ni ion released from the
treated portion of the sample when immersed in a biological
solution for one day is less than 35 .mu.g.
[0044] In another embodiment, the mass of Ni ion released from the
treated portion of the sample when immersed in blood or saliva for
one day is less than 35 .mu.g.
[0045] In another embodiment, the mass of Ni ion released from the
treated portion of the sample when immersed in artificial blood or
artificial saliva for one day is less than 35 .mu.g.
[0046] In another embodiment, the duration of immersion in the
chemical treatment solution is at least 1 minute.
[0047] In another embodiment, the duration of immersion in the
chemical treatment solution is at least 10 minutes.
[0048] In another embodiment, the duration of immersion in the
chemical treatment solution is at least 20 minutes.
[0049] In another embodiment, the duration of immersion in the
chemical treatment solution is at least 30 minutes.
[0050] In another embodiment, the duration of immersion in the
chemical treatment solution is at least 60 minutes.
[0051] In another embodiment, the temperature of the chemical
treatment solution ranges between 10 and 80.degree. C.
[0052] In another embodiment, the temperature of the chemical
treatment solution ranges between 20 and 60.degree. C.
[0053] In another embodiment, the temperature of the chemical
treatment solution is in the range of 20 to 30.degree. C.
[0054] In another embodiment, the temperature of the chemical
treatment solution is in the range of 40 to 60.degree. C.
[0055] In another embodiment, the duration of immersion in the acid
solution is at least 1 minute.
[0056] In another embodiment, the duration of immersion in the acid
solution is at least 10 minutes.
[0057] In another embodiment, the duration of immersion in the acid
solution is at least 20 minutes.
[0058] In another embodiment, the duration of immersion in the acid
solution is at least 30 minutes.
[0059] In another embodiment, the duration of immersion in the acid
solution is at least 60 minutes.
[0060] In another embodiment, the temperature of the acid solution
ranges between 10 and 80.degree. C.
[0061] In another embodiment, the temperature of the acid solution
ranges between 20 and 60.degree. C.
[0062] In another embodiment, the temperature of the acid solution
is in the range of 20 to 30.degree. C.
[0063] In another embodiment, the temperature of the acid solution
is in the range of 40 to 60.degree. C.
[0064] In another embodiment, the acid solution comprises nitric
acid.
[0065] In another embodiment, the acid solution comprises nitric
acid, where the nitric acid concentration is between 5 and 60 vol.
%.
[0066] In another embodiment, the acid solution comprises nitric
acid, where the nitric acid concentration is between 20 and 45 vol.
%.
[0067] In another embodiment, the acid solution comprises nitric
acid, where the nitric acid concentration is between 15 and 30 vol.
%.
[0068] In another embodiment, the acid solution comprises nitric
acid, where the nitric acid concentration is between 20 and 25 vol.
%.
[0069] In another embodiment, the chemical treatment solution
comprises a chromate solution.
[0070] In another embodiment, the chemical treatment solution
comprises sodium dichromate.
[0071] In another embodiment, the chemical treatment solution
comprises sodium dichromate, where the sodium dichromate
concentration is between 5 and 200 g/L.
[0072] In another embodiment, the chemical treatment solution
comprises sodium dichromate, where the sodium dichromate
concentration is between 10 and 100 g/L.
[0073] In another embodiment, the chemical treatment solution
comprises a molybdate solution.
[0074] In another embodiment, the chemical treatment solution
comprises disodium molybdate.
[0075] In another embodiment, the chemical treatment solution
comprises disodium molybdate, where the disodium molybdate
concentration is between 5 and 200 g/L.
[0076] In another embodiment, the chemical treatment solution
comprises disodium molybdate, where the disodium molybdate
concentration is between 10 and 100 g/L.
[0077] In another embodiment, the saline solution has a pH of at
least 2.
[0078] In another embodiment, the saline solution has a pH of at
least 4.
[0079] In another embodiment, the saline solution has a pH of at
least 6.
[0080] In another embodiment, the saline solution has a
concentration of NaCl of at least 0.1 g/L.
[0081] In another embodiment, the saline solution has a
concentration of NaCl of at least 0.25 g/L.
[0082] In another embodiment, the saline solution has a
concentration of NaCl of at least 1 g/L.
[0083] In another embodiment, the saline solution has a
concentration of NaCl of at least 2 g/L.
[0084] In another embodiment, the saline solution has a
concentration of NaCl of at least 5 g/L.
[0085] In another embodiment, the saline solution is a biological
solution.
[0086] In another embodiment, the saline solution is saliva.
[0087] In another embodiment, the saline solution is
perspiration.
[0088] In another embodiment, the saline solution is blood.
[0089] In another embodiment, the saline solution is a simulated
body fluid.
[0090] In another embodiment, the saline solution is artificial
saliva.
[0091] In another embodiment, the saline solution is artificial
perspiration.
[0092] In another embodiment, the saline solution is artificial
blood.
[0093] In another embodiment, the saline solution is sea water.
[0094] In another embodiment, the saline solution is simulated sea
water.
[0095] In another embodiment, the metal moiety of the Ni-based
metallic glass comprises at least one of Cr, Mo, Mn, Nb, Ta, Fe,
Co, and Cu in its metal moiety.
[0096] In another embodiment, the metal moiety of the Ni-based
metallic glass comprises at least Cr.
[0097] In another embodiment, the metal moiety of the Ni-based
metallic glass comprises at least Mo.
[0098] In another embodiment, the metalloid moiety of the Ni-based
metallic glass comprises at least one of P, B, and Si.
[0099] In another embodiment, the metalloid moiety of the Ni-based
metallic glass comprises P and B.
[0100] In another embodiment, the metalloid moiety of the Ni-based
metallic glass comprises P and Si.
[0101] In another embodiment, the metalloid moiety of the Ni-based
metallic glass comprises Si and B.
[0102] In another embodiment, the Ni-based metallic glass comprises
Cr and P.
[0103] In another embodiment, the Ni-based metallic glass is free
of Ti.
[0104] In another embodiment, the passivated Ni-based metallic
glass has a composition according to the following formula
(subscripts denote atomic percent):
Ni.sub.100-a-bX.sub.aZ.sub.b
where:
[0105] X is Cr, Mo, Mn, Nb, Ta, Fe, Co, Cu or combinations
thereof;
[0106] Z is P, B, Si, or combinations thereof;
[0107] a is between 5 and 25; and
[0108] b is between 15 and 25.
[0109] In another embodiment, X is Cr and at least one of Nb and
Ta, and Z is P and B.
[0110] In another embodiment, X is Cr and Nb, and Z is P and
Si.
[0111] In another embodiment, X is Mo and at least one of Nb and
Mn, and Z is P and B.
[0112] In another embodiment, X is Mo and at least one of Nb and
Mn, and Z is P and Si.
[0113] In another embodiment, the passive layer has an amorphous
structure.
[0114] In another embodiment, the passive layer of a
surface-treated sample is thicker compared to the passive layer of
an untreated sample.
[0115] In another embodiment the Ni-based metallic glass and/or
passivated Ni-based metallic glass comprises Cr and P, and the
passive layer of the surface-treated sample comprises O, P, and
Cr.
[0116] In another embodiment the Ni-based metallic glass and/or
passivated Ni-based metallic glass comprises Mo and P, and the
passive layer of the surface-treated sample comprises O, P, and
Mo.
[0117] In another embodiment, the passive layer of the
surface-treated sample is poor in Ni.
[0118] In another embodiment, the average concentration of O within
the passive layer of the surface-treated sample of a Ni-based
metallic glass is higher than the concentration of O in an
untreated sample.
[0119] In another embodiment, the average concentration of Ni
within the passive layer of the surface treated sample of a
Ni-based metallic glass and/or passivated Ni-based metallic glass
is lower than the concentration of Ni in an untreated sample.
[0120] In another embodiment, the average concentration of P within
the passive layer of the surface-treated sample of a Ni-based
metallic glass and/or passivated Ni-based metallic glass comprising
P is higher than the concentration of P in an untreated sample.
[0121] In another embodiment, the average concentration of Cr
within the passive layer of the surface-treated sample of a
Ni-based metallic glass and/or passivated Ni-based metallic glass
comprising Cr is higher than the concentration of Cr in an
untreated sample.
[0122] In another embodiment, the average concentration of O within
the passive layer of the surface-treated sample of a Ni-based
metallic glass and/or passivated Ni-based metallic glass comprising
Cr and P is at least 5% higher than the concentration of O in an
untreated sample.
[0123] In another embodiment, the average concentration of O within
the passive layer of the surface-treated sample of a Ni-based
metallic glass and/or passivated Ni-based metallic glass comprising
Cr and P is at least 10% higher than the concentration of O in an
untreated sample.
[0124] In another embodiment, the average concentration of O within
the passive layer of the surface-treated sample of a Ni-based
metallic glass and/or passivated Ni-based metallic glass comprising
Cr and P is at least 20% higher than the concentration of O in an
untreated sample.
[0125] In another embodiment, the average concentration of P within
the passive layer of the surface-treated sample of a passivated
Ni-based metallic glass comprising Cr and P is at least 5% higher
than the concentration of P in an untreated sample.
[0126] In another embodiment, the average concentration of P within
the passive layer of the surface-treated sample of a passivated
Ni-based metallic glass comprising Cr and P is at least 10% higher
than the concentration of P in an untreated sample.
[0127] In another embodiment, the average concentration of P within
the passive layer of the surface-treated sample of a passivated
Ni-based metallic glass comprising Cr and P is at least 20% higher
than the concentration of P in an untreated sample.
[0128] In another embodiment, the average concentration of Cr
within the passive layer of the surface-treated sample of a
Ni-based metallic glass and/or passivated Ni-based metallic glass
comprising Cr and P is at least 5% higher than the concentration of
Cr in an untreated sample.
[0129] In another embodiment, the average concentration of Cr
within the passive layer of the surface-treated sample of a
Ni-based metallic glass and/or passivated Ni-based metallic glass
comprising Cr and P is at least 10% higher than the concentration
of Cr in an untreated sample.
[0130] In another embodiment, the average concentration of Cr
within the passive layer of the surface-treated sample of a
Ni-based metallic glass and/or passivated Ni-based metallic glass
comprising Cr and P is at least 20% higher than the concentration
of Cr in an untreated sample.
[0131] In another embodiment, the average concentration of Ni
within the passive layer of the surface-treated sample of a
Ni-based metallic glass and/or passivated Ni-based metallic glass
comprising Cr and P is at least 5% lower than the concentration of
Ni in an untreated sample.
[0132] In another embodiment, the average concentration of Ni
within the passive layer of the surface-treated sample of a
Ni-based metallic glass and/or passivated Ni-based metallic glass
comprising Cr and P is at least 10% lower than the concentration of
Ni in an untreated sample.
[0133] In another embodiment, the average concentration of Ni
within the passive layer of the surface-treated sample of a
Ni-based metallic glass and/or passivated Ni-based metallic glass
comprising Cr and P is at least 20% lower than the concentration of
Ni in an untreated sample.
[0134] In other embodiments, the passive layer of the
surface-treated sample of a Ni-based metallic glass and/or
passivated Ni-based metallic glass comprising Cr and P is thicker
than the passive layer of an untreated sample.
[0135] In other embodiments, the passive layer of the
surface-treated sample of a Ni-based metallic glass and/or
passivated Ni-based metallic glass comprising Cr and P is at least
5% thicker than the passive layer of an untreated sample.
[0136] In another embodiment, the average concentration of Ni
within the passive layer of the surface-treated sample of a
Ni-based metallic glass and/or passivated Ni-based metallic glass
comprising Cr and P is at least 10% lower than the concentration of
Ni in an untreated sample.
[0137] In another embodiment, the average concentration of Ni
within the passive layer of the surface-treated sample of a
Ni-based metallic glass and/or passivated Ni-based metallic glass
comprising Cr and P is at least 20% lower than the concentration of
Ni in an untreated sample.
[0138] In another embodiment, the average concentration of O within
the passive layer of the surface-treated sample of a Ni-based
metallic glass and/or passivated Ni-based metallic glass comprising
Cr and P that has been surface treated in a nitric acid solution of
concentration of at least 15 vol. % for at least 30 minutes is at
least 5% higher than the concentration of O in an untreated
sample.
[0139] In another embodiment, the average concentration of O within
the passive layer of the surface-treated sample of a Ni-based
metallic glass and/or passivated Ni-based metallic glass comprising
Cr and P that has been surface treated in a nitric acid solution of
concentration of at least 15 vol. % for at least 30 minutes is at
least 50% higher than the concentration of O in an untreated
sample.
[0140] In another embodiment, the average concentration of P within
the passive layer of the surface-treated sample of a passivated
Ni-based metallic glass comprising Cr and P that has been surface
treated in a nitric acid solution of concentration of at least 15
vol. % for at least 30 minutes is at least 10% higher than the
concentration of P in an untreated sample.
[0141] In another embodiment, the average concentration of P within
the passive layer of the surface-treated sample of a passivated
Ni-based metallic glass comprising Cr and P that has been surface
treated in a nitric acid solution of concentration of at least 15
vol. % for at least 30 minutes is at least 20% higher than the
concentration of P in an untreated sample.
[0142] In another embodiment, the average concentration of Cr
within the passive layer of the surface-treated sample of a
Ni-based metallic glass and/or passivated Ni-based metallic glass
comprising Cr and P that has been surface treated in a nitric acid
solution of concentration of at least 15 vol. % for at least 30
minutes is at least 15% higher than the concentration of Cr in an
untreated sample.
[0143] In another embodiment, the average concentration of Cr
within the passive layer of the surface-treated sample of a
Ni-based metallic glass and/or passivated Ni-based metallic glass
comprising Cr and P that has been surface treated in a nitric acid
solution of concentration of at least 15 vol. % for at least 30
minutes is at least 15% higher than the concentration of Cr in an
untreated sample.
[0144] In another embodiment, the average concentration of Ni
within the passive layer of the surface-treated sample of a
Ni-based metallic glass and/or passivated Ni-based metallic glass
comprising Cr and P that has been surface treated in a nitric acid
solution of concentration of at least 15 vol. % for at least 30
minutes is at least 5% lower than the concentration of Ni in an
untreated sample.
[0145] In another embodiment, the average concentration of Ni
within the passive layer of the surface-treated sample of a
Ni-based metallic glass and/or passivated Ni-based metallic glass
comprising Cr and P that has been surface treated in a nitric acid
solution of concentration of at least 15 vol. % for at least 30
minutes is at least 10% lower than the concentration of Ni in an
untreated sample.
[0146] In other embodiments, the passive layer of the
surface-treated sample of a Ni-based metallic glass and/or
passivated Ni-based metallic glass comprising Cr and P that has
been surface treated in a nitric acid solution of concentration of
at least 15 vol. % for at least 30 minutes is thicker than the
passive layer of an untreated sample.
[0147] In other embodiments, the passive layer of the
surface-treated sample of a Ni-based metallic glass and/or
passivated Ni-based metallic glass comprising Cr and P that has
been surface treated in a nitric acid solution of concentration of
at least 15 vol. % for at least 30 minutes is at least 5% thicker
than the passive layer of an untreated sample.
[0148] In other embodiments, the passive layer of the
surface-treated sample of a Ni-based metallic glass and/or
passivated Ni-based metallic glass comprising Cr and P that has
been surface treated in a nitric acid solution of concentration of
at least 15 vol. % for at least 30 minutes is at least 10% thicker
than the passive layer of an untreated sample.
[0149] In other embodiments, the passive layer of the
surface-treated sample of a Ni-based metallic glass and/or
passivated Ni-based metallic glass comprising Cr and P that has
been surface treated in a nitric acid solution of concentration of
at least 15 vol. % for at least 30 minutes is at least 25% thicker
than the passive layer of an untreated sample.
[0150] The disclosure is also directed to a Ni-based metallic glass
and/or passivated Ni-based metallic glass comprising an inner bulk
material portion, and an outer passive layer portion. The Ni-based
metallic glass and/or passivated Ni-based metallic glass comprise
at least one of Cr and Mo. The average atomic concentration of Cr
and/or Mo within the passive layer portion is higher than the
respective concentrations in the inner bulk material portion.
[0151] In another embodiment, the average atomic concentration of
Cr and/or Mo within the passive layer is at least 2% higher than
the respective concentrations in the inner bulk material
portion.
[0152] In another embodiment, the average atomic concentration of
Cr and/or Mo within the passive layer is at least 5% higher than
the respective concentrations in the inner bulk material
portion.
[0153] In another embodiment, the average atomic concentration of
Cr and/or Mo within the passive layer is at least 10% higher than
the respective concentrations in the inner bulk material
portion.
[0154] In another embodiment, the average atomic concentration of
Cr and/or Mo within the passive layer is at least 20% higher than
the respective concentrations in the inner bulk material
portion.
[0155] The disclosure is also directed to a Ni-based metallic glass
and/or passivated Ni-based metallic glass comprising an inner bulk
material portion, and an outer passive layer portion. The Ni-based
metallic glass and/or passivated Ni-based metallic glass comprise
P. The average atomic concentration of P within the passive layer
portion is higher than the P concentration in the inner bulk
material portion. In some variations, the inner bulk material
portion that comprises Cr and P and an outer passive layer portion
that comprises Cr, P, and O.
[0156] In some variations, the inner bulk material portion
comprises Mo and P and the outer passive layer comprises Mo, P, and
O. In some variations, the average atomic concentration of Cr and
Mo in the outer passive layer is at least 2% higher than the
average atomic concentration of Cr and Mo in the inner bulk
material portion. In some variations, the average atomic
concentration of P in the outer passive layer is at least 5% higher
than the average atomic concentration of P in the inner bulk
material portion.
[0157] In another embodiment, the average atomic concentration of P
within the passive layer is at least 5% higher than the P
concentration in the inner bulk material portion.
[0158] In another embodiment, the average atomic concentration of P
within the passive layer is at least 10% higher than the P
concentration in the inner bulk material portion.
[0159] In another embodiment, the average atomic concentration of P
within the passive layer is at least 20% higher than the respective
concentration in the inner bulk material portion.
[0160] In another embodiment, the average atomic concentration of P
within the passive layer is at least 30% higher than the respective
concentration in the inner bulk material portion.
[0161] The disclosure is also directed to an article of a
passivated Ni-based metallic glass.
BRIEF DESCRIPTION OF THE DRAWINGS
[0162] FIG. 1 provides a plot showing the effect of surface
treatment in a Nitric acid solution on the Nickel-ion release rate
of Ni.sub.71.4Cr.sub.5.52Nb.sub.3.38P.sub.16.67B.sub.3.03 metallic
glass in a PBS (Phosphate Buffered Solution) solution in accordance
with embodiments.
[0163] FIG. 2 provides a plot showing the effect of surface
treatment in a Citric acid solution on the Nickel-ion release rate
of Ni.sub.71.4Cr.sub.5.52Nb.sub.3.38P.sub.16.67B.sub.3.03 metallic
glass in a PBS (Phosphate Buffered Solution) solution in accordance
with embodiments.
[0164] FIG. 3 provides a plot showing the effect of surface
treatment in a Nitric acid solution on the Nickel-ion release rate
of
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass in a PBS (Phosphate Buffered Solution) solution in
accordance with embodiments.
