U.S. patent application number 15/266286 was filed with the patent office on 2017-03-30 for micro alloying for function modification.
The applicant listed for this patent is Apple Inc.. Invention is credited to Naoto Matsuyuki, Kazuya Takagi, Yoshihiko Yokoyama.
Application Number | 20170088954 15/266286 |
Document ID | / |
Family ID | 58408552 |
Filed Date | 2017-03-30 |
United States Patent
Application |
20170088954 |
Kind Code |
A1 |
Yokoyama; Yoshihiko ; et
al. |
March 30, 2017 |
MICRO ALLOYING FOR FUNCTION MODIFICATION
Abstract
Methods and compositions of applying metallic coatings, or
altering metallic compositions, are described. Metallic coatings
are deposited on metallic substrates and treated with pulsed
radiation, such a pulsed electron beam. The resulting metal
substrate can have a metallic coating and/or altered surface
chemistry.
Inventors: |
Yokoyama; Yoshihiko; (Tokyo,
JP) ; Takagi; Kazuya; (Tokyo, JP) ; Matsuyuki;
Naoto; (Kasugai-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Apple Inc. |
Cupertino |
CA |
US |
|
|
Family ID: |
58408552 |
Appl. No.: |
15/266286 |
Filed: |
September 15, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62235096 |
Sep 30, 2015 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C23C 14/16 20130101;
C23C 28/345 20130101; C23C 14/5806 20130101; C23C 14/30 20130101;
C23C 8/10 20130101; C22C 45/10 20130101; C23C 14/0015 20130101;
C23C 8/02 20130101; C23C 28/322 20130101 |
International
Class: |
C23C 30/00 20060101
C23C030/00; C23C 8/10 20060101 C23C008/10 |
Claims
1. A method of micro-alloying a metallic glass coating onto a metal
substrate, comprising: depositing a metallic glass coating on the
metal substrate to form a metallic glass coated surface on the
metal substrate; and applying pulsed radiation to the metallic
glass coated surface to adhere the metallic glass coating to the
metal substrate to form a micro-alloyed metallic glass coated metal
substrate.
2. The method of claim 1, wherein the pulsed radiation is a pulsed
electron beam.
3. The method of claim 1, wherein the metallic glass coating
diffuses into the surface of the metal substrate.
4. The method of claim 1, wherein the metallic glass coating
diffuses in a gradient into the surface of the metal substrate.
5. The method of claim 1, wherein the micro-alloyed metallic glass
coated metal substrate exhibits surface characteristics of the
metallic glass.
6. The method of claim 1, further comprising oxidizing the
micro-alloyed metallic glass coated metal substrate.
7. The method of claim 1, wherein the metal substrate is a metallic
glass substrate.
8. The method of claim 1, wherein the application of the pulsed
radiation is controlled so as to control diffusion of the metallic
glass coating into the surface of the metal substrate.
9. A method of modifying the chemical composition of a metallic
glass comprising: depositing a metallic coating on a metallic glass
substrate to form a coated metallic glass; and applying pulsed
radiation to the coated metallic glass to form a metallic glass
substrate with altered chemical composition from the metallic glass
substrate.
10. The method of claim 9, further comprising oxidizing the
metallic glass substrate with altered chemical composition.
11. The method of claim 9, wherein the metallic glass substrate
with altered chemical composition has a different color than the
metallic glass substrate.
12. The method of claim 9, wherein the metallic glass substrate
with altered chemical composition has greater hardness than the
metallic glass substrate.
13. The method of claim 9, wherein the metallic coating is a
metallic glass coating.
14. The method of claim 9, wherein the pulsed radiation is a pulsed
electron beam.
15. A metal comprising a metallic coating diffused into a metallic
substrate.
16. The metal of claim 15, wherein the metallic substrate is a
crystalline substrate and the metallic coating is a metallic
glass.
17. The metal of claim 15, wherein the metallic glass has a
concentration gradient from the surface into the metallic
substrate.
18. The metal of claim 15, wherein the concentration gradient
extends an average of 50 microns into the metal substrate
surface.
19. The metal of claim 15, wherein both the metallic substrate and
metallic coating are a metallic glass.