[0165] FIG. 4 provides a plot showing the effect of surface
treatment on the weekly Nickel-ion release rate of
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass in an artificial perspiration solution.
[0166] FIG. 5 provides a plot of depth profile up to 200 angstrom
for the concentration of Oxygen on the surfaces of an as-polished
sample and samples surface treated in nitric acid solutions at
various acid concentrations, as detected by XPS in accordance with
embodiments.
[0167] FIG. 6 provides a plot of depth profile up to 200 angstrom
for the concentration of Phosphorus/Boron on the surfaces of an
as-polished and samples surface treated in nitric acid solutions at
various acid concentrations, as detected by XPS in accordance with
embodiments.
[0168] FIG. 7 provides a plot of depth profile up to 200 angstrom
for the concentration of Chromium on the surfaces of an as-polished
sample and samples surface treated in nitric acid solutions at
various acid concentrations, as detected by XPS in accordance with
embodiments.
[0169] FIG. 8 provides a plot of depth profile up to 200 angstrom
for the concentration of Niobium on the surfaces of an as-polished
sample and samples surface treated in nitric acid solutions at
various acid concentrations, as detected by XPS in accordance with
embodiments.
[0170] FIG. 9 provides a plot of depth profile up to 200 angstrom
for the concentration of Nickel on the surfaces of an as-polished
sample and samples surface treated in nitric acid solutions at
various acid concentrations, as detected by XPS in accordance with
embodiments.
[0171] FIG. 10 provides a plot of depth profile up to 200 angstrom
for the concentration of Oxygen on the surfaces of an as-polished
sample and a sample surface treated in a 20 vol. % nitric acid
solution, as detected by SIMS in accordance with embodiments. The
insets provide plots of depth profile up to 60 angstrom for the
detected Oxygen, and the regions for the "organic layer," "passive
layer," and "bulk material" are designated by arrows. The "bulk
material" designation in the figures refers to the inner bulk
material portion.
[0172] FIG. 11 provides a plot of depth profile up to 200 angstrom
for the concentration of Phosphorus on the surfaces of an
as-polished sample and a sample surface treated in a 20 vol. %
nitric acid solution, as detected by SIMS in accordance with
embodiments. The insets provide plots of depth profile up to 60
angstrom for the detected Phosphorus, and the regions for the
"organic layer," "passive layer," and "bulk material" are
designated by arrows.
[0173] FIG. 12 provides a plot of depth profile up to 200 angstrom
for the concentration of Chromium on the surfaces of an as-polished
sample and a sample surface treated in a 20 vol. % nitric acid
solution, as detected by SIMS in accordance with embodiments. The
insets provide plots of depth profile up to 60 angstrom for the
detected Chromium, and the regions for the "organic layer,"
"passive layer," and "bulk material" are designated by arrows.
[0174] FIG. 13 provides a plot of depth profile up to 200 angstrom
for the concentration of Niobium on the surfaces of an as-polished
sample and a sample surface treated in a 20 vol. % nitric acid
solution, as detected by SIMS in accordance with embodiments. The
insets provide plots of depth profile up to 60 angstrom for the
detected Niobium, and the regions for the "organic layer," "passive
layer," and "bulk material" are designated by arrows.
[0175] FIG. 14 provides a plot of depth profile up to 200 angstrom
for the concentration of Boron on the surfaces of an as-polished
sample and a sample surface treated in a 20 vol. % nitric acid
solution, as detected by SIMS in accordance with embodiments. The
insets provide plots of depth profile up to 60 angstrom for the
detected Boron, and the regions for the "organic layer," "passive
layer," and "bulk material" are designated by arrows.
[0176] FIG. 15 provides a plot of depth profile up to 200 angstrom
for the concentration of Silicon on the surfaces of an as-polished
sample and a sample surface treated in a 20 vol. % nitric acid
solution, as detected by SIMS in accordance with embodiments. The
insets provide plots of depth profile up to 60 angstrom for the
detected Silicon, and the regions for the "organic layer," "passive
layer," and "bulk material" are designated by arrows.
[0177] FIG. 16 provides a plot of depth profile up to 200 angstrom
for the concentration of Nickel on the surfaces of an as-polished
sample and a sample surface treated in a 20 vol. % nitric acid
solution, as detected by SIMS in accordance with embodiments. The
insets provide plots of depth profile up to 60 angstrom for the
detected Nickel, and the regions for the "organic layer," "passive
layer," and "bulk material" are designated by arrows.
[0178] FIG. 17 provides a plot of depth profile up to 350 angstrom
for the concentration of Oxygen on the surfaces of an as-polished
sample and a sample surface treated in a 50 g/L sodium dichromate
solution, as detected by SIMS in accordance with embodiments. The
insets provide plots of depth profile up to 100 angstrom for the
detected Oxygen, and the "passive layer" region for each sample is
designated by an arrow (solid arrow designates the "passive layer"
region of the as-polished sample, while broken arrow designates the
"passive layer" region of the surface treated sample).
[0179] FIG. 18 provides a plot of depth profile up to 350 angstrom
for the concentration of Phosphorus on the surfaces of an
as-polished sample and a sample surface treated in a 50 g/L sodium
dichromate solution, as detected by SIMS in accordance with
embodiments. The insets provide plots of depth profile up to 100
angstrom for the detected Phosphorus, and the "passive layer"
region for each sample is designated by an arrow (solid arrow
designates the "passive layer" region of the as-polished sample,
while broken arrow designates the "passive layer" region of the
surface treated sample).
[0180] FIG. 19 provides a plot of depth profile up to 350 angstrom
for the concentration of Chromium on the surfaces of an as-polished
sample and a sample surface treated in a 50 g/L sodium dichromate
solution, as detected by SIMS in accordance with embodiments. The
insets provide plots of depth profile up to 100 angstrom for the
detected Chromium, and the "passive layer" region for each sample
is designated by an arrow (solid arrow designates the "passive
layer" region of the as-polished sample, while broken arrow
designates the "passive layer" region of the surface treated
sample).
[0181] FIG. 20 provides a plot of depth profile up to 350 angstrom
for the concentration of Niobium on the surfaces of an as-polished
sample and a sample surface treated in a 50 g/L sodium dichromate
solution, as detected by SIMS in accordance with embodiments. The
insets provide plots of depth profile up to 100 angstrom for the
detected Niobium, and the "passive layer" region for each sample is
designated by an arrow (solid arrow designates the "passive layer"
region of the as-polished sample, while broken arrow designates the
"passive layer" region of the surface treated sample).
[0182] FIG. 21 provides a plot of depth profile up to 350 angstrom
for the concentration of Boron on the surfaces of an as-polished
sample and a sample surface treated in a 50 g/L sodium dichromate
solution, as detected by SIMS in accordance with embodiments. The
insets provide plots of depth profile up to 100 angstrom for the
detected Boron, and the "passive layer" region for each sample is
designated by an arrow (solid arrow designates the "passive layer"
region of the as-polished sample, while broken arrow designates the
"passive layer" region of the surface treated sample).
[0183] FIG. 22 provides a plot of depth profile up to 350 angstrom
for the concentration of Silicon on the surfaces of an as-polished
sample and a sample surface treated in a 50 g/L sodium dichromate
solution, as detected by SIMS in accordance with embodiments. The
insets provide plots of depth profile up to 100 angstrom for the
detected Silicon, and the "passive layer" region for each sample is
designated by an arrow (solid arrow designates the "passive layer"
region of the as-polished sample, while broken arrow designates the
"passive layer" region of the surface treated sample).
[0184] FIG. 23 provides a plot of depth profile up to 350 angstrom
for the concentration of Nickel on the surfaces of an as-polished
sample and a sample surface treated in a 50 g/L sodium dichromate
solution, as detected by SIMS in accordance with embodiments. The
insets provide plots of depth profile up to 100 angstrom for the
detected Nickel, and the "passive layer" region for each sample is
designated by an arrow (solid arrow designates the "passive layer"
region of the as-polished sample, while broken arrow designates the
"passive layer" region of the surface treated sample).
[0185] FIG. 24 provides a plot of depth profile up to 200 angstrom
for the concentration of Oxygen on the surfaces of an as-polished
sample and a sample surface treated by a two-step chemical solution
treatment (the first solution comprises 20 volume % nitric acid
combined with 25 g/L sodium dichromate, and the second solution
comprises 50 g/L sodium dichromate), as detected by SIMS in
accordance with embodiments. The insets provide plots of depth
profile up to 60 angstrom for the detected Oxygen, and the "passive
layer" region for each sample is designated by an arrow (solid
arrow designates the "passive layer" region of the as-polished
sample, while broken arrow designates the "passive layer" region of
the surface treated sample).
[0186] FIG. 25 provides a plot of depth profile up to 200 angstrom
for the concentration of Phosphorus on the surfaces of an
as-polished sample and a sample surface treated by a two-step
chemical solution treatment (the first solution comprises 20 volume
% nitric acid combined with 25 g/L sodium dichromate, and the
second solution comprises 50 g/L sodium dichromate), as detected by
SIMS in accordance with embodiments. The insets provide plots of
depth profile up to 60 angstrom for the detected Phosphorus, and
the "passive layer" region for each sample is designated by an
arrow (solid arrow designates the "passive layer" region of the
as-polished sample, while broken arrow designates the "passive
layer" region of the surface treated sample).
[0187] FIG. 26 provides a plot of depth profile up to 200 angstrom
for the concentration of Chromium on the surfaces of an as-polished
sample and a sample surface treated by a two-step chemical solution
treatment (the first solution comprises 20 volume % nitric acid
combined with 25 g/L sodium dichromate, and the second solution
comprises 50 g/L sodium dichromate), as detected by SIMS in
accordance with embodiments. The insets provide plots of depth
profile up to 60 angstrom for the detected Chromium, and the
"passive layer" region for each sample is designated by an arrow
(solid arrow designates the "passive layer" region of the
as-polished sample, while broken arrow designates the "passive
layer" region of the surface treated sample).
[0188] FIG. 27 provides a plot of depth profile up to 200 angstrom
for the concentration of Niobium on the surfaces of an as-polished
sample and a sample surface treated by a two-step chemical solution
treatment (the first solution comprises 20 volume % nitric acid
combined with 25 g/L sodium dichromate, and the second solution
comprises 50 g/L sodium dichromate), as detected by SIMS in
accordance with embodiments. The insets provide plots of depth
profile up to 60 angstrom for the detected Niobium, and the
"passive layer" region for each sample is designated by an arrow
(solid arrow designates the "passive layer" region of the
as-polished sample, while broken arrow designates the "passive
layer" region of the surface treated sample).
[0189] FIG. 28 provides a plot of depth profile up to 200 angstrom
for the concentration of Boron on the surfaces of an as-polished
sample and a sample surface treated by a two-step chemical solution
treatment (the first solution comprises 20 volume % nitric acid
combined with 25 g/L sodium dichromate, and the second solution
comprises 50 g/L sodium dichromate), as detected by SIMS in
accordance with embodiments. The insets provide plots of depth
profile up to 60 angstrom for the detected Boron, and the "passive
layer" region for each sample is designated by an arrow (solid
arrow designates the "passive layer" region of the as-polished
sample, while broken arrow designates the "passive layer" region of
the surface treated sample).
[0190] FIG. 29 provides a plot of depth profile up to 200 angstrom
for the concentration of Silicon on the surfaces of an as-polished
sample and a sample surface treated by a two-step chemical solution
treatment (the first solution comprises 20 volume % nitric acid
combined with 25 g/L sodium dichromate, and the second solution
comprises 50 g/L sodium dichromate), as detected by SIMS in
accordance with embodiments. The insets provide plots of depth
profile up to 60 angstrom for the detected Silicon, and the
"passive layer" region for each sample is designated by an arrow
(solid arrow designates the "passive layer" region of the
as-polished sample, while broken arrow designates the "passive
layer" region of the surface treated sample).
[0191] FIG. 30 provides a plot of depth profile up to 200 angstrom
for the concentration of Nickel on the surfaces of an as-polished
sample and a sample surface treated by a two-step chemical solution
treatment (the first solution comprises 20 volume % nitric acid
combined with 25 g/L sodium dichromate, and the second solution
comprises 50 g/L sodium dichromate), as detected by SIMS in
accordance with embodiments. The insets provide plots of depth
profile up to 60 angstrom for the detected Nickel, and the "passive
layer" region for each sample is designated by an arrow (solid
arrow designates the "passive layer" region of the as-polished
sample, while broken arrow designates the "passive layer" region of
the surface treated sample).
[0192] FIG. 31 presents a plot of the logarithm of the Ni ion
release rate in units of .mu.g/cm.sup.2/week against the average
atomic concentration of Cr in the passive layer in units of atomic
percent. The line is a power-law fit through the data.
DETAILED DESCRIPTION
[0193] The disclosure is directed to methods of chemical surface
treatment for Ni-based metallic glasses to reduce the amount of Ni
release when the metallic glass is exposed to a saline containing
environment. Embodiments of the chemical surface treatment methods
improve the corrosion resistance of Ni-based metallic glasses in
biological, physiological, and other saline-containing environments
by protecting the material with a stable passive layer that acts as
a barrier coating against Ni ion release.
[0194] Chemical surface treatments are generally applied in order
to encourage passivation of a material by promoting surface
oxidation and by dissolving foreign materials that might be present
on the surface of the material from previous operations. Rapid
passivation of the material will provide corrosion resistance when
exposed to a corrosive environment, and prevent leaching of the
various elemental constituents of the material into the corrosive
environment.
[0195] The surface oxide layer increases the stability of the
surface layers by protecting the bulk material from corrosion, and
creates a physical and chemical barrier against Ni oxidation by
modifying the oxidation pathways of Ni.
[0196] The applicability of a surface treatment to promote rapid
passivation by surface oxidation depends strongly on the chemistry
between the elemental constituents of the alloy and the chemical
treatment solution, as well as on the chemistry between the formed
surface oxide layer and the corrosive environment, making it
difficult to predict the applicability of a surface treatment
between different classes of materials. For example, chemical
surface treatment for chrome containing stainless steel has been
well studied, and it has been determined that the type and nature
of surface treatment that can promote passivation depends on
factors such as the chrome content and the physical characteristics
of the stainless steel (such as machinability). Moreover, improper
chemical treatment can actually induce corrosion in the sample.
[0197] The applicability of the surface treatment also depends on
the atomic structure of the material, as well as that of the
surface oxide layer. Again, using the example of chrome containing
stainless steel as a benchmark, it has been found that the type of
chemical treatment that promotes passivation changes depending on
the crystal structure of the stainless steel. For example,
stainless steels with austenitic, ferritic, or martensitic crystal
structures require very specific chemical treatment processes (e.g.
solution chemistry, additives, solution temperature, etc.) to
successfully promote passivation. In certain instances, certain
chemical treatments that work for some crystal structures don't
work for others (e.g. citric acid works for ferritic type Chrome
Core 18FM but not nitric acid; by contrast, nitric acid works for
ferritic types 430F and 430FR but not citric acid) (DeBold, Terry
A. & Martin, James W. "How To Passivate Stainless Steel Parts"
Modern Machine Shop, Oct. 1, 2003). Moreover, inappropriate
chemical treatment of stainless steels may cause "flash attacks",
where instead of passivating the material by obtaining the desired
oxide film, which typically appears as a shiny and clean surface
layer, a heavily etched or darkened surface layer is produced. This
causes degradation of the surface rather than passivation, and
generally leads to higher corrosion rates.
[0198] Because the promotion of passivation depends intimately on
the crystalline structure of the sample and the chemistry occurring
between the chemical treatment solution and the sample, this
unpredictability is heightened when chemical surface treatments are
attempted on a non-crystalline material, such as a metallic glass
(i.e. an amorphous metal). In one example, discussed in U.S. Pat.
Pub. No. 2009/0014096, samples of Zr--Ti based amorphous alloys
containing one or more of Ni, Cu, Co, Fe, Cr and Be were tested for
corrosion resistance in acid baths. The studies showed that, rather
than promoting passivation, many of these materials corroded very
rapidly in the acidic environment. Moreover, the publication states
that exposure to acidic environments for Ni and Cu alloys
particularly should be avoided. Indeed, amorphous alloys containing
these elements have been shown to dissolve almost immediately when
exposed to an acidic environment. (U.S. Pat. Pub. No. 2009/0014096,
the disclosure of which is incorporated herein by reference.) To
date, passivation of a material that has an amorphous atomic
structure, and specifically a Ni-based metallic glass, by a
chemical surface treatment has not been implemented. Accordingly,
chemical surface treatment methods for promoting the passivation of
Ni-based metallic glasses need to be developed.
[0199] Many embodiments are directed to methods of surface
treatment for Ni-based alloys, i.e. to alloys that comprise Ni at
an atomic fraction of at least 50%, in order to reduce the amount
of Ni ion release when the alloy is exposed to a corrosive
environment. With respect to the structure of the material,
embodiments are directed to metallic materials that have an
amorphous structure, i.e. to Ni-based metallic glasses. With
respect to the chemical composition of the material, in one
embodiment, the metal moiety of the Ni-based metallic glass
comprises at least one of Cr, Mo, Mn, Nb, Ta, Fe, Co, and Cu. In
another embodiment, the metal moiety of the Ni-based metallic glass
comprises at least Cr. In another embodiment, the metal moiety of
the Ni-based metallic glass comprises at least Mo. In another
embodiment, the metalloid moiety of the Ni-based metallic glass
comprises at least one of P, B, and Si. In another embodiment, the
metalloid moiety of the Ni-based metallic glass comprises P and B.
In another embodiment, the metalloid moiety of the Ni-based
metallic glass comprises P and Si. In another embodiment, the
metalloid moiety of the Ni-based metallic glass comprises Si and B.
In another embodiment, the Ni-based metallic glass is free of
Ti.
[0200] In another embodiment, the Ni-based metallic glass and/or
passivated Ni-based metallic glass has a composition according to
the following formula (subscripts denote atomic percent):
Ni.sub.100-a-bX.sub.aZ.sub.b
[0201] where:
[0202] X is Cr, Mo, Mn, Nb, Ta, Fe, Co, Cu or combinations
thereof;
[0203] Z is P, B, Si, or combinations thereof;
[0204] a is between 5 and 25; and
[0205] b is between 15 and 25.
[0206] In another embodiment, X is Cr and at least one of Nb and
Ta, and Z is P and B. In another embodiment, X is Cr and Nb, and Z
is P and Si. In another embodiment, X is Mo and at least one of Nb
and Mn, and Z is P and B. In another embodiment, X is Mo and at
least one of Nb and Mn, and Z is P and Si. Example Ni-based
metallic glass alloy systems include, but are not limited to,
Ni--Cr--Nb--P--B, Ni--Co--Cr--Nb--P--B, Ni--Fe--Cr--Nb--P--B,
Ni--Cu--Cr--Nb--P--B, Ni--Cr--Nb--P--Si, Ni--Cr--Ta--P--B,
Ni--Cr--Mn--P--B, Ni--Mo--Nb--Mn--P--B, Ni--Mo--Nb--Mn--P--Si,
Ni--Mn--Nb--P--B, Ni--Mn--Nb--P--Si, Ni--Cr--Mn--Nb--P--B,
Ni--Cr--Mn--Mo--P--B, Ni--Mn--Ta--P--B, Ni--Cr--Si--B--P,
Ni--Cr--Mo--Si--B--P, and Ni--Fe--Si--B--P.
[0207] In another embodiment, the Ni-based metallic glass and/or
passivated Ni-based metallic glass has a chemical composition
represented by the following formula (subscripts denote atomic
percent):
Ni.sub.(100-a-b-c-d)Cr.sub.aNb.sub.bP.sub.cB.sub.d
where,
[0208] a is greater than 3 and less than 15;
[0209] b is greater than 1.5 and less than 4.5;
[0210] c is greater than 14.5 and less than 18.5; and
[0211] is greater than 1 and less than 5,
as described in U.S. Pat. No. 9,085,814 entitled "Bulk Nickel-Based
Chromium and Phosphorus Bearing Metallic Glasses," which is
incorporated herein by reference in its entirety.
[0212] In another embodiment, the Ni-based metallic glass and/or
passivated Ni-based metallic glass has a chemical composition
represented by the following formula (subscripts denote atomic
percent):
Ni.sub.(69-w-x-y-z)Cr.sub.8.5+wNb.sub.3+xP.sub.16.5+yB.sub.3+z
[0213] where w, x, y, and z can be positive or negative, and
where,
0.0494w.sup.2+1.78x.sup.2+4y.sup.2+z.sup.2<1,
as described in U.S. Pat. No. 9,085,814 entitled "Bulk Nickel-Based
Chromium and Phosphorus Bearing Metallic Glasses," which is
incorporated herein by reference in its entirety.
[0214] In yet another embodiment, the Ni-based metallic glass
and/or passivated Ni-based metallic glass has a composition
according to the following formula (subscripts denote atomic
percent):
Ni.sub.(100-a-b-c-d)Cr.sub.aNb.sub.bP.sub.cB.sub.d
[0215] where:
[0216] a ranges from 3 to 13;
[0217] b is determined by x-y*a, where x ranges from 3.8 to 4.2 and
y ranges from 0.11 to 0.14;
[0218] c ranges from 16.25 to 17;
[0219] d ranges from 2.75 to 3.5,
as described in U.S. Pat. Pub. No. 2014/0116579, entitled "Bulk
Nickel-Based Chromium and Phosphorus Metallic Glasses with High
Toughness," filed on Oct. 30, 2013, which is incorporated herein by
reference in its entirety.
[0220] In yet another embodiment, the Ni-based metallic glass
and/or passivated Ni-based metallic glass has a chemical
composition represented by the passivated Ni-based metallic glass
has a composition according to the following formula (subscripts
denote atomic percent):
Ni.sub.(100-a-b-c-d)Cr.sub.aNb.sub.bP.sub.cB.sub.d
[0221] where:
[0222] a ranges from 7 to 11;
[0223] b ranges from 1 to 3.25;
[0224] c ranges from 13 to 16; and
[0225] d ranges from 3 to 6.5,
as described in U.S. Pat. Pub. No. 2015/0240,336, entitled "Bulk
Nickel-Chromium-Phosphorus Glasses Bearing Niobium and Boron
Exhibiting High Strength and/or High Thermal Stability of the
Supercooled Liquid," filed on Nov. 13, 2014, which is incorporated
herein by reference in its entirety.
[0226] In yet another embodiment, the Ni-based metallic glass
and/or passivated Ni-based metallic glass has a chemical
composition according to the following formula (subscripts denote
atomic percent):
Ni.sub.(100-a-b-c-d)Cr.sub.aNb.sub.bP.sub.cB.sub.d
[0227] where:
[0228] a ranges from 7 to 11;
[0229] b ranges from 4.5 to 5.5;
[0230] c ranges from 13 to 16; and
[0231] d ranges from 4.5 to 5.5,
as described in U.S. Pat. Pub. No. 2015/0240,336, entitled "Bulk
Nickel-Chromium-Phosphorus Glasses Bearing Niobium and Boron
Exhibiting High Strength and/or High Thermal Stability of the
Supercooled Liquid," filed on Nov. 13, 2014, which is incorporated
herein by reference in its entirety.
[0232] In yet another embodiment, the Ni-based metallic glass
and/or passivated Ni-based metallic glass has a chemical
composition according to the following formula (subscripts denote
atomic percent):
Ni.sub.(100-a-b-c-d-e)X.sub.aCr.sub.bNb.sub.cP.sub.dB.sub.e
[0233] where:
[0234] a ranges from 0.5 to 30;
[0235] b ranges from 2 to 15;
[0236] c ranges from 1 to 5;
[0237] d ranges from 14 to 19;
[0238] e ranges from 1 to 5; and
[0239] wherein X can be at least one of Co, Fe, and Cu,
as described in U.S. Pat. Pub. No. 2015/0176111, entitled "Bulk
Nickel-Iron-Based, Nickel-Cobalt-Based and Nickel-Copper-Based
Glasses Bearing Chromium, Niobium, Phosphorus and Boron," filed on
Dec. 23, 2014, which is incorporated herein by reference in its
entirety.
[0240] In yet another embodiment, the Ni-based metallic glass
and/or passivated Ni-based metallic glass has a chemical
composition according to the following formula (subscripts denote
atomic percent):
Ni.sub.(100-a-b-c-d)Cr.sub.aTa.sub.bP.sub.cB.sub.d
[0241] where:
[0242] a is between 3 and 11;
[0243] b is between 1.75 and 4;
[0244] c is between 14 and 17.5; and
[0245] d is between 2.5 and 5,
as described in U.S. Pat. Pub. No. 2014/0130945, entitled "Bulk
Nickel-Phosphorus-Boron Glasses Bearing Chromium and Tantalum,"
filed on Nov. 15, 2013, which is incorporated herein by reference
in its entirety.
[0246] In yet another embodiment, the Ni-based metallic glass
and/or passivated Ni-based metallic glass has a chemical
composition according to the following formula (subscripts denote
atomic percent):
Ni.sub.(100-a-b-c-d-e)Co.sub.aCr.sub.bTa.sub.cP.sub.dB.sub.e
[0247] where:
[0248] a ranges from 0.5 to 40;
[0249] b ranges from 3 to 11;
[0250] c ranges from 1.5 to 4;
[0251] d ranges from 14 to 17.5;
[0252] e ranges from 2 to 5; and
[0253] wherein X can be at least one of Co, Fe, and Cu,
as described in U.S. patent application Ser. No. 14/501,779,
entitled "Bulk Nickel-Cobalt-Based Glasses Bearing Chromium,
Tantalum, Phosphorus and Boron," filed on Sep. 30, 2014, which is
incorporated herein by reference in its entirety.
[0254] In yet another embodiment, the Ni-based metallic glass
and/or passivated Ni-based metallic glass has a chemical
composition according to the following formula (subscripts denote
atomic percent):
Ni.sub.(100-a-b-c-d)Cr.sub.aNb.sub.bP.sub.cSi.sub.d
[0255] where:
[0256] a is between 2 and 18;
[0257] b is between 1 and 6;
[0258] c is between 16 and 20; and
[0259] d is up to 4,
as described in U.S. Pat. Pub. No. 2015/0159242, entitled "Bulk
Nickel-Based Glasses Bearing Chromium, Niobium, Phosphorus, and
Silicon," filed Dec. 9, 2014, which is incorporated by reference in
its entirety.
[0260] In yet another embodiment, the Ni-based metallic glass
and/or passivated Ni-based metallic glass has a chemical
composition according to the following formula (subscripts denote
atomic percent):
Ni.sub.(100-a-b-c)Mn.sub.aX.sub.bP.sub.cSi.sub.d
[0261] where:
[0262] a is between 0.25 and 12;
[0263] b is up to 15;
[0264] c is between 14 and 22;
[0265] d is between 0.25 and 5; and
[0266] wherein X can be at least one of Cr and Mo,
as described in U.S. Provisional Patent Application No. 61/913,684,
entitled "Bulk Nickel-Phosphorus-Silicon Glasses Bearing
Manganese," filed Nov. 11, 2014, which is incorporated by reference
in its entirety.
[0267] In yet another embodiment, the Ni-based metallic glass
and/or passivated Ni-based metallic glass has a composition
according to the following formula (subscripts denote atomic
percent):
Ni.sub.(100-a-b-c)Mn.sub.aX.sub.bP.sub.cB.sub.d
[0268] where:
[0269] a is between 0.5 and 10;
[0270] b is up to 15;
[0271] c is between 14 and 24;
[0272] d is between 1 and 8; and
[0273] wherein X can be at least one of Cr and Mo,
as described in U.S. Pat. Pub. No. 2014/0238551, entitled "Bulk
Nickel-Phosphorus-Boron Glasses Bearing Manganese," filed Feb. 26,
2014, which is incorporated by reference in its entirety.
[0274] In yet another embodiment, the Ni-based metallic glass
and/or passivated Ni-based metallic glass has a chemical
composition according to the following formula (subscripts denote
atomic percent):
N.sub.(100-a-b-c-d)Mo.sub.aNb.sub.bP.sub.cB.sub.d
[0275] where:
[0276] a is between 2 and 12;
[0277] b is up to 8;
[0278] c is between 14 and 19; and
[0279] d is between 1 and 4,
as described in U.S. Pat. Pub. No. 2014/0096873, entitled "Bulk
Nickel-Phosphorus-Boron Glasses Bearing Molybdenum," filed Feb. 26,
2014, which is incorporated by reference in its entirety.
[0280] In yet another embodiment, the Ni-based metallic glass
and/or passivated Ni-based metallic glass has a chemical
composition according to the following formula (subscripts denote
atomic percent):
Ni.sub.(100-a-b-c-d-e)Mo.sub.aNb.sub.bMn.sub.cP.sub.dB.sub.e
[0281] where:
[0282] a is between 1 and 5;
[0283] b is between 3 and 5;
[0284] c is up to 2;
[0285] d is between 16 and 17; and
[0286] e is between 2.75 and 3.75,
as described in U.S. Pat. Pub. No. 2014/0096873, entitled "Bulk
Nickel-Phosphorus-Boron Glasses Bearing Molybdenum," filed Feb. 26,
2014, which is incorporated by reference in its entirety.
[0287] In yet another embodiment, the Ni-based metallic glass
and/or passivated Ni-based metallic glass has a chemical
composition according to the following formula (subscripts denote
atomic percent):
Ni.sub.(100-a-b-c-d-e)Cr.sub.aMo.sub.bSi.sub.cB.sub.dP.sub.e
[0288] where:
[0289] a is between 3.5 and 6
[0290] b is up to 2,
[0291] c is between 4.5 and 7,
[0292] d is between 10.5 and 13, and
[0293] e is between 4 and 6,
as described in U.S. Pat. Pub. No. 2014/0076467, entitled "Bulk
Nickel-Silicon-Boron Glasses Bearing Chromium," filed Sep. 17,
2013, which is incorporated by reference in its entirety.
[0294] With respect to the chemistry of the passive layer of the
surface-treated sample, in one embodiment, where the Ni-based
metallic glass comprises Cr and P, the passive layer of the treated
sample comprises oxygen, P, and Cr. In another embodiment, where
the Ni-based metallic glass comprises Cr and P, the passive layer
of the treated sample comprises oxides and phosphides of Cr. In
another embodiment, where the Ni-based metallic glass comprises Cr,
P and B, the passive layer of the treated sample comprises oxygen,
P and/or B, and Cr. In another embodiment, where the Ni-based
metallic glass comprises Cr and P and B, the passive layer of the
treated sample comprises oxides and phosphides and/or borides of
Cr. In another embodiment, where the Ni-based metallic glass
comprises Mo and P, the passive layer of the treated sample
comprises oxygen, P, and Mo. In another embodiment, where the
Ni-based metallic glass comprises Mo and P, the passive layer of
the treated sample comprises oxides and phosphides of Mo. In
another embodiment, where the Ni-based metallic glass comprises Mo,
P and B, the passive layer of the treated sample comprises oxygen,
P and/or B, and Mo. In another embodiment, where the Ni-based
metallic glass comprises Mo and P and B, the passive layer of the
treated sample comprises oxides and phosphides and/or borides of
Mo. In another embodiment, where the Ni-based metallic glass
comprises Cr and Si, the passive layer of the treated sample
comprises oxygen, Si, and Cr. In another embodiment, where the
Ni-based metallic glass comprises Cr and Si, the passive layer of
the treated sample comprises oxides and silicides of Cr. In another
embodiment, where the Ni-based metallic glass comprises Cr, Si and
B, the passive layer of the treated sample comprises oxygen, Si
and/or B, and Cr. In another embodiment, where the Ni-based
metallic glass comprises Cr, Si and B, the passive layer of the
treated sample comprises oxides and silicides and/or borides of Cr.
In another embodiment, where the Ni-based metallic glass comprises
Mo and Si, the passive layer of the treated sample comprises
oxygen, Si, and Mo. In another embodiment, where the Ni-based
metallic glass comprises Mo and Si, the passive layer of the
treated sample comprises oxides and silicides of Mo. In another
embodiment, where the Ni-based metallic glass comprises Mo, Si and
B, the passive layer of the treated sample comprises oxygen, Si
and/or B, and Mo. In another embodiment, where the Ni-based
metallic glass comprises Mo, Si and B, the passive layer of the
treated sample comprises oxides and silicides and/or borides of Mo.
In another embodiment, the passive layer of the treated sample is
poor in Ni.
[0295] With respect to the atomic structure of the surface oxide
layer, in one embodiment, the surface oxide layer has an amorphous
structure.
[0296] With respect to the chemical treatment solution, the
disclosure is directed to a chemical treatment solution that may be
an acid solution, a chromate solution, a molybdate solution, or
combinations thereof.
[0297] In one embodiment, the chemical treatment solution comprises
an acid solution. In another embodiment, the chemical treatment
solution comprises nitric acid. In another embodiment, the chemical
treatment solution comprises nitric acid, where the nitric acid
concentration is between 5 and 60 vol. %. In another embodiment,
the chemical treatment solution comprises nitric acid, where the
nitric acid concentration is between 20 and 45 vol. %. In another
embodiment, the chemical treatment solution comprises nitric acid,
where the nitric acid concentration is between 15 and 30 vol. %. In
another embodiment, the chemical treatment solution comprises
nitric acid, where the nitric acid concentration is between 20 and
25 vol. %.
[0298] In another embodiment, the chemical treatment solution
comprises a chromate solution. In another embodiment, the chemical
treatment solution comprises sodium dichromate. In another
embodiment, the chemical treatment solution comprises sodium
dichromate, where the sodium dichromate concentration is between 5
and 200 g/L. In another embodiment, the chemical treatment solution
comprises sodium dichromate, where the sodium dichromate
concentration is between 10 and 100 g/L.
[0299] In another embodiment, the chemical treatment solution
comprises a molybdate solution. In another embodiment, the chemical
treatment solution comprises disodium molybdate. In another
embodiment, the chemical treatment solution comprises disodium
molybdate, where the disodium molybdate concentration is between 5
and 200 g/L. In another embodiment, the chemical treatment solution
comprises disodium molybdate, where the disodium molybdate
concentration is between 10 and 100 g/L.
[0300] With respect to the corrosive environment, many embodiments
of the disclosure is directed to a corrosive environment that is a
saline solution. In one embodiment, the saline solution has a pH of
at least 2. In yet another embodiment, the saline solution has a pH
of at least 4. In another embodiment, the saline solution has a pH
of at least 6. In one embodiment, the saline solution has a
concentration of NaCl of at least 0.1 g/L. In another embodiment,
the saline solution has a concentration of NaCl of at least 0.25
g/L. In yet another embodiment, the saline solution has a
concentration of NaCl of at least 1 g/L. In yet another embodiment,
the saline solution has a concentration of NaCl of at least 2 g/L.
In another embodiment, the saline solution has a concentration of
NaCl of at least 5 g/L.
[0301] In various embodiments, the disclosure is directed to a
surface treatment method for a Ni-based metallic glass comprising
immersing at least a portion of a sample of a Ni-based metallic
glass in a chemical treatment solution to produce a surface treated
portion and removing the surface treated portion from the chemical
treatment solution to terminate the chemical surface treatment. In
many such embodiments the chemical treatment solution comprises at
least one of an acid solution, a chromate solution, and a molybdate
solution. After treatment with such embodiments, the Ni ion release
rate from the surface treated portion of the sample when immersed
in a saline solution for one day is less than 80% of the Ni ion
release rate from an as-cast Ni-based metallic glass sample having
the same composition similarly immersed in the saline solution for
one day.
[0302] In another embodiment, the first chemical treatment solution
comprises a nitric acid solution.
[0303] In another embodiment, the nitric acid concentration in the
nitric acid solution is between 5 and 60 volume %.
[0304] In another embodiment, the nitric acid concentration in the
nitric acid solution is between 20 and 45 volume %.
[0305] In another embodiment, the surface treatment method
comprises at least two immersion steps. In such embodiments, the
method includes (1) immersing at least a portion of the Ni-based
metallic glass in a first chemical treatment solution comprising an
acid to produce a surface treated portion, and (2) removing the
surface treated portion from the first chemical treatment
solution.
[0306] The method may further include immersing the surface treated
portion in a second chemical treatment solution. In many
embodiments the second chemical solution comprises at least one of
a chromate solution and a molybdenum solution. The surface treated
portion is also removed from the second chemical treatment
solution.
[0307] After treatment, the Ni ion release rate from the surface
treated portion when immersed in a saline solution for one day is
less than 80% of the Ni ion release rate from an as-cast Ni-based
metallic glass sample having the same composition immersed in the
saline solution for one day.
[0308] In another embodiment, the second chemical treatment
solution comprises a sodium dichromate solution.
[0309] In another embodiment, the sodium dichromate concentration
in the sodium dichromate solution is between 5 and 200 g/L.
[0310] In another embodiment, the sodium dichromate concentration
in the sodium dichromate solution is between 10 and 100 g/L.
[0311] In another embodiment, the second chemical treatment
solution comprises a disodium molybdate solution.
[0312] In another embodiment, the disodium molybdate concentration
in the disodium molybdate solution is between 5 and 200 g/L.
[0313] In another embodiment, the disodium molybdate concentration
in the disodium molybdate solution is between 10 and 100 g/L.
[0314] In one embodiment, the saline solution is a biological
solution. In another embodiment, the saline solution is saliva. In
another embodiment, the saline solution is perspiration. In another
embodiment, the saline solution is blood. In another embodiment,
the saline solution is simulated body fluid. In another embodiment,
the saline solution is artificial saliva. In another embodiment,
the saline solution is artificial perspiration. In another
embodiment, the saline solution is artificial blood. In another
embodiment, the saline solution is sea water. In another
embodiment, the saline solution is simulated sea water.
DEFINITIONS
[0315] For the purpose of this disclosure, Ni ion release refers to
the mass of extracted Ni ions from a sample exposed to a corrosive
environment per surface area of the sample, measured in units of
.mu.g/cm.sup.2.
[0316] For the purpose of this disclosure, the Ni ion release rate
means the mass of extracted Ni ions from a sample exposed to a
corrosive environment per surface area of the sample per day,
measured in units of .mu.g/cm.sup.2/day.