20. A metallic glass coated metal substrate produced by the method
of claim 1.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This patent application claims the benefit under 35 U.S.C.
.sctn.119(e) of U.S. Patent Application No. 62/235,096, entitled
"MICRO ALLOYING FOR FUNCTION MODIFICATION," filed on Sep. 30, 2015,
which is incorporated herein by reference in its entirety.
FIELD
[0002] The disclosure relates generally to metal substrates and
related methods. More particularly, the disclosure relates to metal
substrates coated with metallic glass, and methods of coating a
metal substrate with a metallic glass.
BACKGROUND
[0003] Metallic glasses (also referred to herein as amorphous
alloys and glassy alloys) are metallic alloys that do not have a
crystalline structure. Instead, their structure is amorphous.
Metallic glasses have a number of beneficial material properties
that make them viable for use in various engineering
applications.
[0004] Metallic glasses having specific cosmetic properties can be
difficult to design. Cosmetic properties of a metal or metallic
glass are properties of the surface chemistry of the metal or
metallic glass. Further, metallic glasses can be difficult to use
as a surface coating in conventional methods.
[0005] These and other needs are provided by the present
disclosure.
SUMMARY
[0006] The present disclosure generally relates to metals
comprising a metal coating on a metal substrate and methods for
applying a metal coating onto a metal substrate using
micro-alloying.
[0007] In one aspect, the disclosure is directed to a method of
micro-alloying a metallic glass onto a metal substrate. In one
embodiment, a metallic glass coating is deposited on a metal
substrate to form a metallic glass coated surface. Pulsed radiation
is applied to the metallic glass coated surface to adhere the
metallic glass to the metal substrate. In certain variations, the
pulsed radiation is a pulsed electron beam. In some variations, the
metallic glass diffuses into the metal surface. In certain
variations, the metallic glass can form a concentration gradient in
the metal substrate surface.
[0008] In another aspect, the disclosure is directed to a method of
modifying the chemical composition of a metal substrate. In some
embodiments, the metal substrate may be a metallic glass substrate.
In some embodiments, a metallic glass coating is deposited on a
metal substrate or metallic glass substrate to form a coated
metallic glass. Pulsed radiation is applied to the coated metallic
glass to form a metallic glass with altered chemical
composition.
[0009] In certain variations of the methods described herein, the
pulsed radiation is a pulsed electron beam. In certain further
variations, the resulting metal or metallic glass has an altered
chemical composition from the original substrate. In additional
variations, the coated metal or chemically altered metallic glass
has a different color than the original metal or metallic glass
substrate. In other variations, the coated metal or chemically
altered metallic glass can have a greater hardness than the
original metal or metallic glass substrate. The metals and metallic
glasses can be further treated, such as by oxidation, to have
altered cosmetic properties.
[0010] The disclosure is also directed to metals and metallic
glasses having altered surface chemistry, as described herein.
[0011] Additional embodiments and features are set forth in part in
the description that follows, and will become apparent to those
skilled in the art upon reading of the specification. A further
understanding of the nature and advantages of the present
disclosure can be realized by reference to the remaining portions
of the specification and the drawings, which forms a part of this
disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Although the following figures and description illustrate
specific embodiments and examples, the skilled artisan will
appreciate that various changes and modifications may be made
without departing from the spirit and scope of the disclosure.
[0013] FIG. 1A depicts a schematic illustration of a metallic glass
surface coating onto a crystalline substrate using a pulsed
electron beam, in accordance with aspects of the disclosure.
[0014] FIG. 1B depicts a schematic illustration of a metallic glass
coating onto a metallic glass substrate using pulsed electron beam
radiation, in accordance with aspects of the disclosure.
[0015] FIG. 2 depicts an example of altering the color of a
metallic glass by altering the chemistry of the metallic glass, in
accordance with aspects of the disclosure.
[0016] FIG. 3 depicts formation of a dark color by depositing a Cu
metallic glass coating on a Zr-containing metallic glass substrate,
in accordance with aspects of the disclosure.
[0017] FIG. 4 depicts a portable electronic device having a
micro-alloyed metallic glass coated metal substrate on a housing
component, in accordance with aspects of the disclosure.