[0317] For the purpose of this disclosure, in some embodiments, a
steady-state Ni ion release rate means the Ni ion released rate
varies by less than 40% as a function of time in the extraction
solution. In other embodiments, a steady-state Ni ion release rate
means the Ni ion released rate varies by less than 20% as a
function of time in the extraction solution, while in yet other
embodiments by less than 10% as a function of time in the
extraction solution. In certain embodiments, a steady-state Ni ion
release rate means the Ni ion released rate varies by less than 0.1
.mu.g/cm.sup.2/day as a function of time in the extraction
solution, while in other embodiments by less than 0.06
.mu.g/cm.sup.2/day as a function of time in the extraction
solution, while in yet other embodiments by less than 0.03
.mu.g/cm.sup.2/day as a function of time in the extraction
solution.
[0318] For the purpose of this disclosure, "as-cast metallic glass"
refers to a metallic glass in its as-formed or as-quenched state
that has not undergone any chemical surface treatment.
[0319] For the purpose of this disclosure, "Ni-based metallic
glass" refers to a metallic glass that comprises Ni at an atomic
fraction of at least 50%.
[0320] For the purpose of this disclosure, the "organic layer"
refers to an outermost layer (i.e. the most exterior layer) of the
material comprising organic compounds that include elements such as
O, C, H and N. The organic layer extends from the outermost surface
of the material to a depth into the material where the
concentration of Cr peaks. In embodiments of the disclosure, the
"organic layer" is not regarded to be an integral part of the
"passivated Ni-based metallic glass."
[0321] For the purpose of this disclosure, "passivated Ni-based
metallic glass" refers to a Ni-based metallic glass that comprises
an inner "bulk material" portion and an outer "passive layer"
portion.
[0322] For the purpose of this disclosure, the "passive layer"
refers to the outer portion of a Ni-based metallic glass (with the
organic layer disregarded) that may comprise oxygen in which the
atomic concentration of oxygen changes by more than 1% per
nanometer of depth into the material (or equivalently, by more than
0.1% per angstrom of depth into the material). In some embodiments,
the passive layer may be amorphous (i.e. at least 90% amorphous by
volume, or in other embodiments at least 95% amorphous by volume,
or in other embodiments at least 98% amorphous by volume). In other
embodiments, the passive layer may be crystalline (i.e. more 10%
crystalline by volume, or in other embodiments more than 30%
crystalline by volume, or in other embodiments more than 50%
crystalline by volume).
[0323] For the purpose of this disclosure, the "bulk material"
refers to the inner portion (the inner bulk material portion) of a
Ni-based metallic glass that may comprise oxygen in which the
atomic concentration of oxygen changes by less than 1% per
nanometer of depth into the material. The inner bulk material
portion is substantially amorphous (i.e. at least 90% amorphous by
volume, or in other embodiments at least 95% amorphous by volume,
or in other embodiments at least 98% amorphous by volume).
[0324] For the purpose of this disclosure, the metal moiety of the
Ni-based metallic glass refers to the composition of transition
metals included in the alloy other than Ni.
[0325] For the purpose of this disclosure, the metalloid moiety of
the Ni-based metallic glass refers to the composition of
metalloids, semimetals, or non-metals included in the alloy.
[0326] For the purpose of this disclosure, a Ni-based metallic
glass free of Ti refers to a Ni-based metallic glass that contains
Ti in an atomic fraction that is equal to or less than the atomic
fraction consistent with an incidental impurity. In some
embodiments, a Ni-based metallic glass free of Ti refers to a
Ni-based metallic glass that contains Ti in an atomic fraction that
is equal to or less than 1%. In other embodiments, a Ni-based
metallic glass free of Ti refers to a Ni-based metallic glass that
contains Ti in an atomic fraction that is equal to or less than
0.5%. In yet other embodiments, a Ni-based metallic glass free of
Ti refers to a Ni-based metallic glass that contains Ti in an
atomic fraction that is equal to or less than 0.1%.
[0327] For the purpose of this disclosure, a saline solution refers
to an aqueous solution that comprises at least sodium chloride. In
some embodiments, the saline solution is a biological solution,
including without limitation saliva, perspiration, and blood
plasma. In other embodiments, the saline solution is a
physiological solution, including without limitation artificial
saliva, artificial perspiration, and artificial blood plasma. In
other embodiments, the saline solution is sea water. In yet other
embodiments, the saline solution is simulated sea water.
[0328] For the purpose of this disclosure, the passive layer of the
surface treated sample being poor in Ni refers to a passive layer
comprising Ni at a concentration of less than 60 percent of the
nominal concentration of Ni in the inner bulk material portion, and
in some embodiments less than 40 percent, in other embodiments less
than 20 percent, in other embodiments less than 10 percent, while
in other embodiments less than 5 percent.
[0329] Surface Treatment Process
[0330] Many embodiments are directed to a method of chemically
surface treating a Ni-based metallic glass comprising at least one
immersion step that comprises: [0331] immersing the Ni-based
metallic glass sample in a chemical treatment solution under
specified chemical treatment conditions to produce a surface
treated metallic glass; and [0332] removing the surface-treated
metallic glass sample from the chemical treatment solution; where
the amount of Ni released by the surface-treated metallic glass
when exposed to a saline containing environment is lower compared
to a metallic glass that has not undergone any chemical surface
treatment
[0333] Optionally, the surface-treated metallic glass may be rinsed
and dried.
[0334] In some embodiments, the chemical treatment solution
comprises an acid solution, a chromate solution, a molybdate
solution, or a combination thereof.
[0335] In some embodiments, the method of chemically surface
treating a Ni-based metallic glass involves at least two immersion
steps. In one embodiment, at least one step comprises immersion in
an acid solution and at least one other step comprises immersion in
a chromate solution. In another embodiment, at least one step
comprises immersion in an acid solution and at least one other step
comprises immersion in a molybdate solution.
[0336] For the purpose of this disclosure, immersing the Ni-based
metallic glass sample in a chemical treatment solution may comprise
exposing one or more portions of the metallic glass sample to the
chemical treatment solution under the chemical treatment conditions
in order to chemically surface-treat the metallic glass sample.
[0337] For the purposes of this disclosure, chemical treatment
conditions may include any combination of acid solution a chromate
solution, a molybdate solution, or a combination thereof, and also
any combination of temperature and immersion time suitable to
produce a surface treated metallic glass.
[0338] For the purposes of this disclosure, the Ni-ion release rate
of the surface treated metallic glass when exposed to a saline
containing environment is lower compared to the Ni ion release rate
from an as-cast Ni-based metallic glass sample having the same
composition exposed to the same saline environment for the same
period.
[0339] In many embodiments the decrease in the Ni ion release rate
for the chemically surface treated Ni-based metallic glass sample
when exposed to a saline-containing environment for one day is less
than 80% of the Ni ion release rate from an as-cast Ni-based
metallic glass sample having the same composition immersed in the
same saline solution for the same period.
[0340] Any chemical treatment conditions, including immersion time
and chemical treatment solution temperature, suitable to produce a
surface-treated Ni-based metallic glass sample may be used. In some
embodiments, the immersion time is at least 1 min. In one
embodiment, the immersion time is at least 10 minutes. In another
embodiment, the immersion time is at least 30 minutes. In another
embodiment, the immersion time is at least 60 minutes. In yet
another embodiment, the immersion time is at least 180 minutes. In
yet another embodiment, the immersion time is at least 360 minutes.
In some embodiments, the temperature of the chemical treatment
solution is at least as high as room temperature. In one
embodiment, the temperature of the chemical treatment solution is
at least 40.degree. C. In another embodiment, the temperature of
the chemical treatment solution is at least 50.degree. C. In yet
another embodiment, the temperature of the chemical treatment
solution is at least 60.degree. C. In some embodiments, the
temperature of the chemical treatment solution is below 100.degree.
C. In one embodiment, the temperature of the chemical treatment
solution is below 80.degree. C. In another embodiment, the
temperature of the chemical treatment solution is below 70.degree.
C. In yet another embodiment, the temperature of the chemical
treatment solution is below 60.degree. C. The time required for
passivation may be temperature dependent with passivation occurring
more quickly at higher temperatures. Accordingly, in other
embodiments the acid solution temperature may be less than
80.degree. C., and the immersion time may be at least 1 minute.
[0341] For the purposes of this disclosure, any suitable method of
rinsing and drying the sample as may be known in the art suitable
to remove any unwanted residues from the sample prior to working
may be utilized.
[0342] Surface Treatment of Example Alloys
[0343] To demonstrate the effects of the current surface
preparation method, the family of Ni--Cr--Nb--P--B--(Si)
glass-forming alloys, disclosed in recent applications (U.S. Patent
Application No. 61/526,153, entitled "Bulk Nickel-Based Chromium
and Phosphorous Bearing Metallic Glasses," filed on Aug. 22, 2011,
and U.S. Patent Application No. 61/720,015, entitled "Bulk
Nickel-Based Chromium and Phosphorous Bearing Metallic Glasses with
High Toughness," filed on Oct. 30, 2012), is investigated.
[0344] The effect of surface treatment on the Ni-ion release rates
of Ni.sub.71.4Cr.sub.5.52Nb.sub.3.38P.sub.16.67B.sub.3.03 metallic
glass over an immersion period of up to 15 days in a saline
solution is investigated. Two different acid solutions were tested
as chemical treatment solutions: a 20 volume % nitric acid, and a
10 weight % citric acid. For both solutions the metallic glass
samples were immersed in the chemical treatment solutions at room
temperature for 60 minutes. Ni was extracted from the two surface
treated samples as well as from an as-cast sample by immersing the
samples in a Phosphate Buffered Saline (PBS) solution, which is a
simulated body fluid solution whose osmolarity and ion
concentrations of the solutions match those of the human body.
[0345] The effect of surface treatments in nitric acid and citric
acid solutions on the Ni ion release rate of
Ni.sub.71.4Cr.sub.5.52Nb.sub.3.38P.sub.16.67B.sub.3.03 metallic
glass in Phosphate Buffered Saline solution are shown in FIGS. 1
and 2 respectively. Ni-ion release rate data are provided in Tables
1 and 2. The daily Ni-ion release rates are provided in Table 1,
while the weekly Ni-ion release rates are provided in Table 2. The
first column in Table 1 lists the total period (in days) that a
sample is immersed in solution. The second column lists the period
of extraction, that is, the immersion period in a new solution. The
third, fourth, and fifth columns list the average daily Ni ion
release rate (averaged over the period of extraction) recorded for
the as-cast sample, the sample that has undergone surface treatment
in nitric acid solution, and the sample that has undergone surface
treatment in citric acid solution, respectively. Table 2 provides
the weekly Ni-ion release rates observed during the first and
second week of immersion.
TABLE-US-00001 TABLE 1 Effect of surface treatments in a 20 volume
% nitric acid solution and a 10 weight % citric acid solution on
the average daily Ni-ion release rate of
Ni.sub.71.4Cr.sub.5.52Nb.sub.3.38P.sub.16.67B.sub.3.03 metallic
glass in a Phosphate Buffered Saline solution. Total Ni-ion Release
Rate (.mu.g/cm.sup.2/day) Immersion Extraction Surface-treated
Surface-treated Period (days) Period (days) As-cast in Nitric Acid
in Citric Acid 1 1 1.000 0.260 0.920 7 6 0.350 0.217 0.283 15 8
0.325 0.238 0.250
TABLE-US-00002 TABLE 2 Effect of surface treatments in a 20 volume
% nitric acid solution and a 10 weight % citric acid solution on
the weekly Ni-ion release rate of
Ni.sub.71.4Cr.sub.5.52Nb.sub.3.38P.sub.16.67B.sub.3.03 metallic
glass in a Phosphate Buffered Saline solution. Ni-ion Release Rate
(.mu.g/cm.sup.2/week) Surface-treated in Surface-treated in As-cast
Nitric Acid Citric Acid week 1 3.10 1.56 2.62 week 2 2.60 1.90
2.00
[0346] The effect of surface treatment on the Ni-ion release rates
of
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass over an immersion period of up to 15 days in a
saline solution was investigated. A chemical treatment solution
comprising a 20 volume % nitric acid solution was used. The
metallic glass sample was immersed in the solution at room
temperature for 60 minutes. Ni was extracted from the surface
treated sample as well as from an as-cast sample by immersing the
samples in a Fusayama/Mayer artificial saliva (FAS) solution that
resembles the mineral composition of natural saliva and is the most
common media used for testing dental metal alloys.
[0347] The effect of surface treatment in nitric acid solution on
the Ni ion release rate of
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass in a Fusayama/Mayer artificial saliva (FAS) solution
is illustrated in FIG. 3 and Tables 3 and 4. The daily Ni-ion
release rates are provided in Table 3, while the weekly Ni-ion
release rates are provided in Table 4. The first column in Table 3
lists the total period that a sample is immersed in the FAS
solution. The second column lists the period of extraction, that
is, the immersion period in a new solution. The third and fourth
columns list the average daily Ni ion release rate (averaged over
the period of extraction) recorded for the untreated as-cast
sample, and the sample that has undergone surface treatment in
nitric acid solution, respectively. Table 4 provides the weekly
Ni-ion release rates observed during the first and second week of
immersion.
TABLE-US-00003 TABLE 3 Effect of surface treatments in 20 volume %
nitric acid solution on the average daily Ni-ion release rate of
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass in a Fusayama/Mayer artificial saliva solution.
Total Ni-ion Release Rate (.mu.g/cm.sup.2/day) Immersion Extraction
Surface-treated in Period (days) Period (days) As-cast Nitric Acid
1 1 0.650 0.082 7 6 0.057 0.028 15 8 0.029 0.014
TABLE-US-00004 TABLE 4 Effect of surface treatments in 20 volume %
nitric acid solution on the weekly Nickel-ion release rate of
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass in a Fusayama/Mayer artificial saliva solution.
Ni-ion Release Rate (.mu.g/cm.sup.2/week) Surface-treated in
As-cast Nitric Acid week 1 0.99 0.25 week 2 0.23 0.11
[0348] As seen in Tables 1 and 3 and FIGS. 1-3, in both PBS and FAS
solutions, regardless of the alloy compositions and surface
treatments, the average daily Ni release rates are the highest on
the first day, and decrease rapidly as a function of time to
achieve near steady-state levels after 7 days of immersion.
[0349] However, the surface treatment in nitric acid solution
decreased the Ni release rates by .about.70-90% for both
Ni.sub.71.4Cr.sub.5.52Nb.sub.3.38P.sub.16.67B.sub.3.03 metallic
glass in PBS extraction solution, and
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
in the FAS extraction solution. The Ni-ion release rates in
Ni.sub.71.4Cr.sub.5.52Nb.sub.3.38P.sub.16.67B.sub.3.03 that
underwent surface-treatment in nitric acid are 0.260
.mu.g/cm.sup.2/day on day 1 in simulated body fluid (PBS solution).
As a comparison, the Ni release rate in the as-cast untreated
material is 1.000 .mu.g/cm.sup.2/day, which corresponds to a
.about.74% higher Ni release rate (Table 1). In comparison, the
Ni-ion release rates in
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28S.sub.0.5
that underwent surface-treatment in nitric acid is 0.082
.mu.g/cm.sup.2/day on day 1 in artificial saliva. In contrast, the
Ni release rate in the untreated material is 0.650
.mu.g/cm.sup.2/day, which corresponds to a .about.87% higher Ni
release rate (Table 3).
[0350] After 7 days of immersion, the Ni release rates in the
untreated as-cast samples of both
Ni.sub.71.4Cr.sub.5.52Nb.sub.3.38P.sub.16.67B.sub.3.03 and
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
decreased significantly by 65% and 91%, respectively, and reached a
near steady-state rate. However, the decay in Ni release rates in
the Ni.sub.71.4Cr.sub.5.52Nb.sub.3.38P.sub.16.67B.sub.3.03 and
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28S.sub.0.5
samples that have undergone surface-treatment in nitric acid is
less significant--16% and 65% after 7 days, respectively. The
latter indicates that the nitric acid surface treatment is very
effective at creating a stable passive oxide layer and in limiting
the bulk of Ni extraction within day 1, thereby enabling the
Ni-release process to reach a near steady state in roughly one day.
In comparison, the Ni release process in the untreated as-cast Ni
alloys takes roughly 7 days to reach a near steady-state.
[0351] Similarly, for the first week of immersion, the surface
treatment in nitric acid solution decreased the weekly Ni release
rates of both
Ni.sub.71.4Cr.sub.5.52Nb.sub.3.38P.sub.16.67B.sub.3.03 and
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
by 50% and 77%, respectively, as compared to the untreated as-cast
samples (Tables 2 and 4). On the second week of immersion, the
weekly Ni release rates of both surface-treated
Ni.sub.71.4Cr.sub.5.52Nb.sub.3.38P.sub.16.67B.sub.3.03 and
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
has decreased by 27% and 52%, respectively, as compared to the
untreated as-cast samples for a similar immersion period.
[0352] The Ni release rates in
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
are significantly lower than in
Ni.sub.71.4Cr.sub.5.52Nb.sub.3.38P.sub.16.67B.sub.3.03 in both the
samples that have undergone surface-treatment in nitric acid and
the untreated as-cast samples throughout the entire immersion
period. The difference may be due to the difference in extraction
solution--PBS vs FAS media. Another factor may be the difference in
the Cr content of the alloys.
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
has a higher Cr content than
Ni.sub.71.4Cr.sub.5.52Nb.sub.3.38P.sub.16.67B.sub.3.03.
[0353] On the other hand, the surface treatment in citric acid
(FIG. 2) on the Nickel-ion release rate of alloy
Ni.sub.71.4Cr.sub.5.52Nb.sub.3.38P.sub.16.67B.sub.3.03 had a less
pronounced effect on the Ni leaching. Compared to the Ni release
rate of the as-cast untreated sample, the Ni release rate of the
sample that has undergone surface-treatment in citric acid
decreased by .about.8% from 1.000 to 0.920 .mu.g/cm.sup.2/day on
day 1. This demonstrates that the citric acid surface treatment,
which is commonly used in surface treatments of stainless steel, is
not as suitable as nitric acid for providing passivation of
Ni-based metallic glasses and reducing Ni release in a saline
solution.
[0354] In agreement with several studies and as readily accepted by
the Food Drug Administration, a threshold Nickel release value of
35 .mu.g/day (Sunderman F W, Jr. "Potential toxicity from nickel
contamination of intravenous fluids" Annals of Clinical &
Laboratory Science, 1983 13:1-4) is needed to trigger a cytotoxic
response. According to the Ni release rates provided in Tables 1
and 3, Ni-based metallic glass samples with composition of
Ni.sub.71.4Cr.sub.5.52Nb.sub.3.38P.sub.16.67B.sub.3.03 and
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5,
having a surface area up to 134 cm.sup.2 and 426 cm.sup.2
respectively, that have undergone a surface treatment according to
the methods disclosed herein, would not give rise to Ni
toxicity.
[0355] Therefore, metallic glass samples that have undergone a
surface treatment according to the methods disclosed herein and
have a surface area such that the total Ni ion release rate would
not exceed 35 .mu.g/day would not give rise to Ni toxicity. In some
embodiments, such samples can be used as biomedical components,
implants, or devices, including without limitation dental,
orthodontic, endodontic, orthopedic, masculofascial, cardiovascular
components, implants, or devices.
[0356] The effect of surface treatment using chemical treatment
solutions comprising a chromate solution on the Ni-ion release rate
of
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass over an immersion period of 7 days in a saline
solution is investigated. Four different chemical treatment
processes using solutions that comprise a chromate solution were
performed as follows: (1) a 50 g/L sodium dichromate
(Na.sub.2Cr.sub.2O.sub.7) solution, (2) a solution comprising 20
volume % nitric acid combined with 44 g/L sodium dichromate, (3) a
solution comprising 40 volume % nitric acid combined with 22 g/L
sodium dichromate, (4) and a two-step chemical solution treatment,
where the first solution comprises 20 volume % nitric acid combined
with 25 g/L sodium dichromate, and the second solution comprises 50
g/L sodium dichromate. In all four chemical treatment processes,
the metallic glass samples were immersed in the chemical treatment
solutions at 60.degree. C. for 30 minutes. Ni was extracted from
the four surface treated samples as well as from an untreated
as-polished sample by immersing the samples in an artificial
perspiration solution prepared according to standard BS
EN1811:2011, which is a simulated perspiration solution whose
osmolarity and ion concentrations of the solutions match those of
the human skin.
[0357] The effect of surface treatments in chemical treatment
solutions comprising a chromate solution on the Ni ion release rate
of
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass extracted in an artificial perspiration solution are
shown in FIG. 4. Table 5 provides the weekly Ni-ion release rates
observed during the first week of immersion.
TABLE-US-00005 TABLE 5 Effect of surface treatments in chemical
treatment solutions comprising a chromate solution on the weekly
Ni-ion release rate of
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass extracted in an artificial perspiration solution.
Ni-ion Release Rate Passivation Solution (.mu.g/cm.sup.2/week)
Untreated (as-polished) 1.70 50 g/L Na.sub.2Cr.sub.2O.sub.7 0.62 20
vol. % HNO.sub.3, 44 g/L Na.sub.2Cr.sub.2O.sub.7 0.066 40 vol. %
HNO.sub.3, 22 g/L Na.sub.2Cr.sub.2O.sub.7 0.083 Step 1: 20 vol. %
HNO.sub.3, 22 g/L Na.sub.2Cr.sub.2O.sub.7 0.032 Step 2: 50 g/L
Na.sub.2Cr.sub.2O.sub.7
[0358] As seen in Table 5 and FIG. 4, the most effective surface
treatment process in reducing Ni leaching is the a two-step
chemical solution treatment with the first solution comprising 20
volume % nitric acid combined with 25 g/L sodium dichromate and the
second solution comprises 50 g/L sodium dichromate, as the weekly
Ni leach from the treated sample was just 0.032
.mu.g/cm.sup.2/week, i.e. about 98% decrease compared to the Ni
leach form an untreated sample of 1.7 .mu.g/cm.sup.2/week. The
second most effective surface treatment process in reducing Ni
leaching is treatment in a solution comprising 20 volume % nitric
acid combined with 44 g/L sodium dichromate, as the weekly Ni leach
from the treated sample was 0.066 .mu.g/cm.sup.2/week, i.e. about
96% decrease compared to the Ni leach form an untreated sample of
1.7 .mu.g/cm.sup.2/week. The third most effective surface treatment
process in reducing Ni leaching is treatment in a solution
comprising 40 volume % nitric acid combined with 22 g/L sodium
dichromate, as the weekly Ni leach from the treated sample was
0.083 .mu.g/cm.sup.2/week, i.e. about 95% decrease compared to the
Ni leach form an untreated sample of 1.7 .mu.g/cm.sup.2/week. The
fourth most effective surface treatment process in reducing Ni
leaching is treatment in a solution comprising 50 g/L sodium
dichromate, as the weekly Ni leach from the treated sample was 0.62
.mu.g/cm.sup.2/week, i.e. about 64% decrease compared to the Ni
leach form an untreated sample of 1.7 .mu.g/cm.sup.2/week.
[0359] To demonstrate the effects of the current surface
preparation method, the family of Ni--Mo--Nb--Mn--P--Si
glass-forming alloys, disclosed in recent applications (U.S. patent
application Ser. No. 14/824,733), is investigated.
[0360] The effect of surface treatment using chemical treatment
solutions comprising a chromate solution on the Ni-ion release rate
of Ni.sub.73.0Mo.sub.2.5Nb.sub.3.5Mn.sub.1.5P.sub.18.0Si.sub.1.5
metallic glass over an immersion period of 7 days in a saline
solution is investigated. A chemical treatment process using
solutions that comprise a chromate solution was performed as
follows: a two-step chemical solution treatment, where the first
solution comprises 20 volume % nitric acid combined with 25 g/L
sodium dichromate, and the second solution comprises 50 g/L sodium
dichromate. In this chemical treatment process, the metallic glass
sample was immersed in the chemical treatment solutions at
60.degree. C. for 30 minutes. Ni was extracted from the treated
sample as well as from an untreated as-polished sample by immersing
the samples in an artificial perspiration solution prepared
according to standard BS EN1811:2011, which is a simulated
perspiration solution whose osmolarity and ion concentrations of
the solutions match those of the human skin.
[0361] In some embodiments, metallic glass samples that have
undergone a surface treatment according to the methods disclosed
herein can be used as products or articles that are in contact with
the skin over extended periods of time, including without
limitation ornamental products (e.g. necklaces or rings), watches,
or electronic phones.
[0362] Analysis of Surface Chemistry of Example Alloy
[0363] The chemical composition and depth profile of the passive
layer of as polished (i.e. untreated) and surface treated,
according to embodiments of the disclosure,
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass was investigated by XPS/ESCA and SIMS.
[0364] An "organic layer" comprising organic compounds that include
elements such as O, C, H and N was detected in samples analyzed,
having a thickness of less than about 5 angstrom.
[0365] In the XPS analysis it is difficult to detect B in the
presence of P, because the sole peak of B (B1s) overlaps with one
of the P peaks (P2s), and also because XPS is more sensitive to P
than B. Hence, in the context of this disclosure, the XPS detection
of P may also imply detection of B, and will be denoted as P/B
implying detection of P and/or B.
[0366] Also, Si was not detected in the XPS analysis, since the
atomic concentration of Si in the investigated alloy is very low
(0.5%). Hence the concentration distribution of Si in the bulk and
surface of the material is not known from this analysis.
[0367] Calcium, which is not a constituent or a large impurity of
the alloys disclosed herein, was detected on the surface of treated
samples as opposed to the as-polished sample, where calcium
concentration is negligibly small (<1 at. %). The calcium
concentration increases with the concentration of the nitric acid
solution. The presence of calcium and the increase in its
concentration as the concentration of the nitric acid solution is
increased suggest that Ca ions are deposited on the surface from
the distilled water used in the dilution of the nitric acid
solution.
[0368] Table 6 contains XPS sputter depth profile data obtained for
an untreated as-polished
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass rod. Data for the composition of the organic layer
are not included. The data shows that the surface layer of the
untreated as-polished sample comprises 0, P/B, Cr, Nb and Ni (a
negligible concentration of Ca was also detected). The thickness of
the passive layer (with the organic layer disregarded) is
approximately 30 angstrom. The average atomic concentration of O
within the passive layer thickness is about 7.2%, that of P/B about
13.1%, that of Cr about 5.5%, that of Nb about 3.0%, and that of Ni
about 55.6%. The concentration of P/B is higher in the passive
layer than in the inner bulk material portion; the concentration of
Cr is approximately the same in the passive layer and inner bulk
material portion; while the concentrations of Nb and Ni are lower
in the passive layer than in the inner bulk material portion. This
suggests that Ni and possibly Nb leach out of the surface into the
solution as P/B diffuses from the bulk material to the surface to
form the passive layer by combining with O and possibly Cr.
TABLE-US-00006 TABLE 6 Atomic concentrations of elements detected
by XPS analysis as a function of depth on the surfacef as-polished
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass sample. Element Concentration (in atomic %) Depth
(.ANG.) O P/B Cr Nb Ni Ca 0 15.87 14.24 5.88 2.67 53.66 0.83 10
6.76 14.25 5 2.62 67.58 0.32 20 3.47 13.22 5.43 2.99 71.53 0.22 30
2.76 10.54 5.74 3.59 74.8 0.14 45 2.17 8.58 6.46 4.25 75.14 0.19 60
1.84 8.67 6.35 5.19 77.53 0.01 75 1.33 7.81 6.72 5.72 76.17 0 90
1.1 8.72 6.67 5.95 76.17 0 105 1.59 8.33 6.64 6.25 75.69 0 120 0.51
8.68 6.87 6.6 75.53 0 140 0.65 7.9 7.07 6.9 76.28 0 160 0.45 8.53
7.01 7.19 76.29 0 180 0.25 8.67 6.99 7.14 74.76 0
[0369] Table 7 contains XPS sputter depth profile data obtained for
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass rods surface treated in a 20 vol. % nitric acid
solution for 60 minutes. Data for the composition of the organic
layer are not included. The data shows that the passive layers of
the surface treated samples comprise O, P/B, Cr, Nb, and Ni (along
with a small concentration of Ca). The thickness of the passive
layer (with the organic layer disregarded) is approximately 45
angstrom, i.e. about 50% thicker compared to the as-polished
sample. The average atomic concentration of O within the passive
layer thickness is about 14%, that of P/B about 17.3%, that of Cr
about 7.0%, that of Nb about 3.8%, and that of Ni about 55.6%. The
concentration of P/B is higher in the passive layer than in the
inner bulk material portion; the concentration of Cr is slightly
higher in the passive layer than in the inner bulk material
portion; while the concentrations of Nb and Ni are lower in the
passive layer than in the inner bulk material portion. This
suggests that Ni and possibly Nb leaches out of the surface into
the solution as P/B and Cr diffuse from the bulk material to the
surface to form the passive layer by combining with O. Compared to
the as-polished sample, the average concentration of O in the
passive layer of the treated sample is about 97% higher, the
average concentration of P/B in the passive layer of the treated
sample is about 33% higher, the average concentration of Cr in the
passive layer of the treated sample is about 27% higher, the
average concentration of Nb in the passive layer of the treated
sample is about 28% higher, while the average concentration of Ni
in the passive layer of the treated sample is about 17% lower.
[0370] Hence, in one embodiment, the average concentration of O
within the passive layer thickness of a sample of a Ni-based
metallic glass comprising Cr and P/B that has been surface treated
in a nitric acid solution of concentration of at least 15 vol. %
for at least 30 minutes is at least 50% higher when compared to an
untreated sample. In another embodiment, the average concentration
of P/B within the passive layer thickness of a sample of a Ni-based
metallic glass comprising Cr and P/B that has been surface treated
in a nitric acid solution of concentration of at least 15 vol. %
for at least 30 minutes is at least 20% higher when compared to an
untreated sample. In another embodiment, the average concentration
of Cr within the passive layer thickness of a sample of a Ni-based
metallic glass comprising Cr and P/B that has been surface treated
in a nitric acid solution of concentration of at least 15 vol. %
for at least 30 minutes is at least 15% higher when compared to an
untreated sample. In another embodiment, the average concentration
of Ni within the passive layer thickness of a sample of a Ni-based
metallic glass comprising Cr and P/B that has been surface treated
in a nitric acid solution of concentration of at least 15 vol. %
for at least 30 minutes is at least 10% lower when compared to an
untreated sample. In other embodiments, the passive layer of a
sample of a Ni-based metallic glass comprising Cr and P/B that has
been surface treated in a nitric acid solution of concentration of
at least 15 vol. % for at least 30 minutes is at least 25% thicker
when compared to an untreated sample.
TABLE-US-00007 TABLE 7 Atomic concentrations of elements detected
by XPS analysis as a function of depth on the surface of polished
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass sample after surface treatment in a 20 vol. % Nitric
solution. Element Concentration (in atomic %) Depth (.ANG.) O P/B
Cr Nb Ni Ca 0 39.25 18.11 8.78 3.39 25.29 2.61 10 19.01 20 7.17
3.64 48.14 1.41 20 7.26 19.48 5.94 3.34 61.86 0.68 30 3.02 16.35
6.41 4.02 69.66 0.32 45 1.26 12.71 6.63 4.57 73.15 0.26 60 0.66
9.98 7.37 5.69 75.25 0.03 75 0 7.77 7.14 6.05 77.49 0 90 0.38 9.06
6.77 6.63 74.87 0 105 1.08 10.1 7.1 6.77 73.73 0 120 0.55 9.83 6.82
7.43 75.02 0 140 0.43 8.7 6.79 7.55 76.02 0 160 0.39 8.64 7.42 7.74
74.49 0 180 0 9.4 6.88 8 74.66 0
[0371] Table 8 contains XPS sputter depth profile data obtained for
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass rods surface treated in a 30 vol. % nitric acid
solution for 60 minutes. Data for the composition of the organic
layer are not included. The data shows that the passive layers of
the surface treated samples comprise O, P/B, Cr, Nb, and Ni (along
with a small concentration of Ca). The thickness of the passive
layer (with the organic layer disregarded) is approximately 60
angstrom, i.e. about 100% thicker compared to the as-polished
sample. The average atomic concentration of O within the passive
layer thickness is about 18%, that of P/B about 16.8%, that of Cr
about 7.5%, that of Nb about 4.1%, and that of Ni about 50.8%. The
concentration of P/B is higher in the passive layer than in the
inner bulk material portion; the concentration of Cr is slightly
higher in the passive layer than in the inner bulk material
portion; while the concentrations of Nb and Ni are lower in the
passive layer than in the inner bulk material portion. This
suggests that Ni and possibly Nb leach out of the surface into the
solution as P/B and Cr diffuse from the bulk material to the
surface to form the passive layer by combining with O. Compared to
the as-polished sample, the average concentration of 0 in the
passive layer of the treated sample is about 150% higher, the
average concentration of P/B in the passive layer of the treated
sample is about 28% higher, the average concentration of Cr in the
passive layer of the treated sample is about 37% higher, the
average concentration of Nb in the passive layer of the treated
sample is about 39% higher, while the average concentration of Ni
in the passive layer of the treated sample is about 24% lower.
[0372] Hence, in one embodiment, the average concentration of O
within the passive layer thickness of a sample of a Ni-based
metallic glass comprising Cr and P/B that has been surface treated
in a nitric acid solution of concentration of at least 25 vol. %
for at least 30 minutes is at least 75% higher when compared to an
untreated sample. In another embodiment, the average concentration
of P/B within the passive layer thickness of a sample of a Ni-based
metallic glass comprising Cr and P/B that has been surface treated
in a nitric acid solution of concentration of at least 25 vol. %
for at least 30 minutes is at least 20% higher when compared to an
untreated sample. In another embodiment, the average concentration
of Cr within the passive layer thickness of a sample of a Ni-based
metallic glass comprising Cr and P/B that has been surface treated
in a nitric acid solution of concentration of at least 25 vol. %
for at least 30 minutes is at least 20% higher when compared to an
untreated sample. In another embodiment, the average concentration
of Ni within the passive layer thickness of a sample of a Ni-based
metallic glass comprising Cr and P/B that has been surface treated
in a nitric acid solution of concentration of at least 25 vol. %
for at least 30 minutes is at least 15% lower when compared to an
untreated sample. In other embodiments, the passive layer of a
sample of a Ni-based metallic glass comprising Cr and P/B that has
been surface treated in a nitric acid solution of concentration of
at least 25 vol. % for 60 minutes is at least 50% thicker when
compared to an untreated sample.
TABLE-US-00008 TABLE 8 Atomic concentrations of elements detected
by XPS analysis as a function of depth on the surface of polished
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass sample after surface treatment in a 30 vol. % Nitric
solution. Element Concentration (in atomic %) Depth (.ANG.) O P/B
Cr Nb Ni Ca 0 50.8 17.16 8.23 3.62 15.72 3.74 10 32.71 18.55 9.15
3.92 32.36 2.96 20 15.82 19.83 7.56 3.95 49.64 1.56 30 6.01 19.12
6.69 3.89 61.63 0.67 45 2.4 14.34 6.72 4.22 69.93 0.14 60 0.41 11.5
6.94 5.18 75.71 0 75 0.76 9.64 7.07 5.71 74.37 0 90 0.24 9.29 7.51
6.25 75.5 0 105 0.28 8.95 7.36 6.63 74.9 0 120 0.49 8.17 7.13 6.78
75.13 0 140 0.16 8.95 6.84 7.32 75.28 0 160 0.45 9.09 7.28 7.81
74.57 0 180 0.28 7.72 7.83 7.95 76.03 0
[0373] Table 9 contains XPS sputter depth profile data obtained for
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass rods surface treated in a 40 vol. % nitric acid
solution for 60 minutes. Data for the composition of the organic
layer are not included. The data shows that the passive layers of
the surface treated samples comprise O, P/B, Cr, Nb, and Ni (along
with a small concentration of Ca). The thickness of the passive
layer (with the organic layer disregarded) is approximately 90
angstrom, i.e. about 200% thicker compared to the as-polished
sample. The average atomic concentration of O within the passive
layer thickness is about 29.6%, that of P/B about 16.3%, that of Cr
about 8.1%, that of Nb about 4.8%, and that of Ni about 38.1%. The
concentration of P/B is higher in the passive layer than in the
inner bulk material portion; the concentration of Cr is slightly
higher in the passive layer than in the inner bulk material
portion; while the concentrations of Nb and Ni are lower in the
passive layer than in the inner bulk material portion. This
suggests that Ni and possibly Nb leach out of the surface into the
solution as P/B and Cr diffuse from the inner bulk material portion
to the surface to form the passive layer by combining with O.
Compared to the as-polished sample, the average concentration of O
in the passive layer of the treated sample is about 310% higher,
the average concentration of P/B in the passive layer of the
treated sample is about 24% higher, the average concentration of Cr
in the passive layer of the treated sample is about 47% higher, the
average concentration of Nb in the passive layer of the treated
sample is about 61% higher, while the average concentration of Ni
in the passive layer of the treated sample is about 43% lower.
[0374] Hence, in one embodiment, the average concentration of O
within the passive layer thickness of a sample of a Ni-based
metallic glass comprising Cr and P/B that has been surface treated
in a nitric acid solution of concentration of at least 35 vol. %
for at least 30 minutes is at least 100% higher when compared to an
untreated sample. In another embodiment, the average concentration
of P/B within the passive layer thickness of a sample of a Ni-based
metallic glass comprising Cr and P/B that has been surface treated
in a nitric acid solution of concentration of at least 35 vol. %
for at least 30 minutes is at least 20% higher when compared to an
untreated sample. In another embodiment, the average concentration
of Cr within the passive layer thickness of a sample of a Ni-based
metallic glass comprising Cr and P/B that has been surface treated
in a nitric acid solution of concentration of at least 35 vol. %
for at least 30 minutes is at least 30% higher when compared to an
untreated sample. In another embodiment, the average concentration
of Ni within the passive layer thickness of a sample of a Ni-based
metallic glass comprising Cr and P/B that has been surface treated
in a nitric acid solution of concentration of at least 35 vol. %
for at least 30 minutes is at least 25% lower when compared to an
untreated sample. In other embodiments, the passive layer of a
sample of a Ni-based metallic glass comprising Cr and P/B that has
been surface treated in nitric acid solution of concentration of at
least 35 vol. % for 60 minutes is at least 100% thicker when
compared to an untreated sample.