DETAILED DESCRIPTION
[0018] Reference will now be made in detail to representative
embodiments described herein and illustrated in the accompanying
drawings. It should be understood that the following descriptions
are not intended to limit the embodiments to one preferred
embodiment. To the contrary, it is intended to cover alternatives,
modifications, and equivalents as can be included within the spirit
and scope of the described embodiments as defined by the appended
claims.
[0019] In certain aspects, the disclosure is directed to metals
having a metallic coating on a metallic substrate and methods for
applying a metal coating onto a metal substrate using
micro-alloying. In certain embodiments, the metallic coating may be
a metallic glass coating. In other embodiments, the metallic
substrate may be crystalline or metallic glass. In certain
embodiments, the methods of the disclosure comprise micro-alloying
a metallic coating onto a metallic substrate using pulsed
radiation.
[0020] In one aspect, the disclosure is directed to a metal
substrate coated with a metallic glass, and methods of
micro-alloying a metal substrate with a metallic glass. In
accordance with the present disclosure, the metallic glass may be
applied to the metal substrate using pulsed radiation
micro-alloying, as described herein.
[0021] In certain embodiments, a metallic glass coating is
deposited on the surface of the metallic substrate. Pulsed
radiation is applied to the metallic glass coated surface. The
metallic glass adheres to, and optionally diffuses into (i.e.,
becomes part of), the metallic glass coated surface of the metallic
substrate. The resulting metallic glass coated surface can have
characteristics of metallic glass, including a harder surface than
the metallic substrate, greater corrosion resistance, and/or
altered color or texture.
[0022] FIG. 1A depicts a schematic illustration of pulsed radiation
micro-alloying in accordance with an embodiment of the disclosure.
As shown, a metallic glass surface is coated onto a crystalline
metal substrate using a pulsed electron beam. Metallic glass film
102 is deposited on the surface of a metal substrate, in this
embodiment a metal crystalline substrate 104. Pulsed radiation is
then applied to the coated surface as an electron beam. The
electron beam allows the metallic glass coating to form and adhere
to the crystalline substrate. In certain embodiments, the metallic
glass coating diffuses in the crystalline matrix of the metallic
substrate to form a mixture 106 above a crystalline portion 108 of
the metallic substrate. The resulting metallic glass coated metal
substrate can have several characteristics of metallic glasses.
These characteristics can include a harder surface, a higher
corrosion resistance, and/or color and texture modification.
[0023] In other embodiments, the disclosure is directed to a
metallic glass substrate coated with a metallic coating, and
methods of coating a metallic glass substrate with a metallic
coating. The metallic coating may be crystalline or metallic glass.
In accordance with the disclosure, a metallic coating is deposited
on a metallic glass substrate. Pulsed radiation is applied to the
coated metallic glass substrate. The metallic coating adheres to,
and optionally diffuses into (i.e., becomes part of), the metallic
glass substrate. In various embodiments, the resulting metallic
glass surface can have harder surface, greater corrosion
resistance, desired color based on oxidation of the metallic glass
coating, and/or modified texture.
[0024] FIG. 1B depicts a schematic illustration of pulsed radiation
micro-alloying in accordance with another embodiment of the
disclosure. As shown, a metallic surface is coated onto a metallic
glass substrate using a pulsed electron beam. Metal coating 110 is
deposited on metallic glass substrate 112. Both metal coating 110
and metallic glass substrate 112 have a specific chemical
composition. When pulsed radiation is applied to the coated
metallic glass substrate, the metallic coating becomes diffuses
into (i.e., becomes part of) the metallic glass substrate, to form
a metallic glass mixture 114 above a metallic glass portion 116
(metallic glass portion 116 has the same composition as the
metallic glass substrate). The surface chemistry of the resultant
metallic glass substrate has an altered chemical composition that
can have altered surface and cosmetic properties from those of the
original metallic glass substrate. As described above, metal
coating 110 may be crystalline or metallic glass.
[0025] The metallic glass can form a concentration gradient in the
metallic substrate. For example, the concentration gradient can
extend 10 microns, 20 microns, 30 microns, 40 microns, or 50
microns into the metal substrate surface. The gradient can depend
on the intensity of the pulsed radiation applied to the metallic
glass coated surface during micro-alloying.