TABLE-US-00009 TABLE 9 Atomic concentrations of elements detected
by XPS analysis as a function of depth on the surface of polished
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass sample after surface treatment in a 40 vol. % Nitric
solution. Element Concentration (in atomic %) Depth (.ANG.) O P/B
Cr Nb Ni Ca 0 64.43 16.26 7.17 3.92 1.98 3.55 10 59.75 17.16 8.37
4.62 5.4 3.8 20 50.99 16.45 9.34 5.17 13.31 3.71 30 37.21 18.52
9.71 5.04 26.75 2.7 45 14.93 19.79 8.17 4.41 50.29 1.17 60 6.09
17.56 7.49 4.31 62.86 0.61 75 2.75 13.39 7.33 5.03 69.69 0.2 90
0.88 10.87 7.34 5.78 74.89 0 105 0.32 10.04 7.75 6.3 74.53 0 120
0.54 9.08 7.58 6.77 74.47 0 140 0.31 9.28 7.18 7.1 73.26 0.19 160
0.67 8.71 7.05 7.47 75.31 0 180 0.57 8.95 7.04 7.55 74.86 0
[0375] FIGS. 5-9 provide plots of depth profile up to 200 angstrom
for the detected elements by XPS on the surfaces of the as-polished
and surface treated samples, including O (FIG. 5), P/B (FIG. 6), Cr
(FIG. 7), Nb (FIG. 8), and Ni (FIG. 9), respectively. Data for the
composition of the organic layer are not included in the plots.
[0376] Table 10 contains SIMS sputter depth profile data up to 60
angstrom in depth obtained for an untreated as-polished
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass rod. Data for the composition of the organic layer
are included, but the concentrations of the elements that
contribute to the formation of the organic compounds, such as C, H,
and N, are not included. The data shows that the organic layer has
a thickness of about 4 angstrom (or less than 5 angstrom), and in
addition to C, H, and N, the organic layer also comprises primarily
O and Si, and is depleted in P, Cr, Nb, B, and Ni. The average
atomic concentration of O within the organic layer (within the
first 4 angstrom) is about 39.9%, that of Si about 10.7%, that of P
about 17.4%, that of Cr about 2.9%, that of Nb about 0.5%, that of
B about 0.7%, and that of Ni about 30.2%.
[0377] Data for the composition of the surface passive layer, which
is the layer immediately adjacent to the organic layer (i.e.
extending beyond about 5 angstrom), is presented in Table 11. The
composition data suggest that the thickness of the passive layer
(excluding the organic layer) is approximately 14 angstrom, and is
enriched in O, P, and Cr. The average atomic concentration of O
within the passive layer is about 3.9%, that of P about 29.2%, that
of Cr about 4.6%, that of Nb about 0.23%, that of B about 0.97%,
that of Si about 0.77%, and that of Ni about 60.5%.
[0378] The concentration of P is significantly higher in the
passive layer than in the inner bulk material portion; the
concentrations of Cr, Ni, and Si are approximately the same in the
passive layer and inner bulk material portion; while the
concentrations of Nb and B are significantly lower in the passive
layer than in the inner bulk material portion. This suggests that
Nb and B leach out of the surface into the solution as P diffuses
from the bulk material to the surface to form the passive layer by
combining with O and possibly Cr.
TABLE-US-00010 TABLE 10 Atomic concentrations of elements detected
by SIMS analysis as a function of depth on the surface of an
as-polished (untreated)
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass sample. Element Concentration (in atomic %) Depth
(.ANG.) O P Cr Nb B Si Ni 0 32.48 9.59 0.40 1.49 1.36 28.42 19.30 1
53.32 13.67 1.47 0.28 0.50 8.54 26.85 3 45.66 20.20 3.83 0.14 0.43
3.81 32.41 4 28.15 26.30 5.82 0.13 0.36 2.02 42.24 5 14.84 31.19
6.09 0.14 0.35 1.29 49.94 7 8.19 32.97 5.34 0.15 0.39 0.90 53.53 8
5.01 34.01 4.52 0.16 0.45 0.69 55.82 9 3.39 33.17 4.20 0.17 0.53
0.58 57.94 11 2.43 32.22 3.85 0.18 0.69 0.56 59.76 12 1.96 30.96
3.88 0.20 0.85 0.62 61.06 13 1.61 29.28 4.02 0.22 1.06 0.68 62.28
14 1.42 26.67 4.24 0.26 1.26 0.74 64.45 16 1.30 24.97 4.61 0.33
1.47 0.79 65.76 17 1.16 23.31 4.98 0.36 1.66 0.82 67.14 18 1.05
21.92 5.21 0.41 1.86 0.77 68.20 20 0.98 20.88 5.47 0.46 2.03 0.76
68.89 21 0.88 19.63 5.81 0.51 2.12 0.76 70.03 22 0.82 19.27 6.06
0.58 2.24 0.72 70.29 23 0.79 18.80 6.34 0.62 2.36 0.71 70.19 25
0.71 18.32 6.58 0.68 2.45 0.67 70.52 26 0.64 17.87 6.80 0.74 2.53
0.68 70.51 27 0.63 17.05 6.95 0.79 2.57 0.65 71.07 29 0.58 17.57
7.15 0.86 2.66 0.67 71.01 30 0.50 17.63 7.35 0.91 2.69 0.64 70.27
31 0.51 17.01 7.36 1.00 2.70 0.60 70.49 33 0.47 16.82 7.48 0.99
2.75 0.58 71.08 34 0.44 16.72 7.76 1.07 2.84 0.60 70.52 35 0.40
16.99 7.89 1.16 2.81 0.58 70.42 36 0.37 16.94 7.80 1.22 2.84 0.55
70.19 38 0.37 16.88 7.88 1.24 2.91 0.61 70.17 39 0.33 16.77 7.94
1.28 2.87 0.59 70.19 40 0.32 16.45 8.23 1.34 2.89 0.55 70.26 42
0.28 16.43 8.18 1.43 2.97 0.53 70.19 43 0.27 16.72 8.25 1.49 3.00
0.58 69.83 44 0.27 16.58 8.29 1.57 3.06 0.60 69.59 45 0.24 16.62
8.29 1.58 3.02 0.54 69.77 47 0.23 16.68 8.35 1.63 3.09 0.61 69.52
48 0.22 16.75 8.37 1.66 3.08 0.54 69.44 49 0.20 16.60 8.47 1.66
3.10 0.55 69.30 51 0.18 16.40 8.45 1.72 3.06 0.55 69.49 52 0.19
16.36 8.47 1.79 3.10 0.57 69.76 53 0.19 15.17 8.52 1.77 2.88 0.56
69.21 54 0.16 15.47 7.75 1.79 3.05 0.48 72.82 56 0.16 16.35 8.50
1.96 3.16 0.55 69.20 57 0.16 16.40 8.66 1.95 3.17 0.51 69.35 58
0.14 16.51 8.82 2.02 3.20 0.53 68.77 60 0.14 16.62 8.58 2.03 3.25
0.53 68.99
[0379] Table 11 contains SIMS sputter depth profile data obtained
for
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass rods surface treated in a 20 vol. % nitric acid
solution for 60 minutes. Data for the composition of the organic
layer are included, but the concentrations of the elements that
contribute to the formation of the organic compounds, such as C, H,
and N, are not included. The data shows that the organic layer has
a thickness of about 4 angstrom (or less than 5 angstrom), and in
addition to C, H, and N, the organic layer is rich in O, Si, and P,
and is depleted in Cr, Nb, B, and Ni. The average atomic
concentration of O within the organic layer thickness (within the
first 4 angstrom) is about 49.1%, that of Si about 7.1%, that of P
about 24.8%, that of Cr about 3.3%, that of Nb about 0.15%, that of
B about 0.5%, and that of Ni about 16.3%.
[0380] Data for the composition of the passive layer, which is the
layer immediately adjacent to the organic layer (i.e. extending
beyond about 5 angstrom), is presented in Table 10. The composition
data suggest that the thickness of the passive layer (excluding the
organic layer) is approximately 14 angstrom, and is enriched in O
and P and poor in Nb and B. The average atomic concentration of O
within the passive layer thickness is about 4.6%, that of P about
35.3%, that of Cr about 5.8%, that of Nb about 0.3%, that of B
about 0.94%, that of Si about 0.54%, and that of Ni about
52.8%.
[0381] The concentration of P is significantly higher in the
passive layer than in the inner bulk material portion; the
concentration of Si is approximately the same in the passive layer
as in the inner bulk material portion; the concentrations of Cr and
Ni are slightly lower in the passive layer than in the inner bulk
material portion; while the concentrations of B and Nb are
significantly lower in the passive layer than in the inner bulk
material portion. This suggests that Nb and B and possibly Ni and
Cr leach out of the surface into the solution as P diffuses from
the bulk material to the surface to form the passive layer by
combining with O and possibly Cr.
[0382] Compared to the passive layer of the as-polished sample, the
average concentration of O in the passive layer of the treated
sample is about 19% higher, the average concentration of P in the
passive layer of the treated sample is about 21% higher, the
average concentration of Cr in the passive layer of the treated
sample is about 25% higher, the average concentration of Nb in the
passive layer of the treated sample is about 30% higher, the
average concentration of B in the passive layer of the treated
sample is about 3% lower, the average concentration of Si in the
passive layer of the treated sample is about 30% lower, while the
average concentration of Ni in the passive layer of the treated
sample is about 12% lower.
[0383] Hence, in one embodiment, the average concentration of O
within the passive layer thickness of a sample of a Ni-based
metallic glass comprising Cr and P that has been surface treated in
a nitric acid solution of concentration of at least 15 vol. % for
at least 30 minutes is at least 5% higher when compared to an
untreated sample. In another embodiment, the average concentration
of P within the passive layer thickness of a sample of a Ni-based
metallic glass comprising Cr and P that has been surface treated in
a nitric acid solution of concentration of at least 15 vol. % for
at least 30 minutes is at least 10% higher when compared to an
untreated sample. In another embodiment, the average concentration
of Cr within the passive layer thickness of a sample of a Ni-based
metallic glass comprising Cr and P that has been surface treated in
a nitric acid solution of concentration of at least 15 vol. % for
at least 30 minutes is at least 15% higher when compared to an
untreated sample. In another embodiment, the average concentration
of Ni within the passive layer thickness of a sample of a Ni-based
metallic glass comprising Cr and P that has been surface treated in
a nitric acid solution of concentration of at least 15 vol. % for
at least 30 minutes is at least 5% lower when compared to an
untreated sample.
TABLE-US-00011 TABLE 11 Atomic concentrations of elements detected
by SIMS analysis as a function of depth on the surface of polished
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass sample after surface treatment in a 20 vol. % nitric
acid solution. Element Concentration (in atomic %) Depth (.ANG.) O
P Cr Nb B Si Ni 0 39.09 17.84 0.70 0.31 0.81 22.18 8.10 1 68.22
21.91 1.79 0.08 0.37 3.57 9.26 3 54.81 27.01 4.27 0.10 0.41 1.65
17.60 4 34.11 32.34 6.56 0.12 0.41 1.08 30.23 5 19.12 35.98 7.28
0.16 0.43 0.85 39.58 7 10.59 37.57 6.81 0.19 0.47 0.59 45.51 8 6.41
38.13 6.06 0.22 0.48 0.48 48.92 9 4.02 38.02 5.55 0.25 0.56 0.42
51.45 11 2.82 37.85 5.24 0.26 0.66 0.35 52.94 12 2.11 37.64 5.04
0.27 0.77 0.39 53.80 13 1.64 36.04 5.15 0.31 0.93 0.43 54.83 14
1.31 34.41 5.26 0.34 1.11 0.51 56.30 16 1.10 32.59 5.43 0.39 1.36
0.55 58.14 17 0.94 30.77 5.65 0.43 1.68 0.66 59.02 18 0.76 28.86
5.91 0.48 1.90 0.67 60.60 20 0.72 26.50 6.17 0.52 2.16 0.72 62.27
21 0.65 25.19 6.47 0.56 2.42 0.72 63.66 22 0.56 23.76 6.90 0.65
2.58 0.73 64.21 23 0.53 22.63 6.99 0.70 2.73 0.69 65.18 25 0.44
21.40 7.16 0.78 2.87 0.74 66.13 26 0.40 20.85 7.47 0.82 2.99 0.73
66.65 27 0.40 20.23 7.65 0.93 3.09 0.67 66.97 29 0.35 19.61 7.91
0.96 3.21 0.63 67.08 30 0.32 19.26 7.97 1.03 3.23 0.60 67.36 31
0.32 18.46 8.00 1.08 3.28 0.62 67.85 33 0.25 18.22 8.29 1.10 3.27
0.58 68.37 34 0.25 18.25 8.39 1.28 3.42 0.53 68.08 35 0.24 18.30
8.36 1.26 3.43 0.54 67.88 36 0.21 17.79 8.49 1.34 3.46 0.57 67.75
38 0.21 17.61 8.58 1.33 3.43 0.56 68.30 39 0.19 17.57 8.70 1.45
3.43 0.56 68.28 40 0.18 17.69 8.74 1.52 3.54 0.55 67.73 42 0.16
17.29 8.84 1.59 3.58 0.55 67.91 43 0.15 16.93 8.75 1.63 3.55 0.56
68.22 44 0.14 17.02 8.95 1.62 3.46 0.51 68.39 45 0.13 17.25 9.04
1.77 3.53 0.54 67.95 47 0.12 17.20 8.85 1.74 3.56 0.51 67.97 48
0.13 16.82 8.82 1.72 3.60 0.50 68.12 49 0.13 17.06 8.94 1.79 3.55
0.57 68.17 51 0.11 17.01 8.83 1.87 3.55 0.50 68.25 52 0.12 17.29
8.81 1.98 3.70 0.53 67.80 53 0.11 17.23 8.96 1.94 3.71 0.52 67.42
54 0.12 17.04 8.92 1.98 3.62 0.51 67.66 56 0.09 16.76 8.98 2.01
3.56 0.54 68.01 57 0.08 17.15 9.05 2.09 3.62 0.50 67.80 58 0.09
17.11 8.99 2.15 3.65 0.51 67.53 60 0.09 16.83 8.93 2.16 3.70 0.52
67.49
[0384] FIGS. 10-16 provide plots of depth profile up to 200
angstrom for the detected elements by SIMS on the surfaces of the
as-polished and surface treated samples, including O (FIG. 10), P
(FIG. 11), Cr (FIG. 12), Nb (FIG. 13), B (FIG. 14), Si (FIG. 15),
and Ni (FIG. 16), respectively. The insets provide plots of depth
profile up to 60 angstrom for the detected elements, and the
regions for the "organic layer," "passive layer," and "bulk
material" are designated by arrows.
[0385] The depth profiles indicate the samples have a general
profile comprising a passive layer that has thickness in the range
of 10 to 100 angstrom, with the thickness increasing with
increasing the concentration of the nitric acid solution. The inner
bulk material portion of the metallic glass alloy is located
underneath the passive layer.
[0386] Table 12 contains SIMS sputter depth profile data obtained
for
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass rods surface treated in 50 g/L sodium dichromate at
60.degree. C. for 30 minutes. Data for the composition of the
organic outermost layer are included, but the concentrations of the
elements that contribute to the formation of the organic compounds,
such as C, H, and N, are not included. The data shows that the
organic layer has a thickness of about 8 angstrom (or less than 9
angstrom), and in addition to C, H, and N, the organic layer is
also rich in O and Si and is depleted in Cr, Nb, B, and Ni. The
average atomic concentration of O within the organic layer
thickness (within the first 8 angstrom) is about 64.1%, that of Si
about 4.5%, that of P about 14.1%, that of Cr about 3.5%, that of
Nb about 0.21%, that of B about 0.45%, and that of Ni about
15.1%.
[0387] Data for the composition of the passive layer, which is the
layer immediately adjacent to the organic layer (i.e. extending
beyond about 8 angstrom), is presented in Table 11. The composition
data suggest that the thickness of the passive layer (excluding the
organic layer) is approximately 63 angstrom, and is rich in O and P
and poor in Nb and B. The average atomic concentration of O within
the passive layer thickness is about 8.5%, that of P about 22.6%,
that of Cr about 4.8%, that of Nb about 0.45%, that of B about
1.6%, that of Si about 0.72%, and that of Ni about 61.4%.
[0388] Compared to the passive layer of the as-polished sample,
whose thickness is about 13 angstrom, the passive layer thickness
of the treated sample is about 385% thicker. Hence, in one
embodiment, the passive layer of a sample that has been surface
treated in a sodium dichromate solution having concentration of at
least 25 g/L at temperature of at least 45.degree. C. for at least
15 minutes is at least 50% thicker than the passive layer of an
untreated sample. In another embodiment, the passive layer of a
sample of a sample that has been surface treated in a sodium
dichromate solution having concentration of at least 25 g/L at
temperature of at least 45.degree. C. for at least 15 minutes is at
least 100% thicker than the passive layer of an untreated sample.
In another embodiment, the passive layer of a sample that has been
surface treated in a sodium dichromate solution having
concentration of at least 25 g/L at temperature of at least
45.degree. C. for at least 15 minutes is at least 200% thicker than
the passive layer of an untreated sample. In yet another
embodiment, the passive layer of a sample that has been surface
treated in a sodium dichromate solution having concentration of at
least 25 g/L at temperature of at least 45.degree. C. for at least
15 minutes is at least 300% thicker than the passive layer of an
untreated sample.
TABLE-US-00012 TABLE 12 Atomic concentrations of elements detected
by SIMS analysis as a function of depth on the surface of polished
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass sample after surface treatment in a 50 g/L sodium
dichromate solution. Element Concentration (in atomic %) Depth
(.ANG.) O P Cr Nb B Si Ni 0 64.09 7.76 1.83 0.56 0.84 12.72 8.34 2
73.65 11.35 2.98 0.14 0.35 2.40 10.87 5 66.62 15.36 4.03 0.08 0.28
1.64 16.20 7 51.86 22.05 5.18 0.06 0.25 1.31 25.01 9 34.91 26.33
5.27 0.04 0.25 1.09 35.67 11 24.57 29.19 4.45 0.05 0.30 0.90 43.04
14 18.89 29.86 3.74 0.06 0.36 0.75 47.50 16 15.54 29.77 3.32 0.07
0.49 0.73 50.36 18 14.00 28.08 3.17 0.09 0.62 0.73 52.73 20 13.04
25.86 3.18 0.10 0.79 0.73 55.37 22 12.14 24.45 3.29 0.13 0.95 0.80
57.90 25 11.12 23.37 3.46 0.15 1.06 0.77 59.78 27 10.34 22.72 3.69
0.19 1.23 0.77 60.94 29 9.56 22.34 3.81 0.22 1.33 0.74 61.94 31
8.73 21.79 4.04 0.24 1.38 0.73 63.12 34 8.05 21.58 4.26 0.27 1.50
0.71 63.72 36 7.37 21.95 4.42 0.31 1.57 0.69 64.05 38 6.76 22.00
4.54 0.35 1.72 0.72 64.13 40 6.14 21.55 4.73 0.40 1.78 0.69 64.57
42 5.54 21.40 4.85 0.42 1.84 0.70 65.41 45 5.08 21.33 5.09 0.46
1.91 0.67 65.58 47 4.69 21.36 5.19 0.52 2.01 0.67 65.82 49 4.12
21.40 5.32 0.58 2.13 0.69 65.82 51 3.86 20.74 5.46 0.61 2.16 0.71
66.31 54 3.56 20.72 5.57 0.66 2.19 0.69 66.66 56 3.22 20.62 5.75
0.71 2.27 0.70 66.86 58 2.99 20.42 5.78 0.76 2.37 0.65 66.92 60
2.71 20.08 5.93 0.80 2.40 0.68 67.41 62 2.49 19.39 6.02 0.84 2.45
0.68 67.86 65 2.30 19.53 6.14 0.91 2.50 0.67 68.21 67 2.10 19.64
6.23 0.98 2.58 0.67 67.89 69 2.00 19.61 6.29 1.00 2.63 0.64 67.87
71 1.80 19.04 6.34 1.05 2.69 0.64 68.15 74 1.72 18.84 6.48 1.08
2.66 0.66 68.57 76 1.61 18.90 6.49 1.14 2.73 0.64 68.67 78 1.49
18.93 6.57 1.19 2.79 0.64 68.44 80 1.41 18.54 6.64 1.26 2.78 0.66
68.48 82 1.35 18.43 6.69 1.28 2.80 0.62 68.79 85 1.25 18.27 6.78
1.30 2.80 0.63 69.06 87 1.16 18.26 6.87 1.38 2.90 0.65 68.78 89
1.11 18.22 6.95 1.44 2.91 0.65 68.73 91 1.08 17.77 6.87 1.44 2.88
0.64 69.10 94 0.99 17.68 7.00 1.46 2.88 0.62 69.39 96 0.92 17.87
7.06 1.57 2.93 0.64 69.22 98 0.89 18.04 7.04 1.58 2.96 0.64 68.91
100 0.84 17.60 7.09 1.58 2.97 0.64 69.02 102 0.81 17.43 7.17 1.63
2.97 0.64 69.31 105 0.77 17.46 7.23 1.67 2.97 0.64 69.37 107 0.73
17.78 7.26 1.73 3.00 0.63 69.08 109 0.72 17.53 7.31 1.75 3.08 0.64
68.89 111 0.69 17.33 7.32 1.78 3.05 0.64 69.01 114 0.62 17.28 7.27
1.79 3.03 0.63 69.41 116 0.63 17.43 7.40 1.87 3.07 0.63 69.14 118
0.60 17.47 7.47 1.90 3.13 0.63 68.93 120 0.59 17.33 7.38 1.89 3.06
0.63 68.82 123 0.55 16.91 7.41 1.89 3.07 0.61 69.50 125 0.57 17.03
7.55 1.97 3.07 0.62 69.33 127 0.54 17.11 7.61 2.01 3.09 0.64 69.06
129 0.48 17.09 7.52 2.03 3.13 0.61 69.10 131 0.49 17.14 7.58 2.04
3.13 0.63 69.00 134 0.48 16.93 7.65 2.02 3.07 0.61 69.17 136 0.48
17.04 7.73 2.09 3.10 0.63 69.08 138 0.45 17.24 7.68 2.10 3.18 0.60
68.80 140 0.43 17.34 7.68 2.14 3.16 0.65 68.67 143 0.43 16.87 7.68
2.11 3.15 0.63 68.84 145 0.42 16.75 7.77 2.19 3.12 0.62 69.17 147
0.39 17.15 7.82 2.16 3.14 0.62 68.96 149 0.41 16.99 7.76 2.24 3.18
0.59 68.75 151 0.39 16.83 7.85 2.23 3.19 0.61 68.76 154 0.39 16.71
7.83 2.22 3.14 0.63 69.02 156 0.36 16.92 7.93 2.26 3.14 0.61 68.99
158 0.36 17.02 7.97 2.32 3.19 0.62 68.56 160 0.34 16.97 7.90 2.32
3.16 0.62 68.61 163 0.34 16.72 7.80 2.34 3.13 0.61 68.96 165 0.34
16.68 8.00 2.32 3.14 0.62 69.00 167 0.33 16.86 8.06 2.37 3.17 0.59
68.67 169 0.31 17.09 7.94 2.36 3.20 0.64 68.56 171 0.31 16.76 7.98
2.39 3.19 0.60 68.54 174 0.29 16.45 8.09 2.39 3.17 0.65 68.93 176
0.30 16.48 8.07 2.46 3.16 0.61 68.90 178 0.30 16.87 8.05 2.47 3.21
0.63 68.78 180 0.28 16.92 8.04 2.47 3.24 0.61 68.44 183 0.27 16.91
8.05 2.42 3.23 0.61 68.36 185 0.28 16.65 8.08 2.41 3.18 0.63 68.72
187 0.27 16.77 8.12 2.50 3.23 0.59 68.72 189 0.27 16.69 8.19 2.51
3.26 0.58 68.43 191 0.24 16.69 8.11 2.48 3.24 0.61 68.50 194 0.22
16.64 8.08 2.44 3.16 0.63 68.82 196 0.23 16.40 8.22 2.49 3.18 0.56
68.89 198 0.22 16.92 8.22 2.53 3.28 0.62 68.54 200 0.23 16.77 8.26
2.55 3.26 0.59 68.16 203 0.23 16.75 8.13 2.52 3.22 0.59 68.59 205
0.21 16.82 8.20 2.54 3.21 0.62 68.44 207 0.21 16.54 8.30 2.62 3.20
0.61 68.40 209 0.21 16.76 8.28 2.63 3.30 0.58 68.45 212 0.21 16.62
8.24 2.58 3.29 0.58 68.29 214 0.20 16.56 8.26 2.60 3.25 0.61 68.46
216 0.22 16.50 8.32 2.62 3.23 0.63 68.49 218 0.20 16.51 8.29 2.59
3.23 0.60 68.63 220 0.18 16.79 8.31 2.63 3.29 0.60 68.34 223 0.20
16.60 8.25 2.65 3.22 0.60 68.31 225 0.18 16.48 8.28 2.59 3.24 0.61
68.55 227 0.18 16.33 8.33 2.60 3.24 0.59 68.78 229 0.18 16.51 8.44
2.66 3.30 0.60 68.37 232 0.18 16.76 8.33 2.64 3.26 0.60 68.28 234
0.19 16.27 8.23 2.63 3.24 0.60 68.62 236 0.16 16.53 8.41 2.64 3.22
0.62 68.60 238 0.17 16.56 8.38 2.65 3.25 0.58 68.48 240 0.17 16.62
8.44 2.74 3.28 0.61 68.17 243 0.17 16.73 8.34 2.70 3.27 0.60 68.16
245 0.16 16.59 8.39 2.72 3.25 0.61 68.27 247 0.16 16.58 8.37 2.70
3.26 0.59 68.40 249 0.16 16.88 8.42 2.74 3.24 0.60 68.04 252 0.17
16.72 8.36 2.70 3.33 0.56 68.14 254 0.14 16.38 8.40 2.67 3.27 0.59
68.27 256 0.15 16.29 8.43 2.68 3.25 0.61 68.61 258 0.14 16.68 8.46
2.71 3.22 0.61 68.39 260 0.14 16.78 8.45 2.71 3.25 0.61 68.11 263
0.14 16.36 8.37 2.75 3.26 0.59 68.29 265 0.13 16.53 8.39 2.72 3.23
0.61 68.52 267 0.13 16.49 8.52 2.71 3.20 0.58 68.31 269 0.14 16.69
8.48 2.71 3.24 0.57 68.34 272 0.13 16.62 8.42 2.77 3.27 0.56 68.09
274 0.13 16.51 8.38 2.75 3.31 0.59 68.42 276 0.13 16.36 8.45 2.75
3.24 0.58 68.32 278 0.12 16.61 8.59 2.78 3.27 0.60 68.27 280 0.13
16.73 8.44 2.79 3.29 0.61 67.98 283 0.12 16.48 8.44 2.74 3.34 0.58
68.19 285 0.12 16.33 8.40 2.79 3.29 0.59 68.40 287 0.12 16.43 8.54
2.74 3.25 0.58 68.43 289 0.11 16.64 8.48 2.79 3.30 0.58 68.19 292
0.11 16.47 8.51 2.80 3.29 0.58 68.22 294 0.11 16.56 8.51 2.74 3.28
0.61 68.05 296 0.12 16.28 8.51 2.78 3.29 0.60 68.51 298 0.11 16.34
8.58 2.80 3.25 0.56 68.25 300 0.11 16.83 8.48 2.83 3.26 0.57 68.22
303 0.11 16.55 8.49 2.82 3.29 0.58 67.98 305 0.11 16.49 8.45 2.76
3.31 0.58 68.32 307 0.11 16.29 8.53 2.79 3.26 0.57 68.33 309 0.10
16.62 8.61 2.82 3.32 0.58 68.25 312 0.10 16.65 8.54 2.84 3.32 0.54
67.93 314 0.09 16.52 8.53 2.89 3.32 0.58 67.92 316 0.09 16.18 8.44
2.77 3.26 0.58 68.53 318 0.09 16.50 8.51 2.85 3.26 0.57 68.47 321
0.10 16.42 8.56 2.85 3.32 0.59 68.15 323 0.09 16.47 8.53 2.81 3.30
0.58 68.11 325 0.09 16.31 8.47 2.85 3.25 0.59 68.39 327 0.09 16.21
8.61 2.80 3.25 0.58 68.41 329 0.10 16.42 8.62 2.86 3.26 0.59 68.36
332 0.09 16.55 8.52 2.85 3.32 0.58 68.15 334 0.09 16.55 8.51 2.82
3.29 0.54 68.05 336 0.08 16.31 8.52 2.81 3.26 0.56 68.40 338 0.09
16.50 8.60 2.82 3.26 0.57 68.34 341 0.09 16.70 8.64 2.87 3.30 0.59
67.84 343 0.08 16.50 8.59 2.89 3.29 0.57 68.04 345 0.08 16.41 8.58
2.84 3.34 0.55 68.02 347 0.08 16.59 8.59 2.87 3.23 0.58 68.21 349
0.07 16.41 8.59 2.86 3.30 0.56 68.21
[0389] FIGS. 17-23 provide plots of depth profiles up to 350
angstrom for the detected elements by SIMS on the surfaces of the
as-polished sample and the sample surface treated in a 50 g/L
sodium dichromate solution, including O (FIG. 17), P (FIG. 18), Cr
(FIG. 19), Nb (FIG. 20), B (FIG. 21), Si (FIG. 22), and Ni (FIG.
23), respectively. The insets provide plots of depth profiles up to
100 angstrom for the detected elements, and the regions for the
"organic layer," "passive layer," and "bulk material" are
designated by arrows.
[0390] Table 13 contains SIMS sputter depth profile data obtained
for
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass rods surface treated by a two-step chemical solution
treatment (the first solution comprises 20 volume % nitric acid
combined with 25 g/L sodium dichromate, and the second solution
comprises 50 g/L sodium dichromate) at 60.degree. C. for 30 minutes
in each step. Data for the composition of the organic outermost
layer are included, but the concentrations of the elements that
contribute to the formation of the organic compounds, such as C, H,
and N, are not included. The data shows that the organic layer has
a thickness of about 8 angstrom (or less than 9 angstrom), and in
addition to C, H, and N, the organic layer is also rich in O and Si
and is depleted in Cr, Nb, B, and Ni. The average atomic
concentration of O within the organic layer thickness (within the
first 8 angstrom) is about 54.8%, that of Si about 10.6%, that of P
about 16.2%, that of Cr about 5.6%, that of Nb about 0.21%, that of
B about 0.63%, and that of Ni about 15.1%.
[0391] Data for the composition of the passive layer, which is the
layer immediately adjacent to the organic layer (i.e. extending
beyond about 8 angstrom), is presented in Table 11. The composition
data suggest that the thickness of the passive layer (excluding the
organic layer) is approximately 12 angstrom, and is rich in O and P
and poor in Ni, Nb and B. The average atomic concentration of O
within the passive layer thickness is about 1.45%, that of P about
31.7%, that of Cr about 6.2%, that of Nb about 0.31%, that of B
about 1.2%, that of Si about 0.51%, and that of Ni about 57.7%.
[0392] The concentration of P is significantly higher in the
passive layer than in the inner bulk material portion; the
concentration of Si is approximately the same in the passive layer
as in the inner bulk material portion; the concentration of Cr is
slightly lower in the passive layer than in the inner bulk material
portion; while the concentrations of Ni, B and Nb are significantly
lower in the passive layer than in the inner bulk material portion.
This suggests that Nb and B and possibly Ni and Cr leach out of the
surface into the solution as P diffuses from the bulk material to
the surface to form the passive layer by combining with O and
possibly Cr.
[0393] Compared to the passive layer of the as-polished sample, the
average concentration of O in the passive layer of the treated
sample is about 63% lower, the average concentration of P in the
passive layer of the treated sample is about 9% higher, the average
concentration of Cr in the passive layer of the treated sample is
about 34% higher, the average concentration of Nb in the passive
layer of the treated sample is about 36% lower, the average
concentration of B in the passive layer of the treated sample is
about 23% lower, the average concentration of Si in the passive
layer of the treated sample is about 34% lower, while the average
concentration of Ni in the passive layer of the treated sample is
about 5% lower.
[0394] Hence, in one embodiment, the average concentration of P
within the passive layer thickness of a sample of a Ni-based
metallic glass comprising Cr and P that has been surface treated by
a two-step chemical solution treatment, where the first solution
comprises nitric acid combined with odium dichromate, and the
second solution comprises sodium dichromate, for at least 15
minutes is at least 5% higher when compared to an untreated sample.
In another embodiment, the average concentration of Cr within the
passive layer thickness of a sample of a Ni-based metallic glass
comprising Cr and P that has been surface treated by a two-step
chemical solution treatment, where the first solution comprises
nitric acid combined with odium dichromate, and the second solution
comprises sodium dichromate, for at least 15 minutes is at least
25% higher when compared to an untreated sample. In another
embodiment, the average concentration of Ni within the passive
layer thickness of a sample of a Ni-based metallic glass comprising
Cr and P that has been surface treated by a two-step chemical
solution treatment, where the first solution comprises nitric acid
combined with odium dichromate, and the second solution comprises
sodium dichromate, for at least 15 minutes is at least 2% lower
when compared to an untreated sample.
TABLE-US-00013 TABLE 13 Atomic concentrations of elements detected
by SIMS analysis as a function of depth on the surface of polished
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass sample surface treated by a two-step chemical
solution treatment (the first solution comprises 20 volume % nitric
acid combined with 25 g/L sodium dichromate, and the second
solution comprises 50 g/L sodium dichromate). Element Concentration
(in atomic %) Depth (.ANG.) O P Cr Nb B Si Ni 0 39.06 5.83 1.30
0.49 1.11 38.72 8.07 2 75.87 12.18 3.81 0.11 0.50 1.89 12.03 5
64.67 18.87 6.60 0.11 0.50 1.10 13.36 7 39.65 28.11 10.79 0.13 0.41
0.88 26.10 9 16.44 34.48 11.08 0.17 0.40 0.58 41.26 11 6.25 36.87
8.65 0.19 0.45 0.38 49.33 14 2.67 36.71 6.68 0.23 0.64 0.33 53.18
16 1.41 34.34 5.82 0.26 0.94 0.39 55.91 18 0.98 30.03 5.84 0.33
1.39 0.57 59.23 20 0.72 25.71 6.29 0.43 1.81 0.73 62.54 22 0.59
22.75 6.85 0.55 2.20 0.78 65.09 25 0.47 20.54 7.19 0.67 2.50 0.74
67.11 27 0.41 19.03 7.56 0.76 2.63 0.73 68.19 29 0.37 17.99 7.86
0.90 2.70 0.64 69.27 31 0.30 17.62 8.25 1.00 2.85 0.64 69.32 34
0.27 17.19 8.38 1.11 2.92 0.61 69.47 36 0.23 17.21 8.45 1.21 2.99
0.59 69.38 38 0.22 16.87 8.59 1.31 3.01 0.57 69.27 40 0.19 16.66
8.71 1.37 2.99 0.60 69.48 42 0.18 16.72 8.77 1.52 3.02 0.53 69.47
45 0.17 16.70 8.75 1.65 3.08 0.57 69.02 47 0.14 16.80 8.80 1.70
3.09 0.55 69.06 49 0.13 16.55 8.77 1.76 3.06 0.55 69.00 51 0.13
16.42 8.86 1.90 3.10 0.54 69.19 54 0.12 16.76 8.89 1.93 3.11 0.55
68.75 56 0.11 16.84 8.81 2.01 3.13 0.53 68.65 58 0.11 16.38 8.79
2.07 3.15 0.56 68.67 60 0.11 16.35 8.87 2.14 3.10 0.55 68.93
[0395] FIGS. 24-30 provide plots of depth profiles up to 200
angstrom for the detected elements by SIMS on the surfaces of the
as-polished sample and the sample surface treated by a two-step
chemical solution treatment (where the first solution comprises 20
volume % nitric acid combined with 25 g/L sodium dichromate, and
the second solution comprises 50 g/L sodium dichromate), including
O (FIG. 24), P (FIG. 25), Cr (FIG. 26), Nb (FIG. 27), B (FIG. 28),
Si (FIG. 29), and Ni (FIG. 30), respectively. The insets provide
plots of depth profile up to 60 angstrom for the detected elements,
and the regions for the "organic layer" of each sample are
designated by arrows.
[0396] The data in Tables 5, 10, 12, and 13 suggest that the higher
the average Cr concentration in the passive layer, the lower the Ni
ion release rate in a given solution (artificial perspiration in
the present case). The average Cr concentration in the passive
layer of untreated
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass is 4.6% (analysis of Table 10), while the Ni-ion
release rate during exposure of these rods to an artificial
perspiration solution is 1.7 .mu.g/cm.sup.2/week (Table 5). The
average Cr concentration in the passive layer of
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass rods surface treated in a sodium dichromate solution
is 4.8% (analysis of Table 12), while the Ni-ion release rate
during exposure of those rods to an artificial perspiration
solution is 0.62 .mu.g/cm.sup.2/week (Table 5). The average Cr
concentration in the passive layer of
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass rods surface treated by a two-step chemical solution
treatment is 6.2% (analysis of Table 13), while the Ni-ion release
rate during exposure of those rods to an artificial perspiration
solution is 0.032 .mu.g/cm.sup.2/week (Table 5). The Ni ion release
rate in units of .mu.g/cm.sup.2/week can be denoted as y, while the
average atomic concentration of Cr in the passive layer in units of
atomic percent can be denoted as x. These three data points reveal
that as the average atomic concentration of Cr in the passive layer
increases, the Ni ion release rate decreases.
[0397] FIG. 31 presents a plot of the logarithm of the Ni ion
release rate (log(y), on the vertical axis) against the average
atomic concentration of Cr in the passive layer in units of atomic
percent, denoted as x (on the horizontal axis). The three data
points discussed above are presented by round symbols. A fit
through the three data points is also presented by a solid line.
The fit reveals a one-to-one correspondence between log(y) and x,
suggesting a power-law correlation governed by the following
equation:
log(y)=ax+b EQ. (1)
where a=-1.0198 and b=4.8122.
[0398] In various embodiments, the Ni ion release rate in a saline
solution from a Ni-based metallic glass that has been surface
treated according to embodiments of the disclosure in a given
solution is related to the average atomic concentration of Cr in
the passive layer by a power-law according to EQ. (1), where the Ni
ion release rate is in units of .mu.g/cm.sup.2/week and the average
atomic concentration of Cr is in units of atomic percent, and where
a is between -0.5 and -5 and b is between 1 and 10. In other
embodiments, a is between -0.25 and -2.5 and b is between 2 and 8.
In yet other embodiments, a is between -0.5 and -1.5 and b is
between 3 and 7.
[0399] In contrast with Nitinol, Stainless Steel, and CoCr alloys,
the passivation of the Ni-based metallic glasses may not rely on
the formation of a stable metal oxide such as Cr.sub.2O.sub.3,
TiO.sub.2, or Nb.sub.2O.sub.5 for example. Instead, a different
mechanism involving formation of a combination of oxides and
phosphides of Cr and/or Mo is present in the current alloys. Such
compounds are likely to form on the surface of the Ni-based
metallic glasses, which would act as Ni leach barriers.
[0400] In specific examples of Cr and P bearing Ni-based metallic
glasses, such as
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
and Ni.sub.71.4Cr.sub.5.52Nb.sub.3.38P.sub.16.67B.sub.3.03 metallic
glasses, formation of a passive Ni-depleted and Cr-rich and P-rich
layer occurs as a consequence of the chemical surface treatment.
Having higher Cr content,
Ni.sub.71.4Cr.sub.5.52Nb.sub.3.38P.sub.16.67B.sub.3.03 likely forms
a more stable chromium oxide/phosphide layer and therefore
demonstrates a lower Ni-ion release rate in both treated and
untreated states.
[0401] In the specific example of Mo and P bearing Cr-free Ni-based
metallic glass, such as
Ni.sub.73.0Mo.sub.2.5Nb.sub.3.5Mn.sub.1.5P.sub.18.0Si.sub.1.5
metallic glass, formation of a passive Ni-depleted and Mo-rich and
P-rich layer may occur as a consequence of the chemical surface
treatment. The import of Cr from the chromate solution is also
likely to promote the formation a chromium oxide/phosphide layer,
which has been demonstrated here to mitigate Ni leaching.
[0402] In various embodiments, the passive layer of a sample of a
Ni-based metallic glass that has been surface treated is thicker
compared to the passive layer of an untreated sample.
[0403] In various embodiments, the average concentration of O
within the passive layer of a sample of a Ni-based metallic glass
that has been surface treated according to the disclosure is higher
compared to an untreated sample.
[0404] In various embodiments, the average concentration of Ni
within the passive layer of a sample of a Ni-based metallic glass
that has been surface treated according to the disclosure is lower
compared to an untreated sample.
[0405] In various embodiments, the average concentration of P
within the passive layer of a sample of a Ni-based metallic glass
comprising P that has been surface treated according to the
disclosure is higher compared to an untreated sample.
[0406] In various embodiments, the average concentration of Cr
within the passive layer of a sample of a Ni-based metallic glass
comprising Cr that has been surface treated according to the
disclosure is higher compared to an untreated sample.
[0407] In various embodiments, a Ni-based metallic glass that
comprises at least one of Cr and Mo, the average atomic
concentration of Cr and/or Mo within the passive layer is higher
than the respective concentrations in the inner bulk material
portion. In another embodiment, the average atomic concentration of
Cr and/or Mo within the passive layer is at least 2% higher than
the respective concentrations in the inner bulk material portion.
In another embodiment, the average atomic concentration of Cr
and/or Mo within the passive layer is at least 5% higher than the
respective concentrations in the inner bulk material portion. In
another embodiment, the average atomic concentration of Cr and/or
Mo within the passive layer is at least 10% higher than the
respective concentrations in the inner bulk material portion. In
another embodiment, the average atomic concentration of Cr and/or
Mo within the passive layer is at least 20% higher than the
respective concentrations in the inner bulk material portion.
[0408] In various embodiments, a Ni-based metallic glass that
comprises P, the average atomic concentration of P within the
passive layer is higher than the P concentration in the inner bulk
material portion. In another embodiment, the average atomic
concentration of P within the passive layer is at least 5% higher
than the P concentration in the inner bulk material portion. In
another embodiment, the average atomic concentration of P within
the passive layer is at least 10% higher than the P concentration
in the inner bulk material portion. In another embodiment, the
average atomic concentration of P within the passive layer is at
least 20% higher than the P concentration in the inner bulk
material portion. In another embodiment, the average atomic
concentration of P within the passive layer is at least 30% higher
than the P concentration in the inner bulk material portion.
[0409] Description of Methods of Producing the Alloy Ingots
[0410] The specific method used to produce the example alloy ingots
involves inductive melting of the appropriate amounts of elemental
constituents in a fused silica crucible under inert atmosphere. The
specific purity levels of the constituent elements used to create
the example alloys were as follows: Ni 99.995%, Cr 99.996%, Mo
99.95%, Mn 99.98%, Nb 99.95%, B 99.5%, P 99.9999%, and Si
99.9999%.
[0411] Description of the Method of Producing Metallic Glass
Samples
[0412] Metallic glass rods of
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
and Ni.sub.71.4Cr.sub.5.52Nb.sub.3.38P.sub.16.67B.sub.3.03 5 mm in
diameter were produced from the alloy ingots using counter-gravity
casting. In the counter-gravity casting process, molten liquid
contained in fused silica is injected upwards (against gravity)
into a mold using gas pressure. A feedstock of about 60 g was used
for each rod. An inert atmosphere was created in the melt chamber
by first applying vacuum at mbar and subsequently following several
purges with argon, an argon atmosphere was 5.times.10.sup.-2 mbar
established having a pressure of -20 in-Hg. The feedstock was
heated inductively first to 1350.degree. C. and back to
1250.degree. C. to create a homogeneous high temperature melt, and
subsequently urged upwards using an argon pressure of 10 psi
through a fused silica tube of 4 mm inner diameter into an H13 tool
steel mold fill a rod-shaped cavity with a diameter of 5 mm and
length of 100 mm. The melt was rapidly cooled in the mold to
produce an amorphous rod. The amorphicity of the rods was verified
by x-ray diffraction. The cast amorphous rods were sectioned into
10 mm-long segments. Both ends of the sectioned rods were polished
with a 1200-grit sandpaper.
[0413] Metallic glass rods of
Ni.sub.73.0Mo.sub.2.5Nb.sub.3.5Mn.sub.1.5P.sub.18.0 Si.sub.1.5 3 mm
in diameter were produced from the alloy ingots by quartz tube
casting. The method for producing metallic glass rods from the
alloy ingots involves re-melting the alloy ingots in quartz tubes
having 0.5-mm thick walls in a furnace at 1350.degree. C., under
high purity argon and rapidly quenching in a room-temperature water
bath. The cast amorphous rods were sectioned into 10 mm-long
segments. Both ends of the sectioned rods were polished with a
1200-grit sandpaper.
[0414] Description of the Methods of Chemical Surface Treatment
[0415] The Ni-based amorphous rods were subjected to the following
chemical surface treatments:
[0416] Immersion in a 10 weight % citric acid at room temperature
for 60 min.
[0417] Immersion in a 20 volume % nitric acid at room temperature
for 60 min.
[0418] Immersion in a 30 volume % nitric acid at room temperature
for 60 min.
[0419] Immersion in a 40 volume % nitric acid at room temperature
for 60 min.
[0420] Immersion in a 50 g/L sodium dichromate at 60.degree. C. for
30 min.
[0421] Immersion in a 20 volume % nitric acid combined with 44 g/L
sodium dichromate at 60.degree. C. for 30 min.
[0422] Immersion in a 40 volume % nitric acid combined with 22 g/L
sodium dichromate at 60.degree. C. for 30 min.
[0423] Immersion in a two-step treatment consisting of: (1) a 20
volume % nitric acid combined with 25 g/L sodium dichromate at
60.degree. C. for 30 min followed by water rinse, and (2) a 50 g/L
sodium dichromate at 60.degree. C. for 30 min.
[0424] Following each immersion step, the samples were thoroughly
rinsed in water and dried.
[0425] Test Methodology for Ni Extraction
[0426] Ni was extracted from rods of
Ni.sub.71.4Cr.sub.5.52Nb.sub.3.38P.sub.16.67B.sub.3.03 with a
surface area of .about.1.6 cm.sup.2 (4.5 mm-diameter and 10
mm-long) in a 1.times.PBS (Phosphate Buffered Solution) solution--a
simulated body fluid solution--for 24 hours (one day), 144 hours (6
days), and 192 hours (8 days), at 37.+-.1.degree. C. under static
condition, respectively. The solution was replaced with fresh
solution for each extraction. The same sample was used for each
time point. The PBS solution with a pH of 7.4 had a concentration
of 8.0 g/L NaCl, 0.2 g/L KCl, 1.44 g/L Na.sub.2HPO.sub.4, and 0.24
g/L KH.sub.2PO.sub.4. Ni extraction was performed in 1.6.+-.0.1 mL
of working solutions for a total of one day, 7 days, and 15 days,
at 37.+-.1.degree. C. under static condition. The solution volume
to sample surface area ratio is .about.1 mL/cm.sup.2 as recommended
by ISO standards 10993 and BS EN1811:2011.
[0427] Ni was extracted from rods of
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
with a surface area of .about.1.6 cm.sup.2 (4.5 mm-diameter and 10
mm-long) in a Fusayama/Mayer Artificial Saliva solution for 24
hours (one day), 144 hours (6 days), and 192 hours (8 days), at
37.+-.1.degree. C. under static condition, respectively. The
solution was replaced with fresh solution for each extraction. The
same sample was used for each time point. The Fusayama/Mayer
Artificial Saliva solution with a pH of 4.9 had a concentration of
0.4 g/L NaCl, 0.4 g/L KCl, 0.795 g/L CaCl.sub.2-2H.sub.2O, 0.690
g/L NaH.sub.2PO.sub.4--H.sub.2O, 0.005 g/L Na.sub.2S.9H.sub.2O, and
1 g/L Urea. Ni extraction was performed in 1.6.+-.0.1 mL of working
solutions for a total of one day, 7 days, and 15 days, at
37.+-.1.degree. C. under static condition. The solution volume to
sample surface area ratio is .about.1 mL/cm.sup.2 as recommended by
ISO standards 10993 and BS EN1811:2011.
[0428] Ni was extracted from rods of
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
with a surface area of .about.1.6 cm.sup.2 (4.5 mm-diameter and 10
mm-long) in an artificial perspiration solution. The pH of the
solution was adjusted to 6.5.+-.0.05 prior to sample immersion. The
artificial perspiration solution was prepared according to
guidelines from BS EN1811:2011, and has a concentration of 0.5%
sodium chloride, 0.1% lactic acid, and 0.1% urea. Sodium hydroxide
was added to adjust the pH, according to guidelines from BS
EN1811:2011. Ni extraction was performed in 1.6.+-.0.1 mL of
working solutions for a total of 7 days at 30.+-.2.degree. C. under
static condition. The solution volume to sample surface area ratio
is .about.1 mL/cm.sup.2 as recommended by ISO standards 10993 and
BS EN1811:2011.
[0429] Ni was extracted from rods of
Ni.sub.73.0Mo.sub.2.5Nb.sub.3.5Mn.sub.1.5P.sub.18.0Si.sub.1.5 with
a surface area of 1.0 cm.sup.2 (2.8 mm-diameter and 10 mm-long) in
an artificial perspiration solution. The pH of the solution was
adjusted to 6.5.+-.0.05 prior to sample immersion. The artificial
perspiration solution was prepared according to guidelines from BS
EN1811:2011, and has a concentration of 0.5% sodium chloride, 0.1%
lactic acid, and 0.1% urea. Sodium hydroxide was added to adjust
the pH, according to guidelines from BS EN1811:2011. Ni extraction
was performed in 1.0.+-.0.1 mL of working solutions for a total of
7 days at 30.+-.2.degree. C. under static condition. The solution
volume to sample surface area ratio is .about.1 mL/cm.sup.2 as
recommended by ISO standards 10993 and BS EN1811:2011.
[0430] Test Methodology for Assessing the Ni-Ion Release Rate
[0431] The Ni concentration in the PBS and Fusayama/Mayer
Artificial Saliva extraction solutions was analyzed by ICP-MS/AES
for 24 hours (one day), 144 hours (6 days), and 192 hours (8 days)
of immersion. The Ni in the artificial perspiration solution was
analyzed by ICP-MS/AES for 7 days of immersion. The ICP-MS/AES
instruments were calibrated with NIST traceable calibration
standards. To provide a baseline, blank samples containing only
PBS, only Fusayama/Mayer Artificial Saliva, and only artificial
perspiration solutions were also extracted.
[0432] For each time point, the Ni concentrations were calculated
using the formula:
Ni concentration (in
ppb)=(C.sub.s-C.sub.b).times.(W.sub.f/W.sub.i),
where C.sub.s is the measured concentration (ppb) in the prepared
sample solution, C.sub.b is the measured concentration (ppb) in the
prepared blank solution, W.sub.f is the final weight of the
prepared sample (g), and W, is the initial weight of the prepared
sample (g). The Ni release in ng/cm.sup.2 was then calculated by
multiplying the Ni concentration (in ppb) by the solution volume
(in mL) and dividing by the surface area of the sample (in
cm.sup.2), as follows:
Ni release ( in ng / cm 2 ) = Ni concentration ( in ppb ) .times.
solution volume ( in mL ) sample surface area ( in cm 2 ) .
##EQU00001##
[0433] In the formula above it is assumed that 1 ppb=1 ng/mL, which
is valid for an aqueous solution. Per the formula above, the weekly
Ni release in artificial perspiration extraction solution at the
end of the extraction periods of 7 days was recorded. Also, the Ni
release in PBS and Fusayama/Mayer Artificial Saliva extraction
solutions at the end of the extraction periods of 1, 6 and 8 days,
corresponding to total immersion periods of 1, 7, and 15 days, was
recorded.
[0434] In calculating daily Ni release rates in PBS and
Fusayama/Mayer Artificial Saliva extraction solutions, the average
daily Ni release rate over each extraction period was then
calculated by dividing the Ni release recorded over the extraction
period by the number of days of extraction, and is listed in Tables
1 and 3. In one example, the first extraction period was one day,
which represents a total immersion period of one day. The Ni
release recorded at the end of the first extraction period was
divided by the extraction period of one day to give the average
daily Ni release rate over the immersion period of one day, which
is listed in Tables 1 and 3. In another example, the second
extraction period was 6 days, which represents a total immersion
period of 7 days. The Ni release recorded at the end of the second
extraction period was divided by the extraction period of 6 days to
give the average daily Ni release rate over the immersion period of
2-7 days, which is listed in Tables 1 and 3. In yet another
example, the third extraction period was 8 days, which represents a
total immersion period of 15 days. The Ni release recorded at the
end of the third extraction period was divided by the extraction
period of 8 days to give the average daily Ni release rate over the
immersion period of 8-15 days, which is listed in Tables 1 and
3.
[0435] In calculating weekly Ni release rates from daily Ni release
rates in PBS and Fusayama/Mayer Artificial Saliva extraction
solutions, the weekly Ni release rate for the first week of
immersion, listed in Tables 2 and 4, was calculated by adding the
Ni release recorded at the end of the first extraction period of
one day, and the Ni release recorded at the end of the second
extraction period of 6 days. The weekly Ni release rate for the
second week of immersion, listed in Tables 2 and 4, was calculated
by adding the Ni release recorded at the end of the second
extraction period of 8 days.
[0436] Test Methodology for Assessing the Surface and in-Depth
Chemical Composition
[0437] The surface and in-depth chemical composition analysis was
performed by X-ray photoelectron spectroscopy (XPS) and electron
spectroscopy for chemical analysis (ESCA) on the cross-section area
of as-polished and surface treated
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass rod samples. XPS data is quantified using relative
sensitivity factors and a model that assumes a homogeneous layer.
The analysis volume is the product of the analysis area (spot size
or aperture size) and the depth of information. Photoelectrons are
generated within the X-ray penetration depth (typically many
microns), but only the photoelectrons within the top three
photoelectron escape depths are detected. Escape depths are on the
order of 15-35 .ANG., which leads to an analysis depth of
.about.50-100 .ANG.. Typically, 95% of the signal originates from
within this depth. Depth profiles were obtained by alternating an
acquisition cycle with a sputter cycle during which material was
removed from the sample using an Ar.sup.+ source. The sputter rate
was 50 .ANG./min relative to the SiO.sub.2 standard. The analysis
area was 1400 .mu.m.times.300 .mu.m. The concentrations of the
elements detected by XPS are provided in atomic %. Concentration
values provided are normalized to 100% using the elements detected.
The atomic concentrations provided can be reproduced for major
constituents of sample surfaces to better than .+-.10%. For
elements present at levels below 10 at % down to the detection
limit (at .about.0.05-0.5 at %; actual detection limit is element
and spectral dependent) the uncertainty in the reproducibility of
the results can be significantly larger. For elements present at
levels below 10 at %, XPS should be considered a
"semi-quantitative" analysis technique. Major factors affecting
detection limits are the element itself (heavier elements generally
have lower detection limits), interferences (can include
photoelectron peaks and Auger electron peaks from other elements)
and background (mainly caused by signal from electrons that have
lost energy to the matrix).
[0438] The surface and in-depth chemical composition analysis was
also performed by Secondary Ion Mass Spectrometry (SIMS) on the
cross-section area of as-polished and surface treated
Ni.sub.68.17Cr.sub.8.65Nb.sub.2.98P.sub.16.42B.sub.3.28Si.sub.0.5
metallic glass rod samples. SIMS provides elemental depth profiles
over a depth range of few angstrom (.ANG.) to tens of microns. The
samples are sputtered/etched with a beam of primary ions (usually O
or Cs). Secondary ions formed during the sputtering process are
extracted and analyzed using a mass spectrometer. The secondary
ions can range in concentration from matrix levels down to sub-ppm
trace levels. SIMS provides ultra-high depth resolution profiling
with detection limit and depth resolution better than
10.sup.10-10.sup.16 at/cm.sup.3 and 5 .ANG., respectively. Chemical
composition analysis of the samples was performed every 1-1.5 .ANG.
in depth. SIMS allows detection of all elements and isotopes,
including B and Si. The lateral resolution/probe size is 10 .mu.m
or better. The concentrations of the elements detected by SIMS are
provided in atomic %. SIMS is element specific, and in the context
of the present disclosure it was performed for detection of O, P,
Cr, Nb, B, Si, and Ni, while elements that contribute to the
organic layer, such as C, N, and H, were not detected. Because the
detected concentrations are element specific, i.e., not normalized
to 100% using the elements detected, summation of the
concentrations does not necessarily add up to 100%. The atomic
concentrations provided can be reproduced for major constituents of
sample surfaces.
* * * * *