[0026] In various additional aspects, the color of the metal
substrate can be altered by adding metallic glass to the metal
surface. By altering the chemical composition, the color of the
metal surface can be changed to that of a different alloy. Such
changes can be used to provide a single color on the metal surface,
or a different color on at different portions of the metal
surface.
[0027] Any suitable pulsed radiation source and methodology known
in the art may be used in connection with the present disclosure.
Pulsed radiation sources can include, but are not limited to,
electron beams, pulsed lasers, quartz flash lamps, and xenon arc
lamps. In particular embodiments, the pulsed radiation is a pulsed
electron beam. The pulses of radiation can be on the order of
microseconds, nanoseconds, or picoseconds. When pulsed electron
beams are used, the pulses can be on the microsecond time
scale.
[0028] Without wishing to be limited to any theory or mode of
action, the pulsed (ion/electron/laser) beam radiation allows the
metallic glass coated substrate to be heated and cooled very
rapidly. Rapid heating and cooling allows for quality improvement
of metallic glass due to both elimination of any pre-existing
crystalline component and structure rejuvenation.
[0029] In accordance with aspects of the disclosure,
characteristics of metal or metallic glass coated metal substrate
can be controlled, e.g., by controlling the composition of the
metal/metallic glass coating and/or controlling the micro-alloying
of the metal or metallic glass coating into metallic substrate. For
instance, in certain embodiments, different characteristics can be
obtained by controlling the composition of the metal/metallic glass
coating. In other embodiments, different characteristics may be
obtained by controlling the concentration of metal/metallic glass
coating diffused into the metal substrate. In this regard, the
depth of micro-alloying of the metal coating may be controlled via
controlling the thickness of the coating, controlling the duration
and/or intensity of pulsed radiation, and combinations thereof. In
certain variations, the metal coating may diffuse into the metal
substrate by a depth of at least one micron, at least two microns,
at least three microns, at least four microns, or at least five
microns.
[0030] In certain aspects of the disclosure, the thickness of the
metal or metallic glass coating and the depth of diffusion of the
metal or metallic glass coating will thereby impact the
characteristics of the metal or metallic glass coated metal
substrate. For instance, in certain embodiments, a thicker metallic
glass coating, and a deeper diffusion into the metal substrate will
result in incorporation of more characteristics of the metallic
glass coating into the metal substrate. Again, these
characteristics can include surface hardness, surface corrosion,
surface color and surface texture. It will be understood by those
skilled in the art that metallic glasses frequently have increased
surface hardness and improved surface corrosion than the equivalent
crystalline metal surface.
[0031] The metal or metallic glass coating can be in any form
suitable to apply to the metal substrate. For example, the metal or
metallic glass coating can be in the form of a film, sheet, ribbon,
pellets, or powder. In certain particular embodiments, the metal
substrate can be in the form a film.
[0032] Any metal or metallic glass substrate can be used in the
methods disclosed herein. In various embodiments, the substrate can
be any metal metallic glass substrate known in the art. Likewise,
the metallic coating can be any metal known in the art. In some
variations, the metallic coating can be crystalline. In other
variations, the metallic coating can be metallic glass.
[0033] As used herein, the terms metallic glass, metallic glass
alloy, metallic glass-forming alloy, amorphous metal, amorphous
alloy, bulk solidifying amorphous alloy, BMG alloy, and bulk
metallic glass alloy are used interchangeably.
[0034] In various embodiments, the metallic glass can be a nickel
(Ni) based alloy, iron (Fe) based alloy, copper (Cu) based alloy,
zinc (Zi) based alloy, zirconium (Zr) based alloy, gold (Au)-based
alloy, platinum (Pt) based alloy, palladium (Pd) based alloy, or
any other metallic glass. Similarly, metallic glass described
herein as a constituent of a composition or metallic glass part can
be of any type. As recognized by those of skill in the art,
metallic glasses may be selected based on and may have a variety of
potentially useful properties. In particular, metallic glasses tend
to be stronger than crystalline alloys of similar chemical
composition.
[0035] The metallic glass can comprise multiple transition metal
elements, such as at least two, at least three, at least four, or
more, transitional metal elements. The metallic glass can also
optionally comprise one or more nonmetal elements, such as one, at
least two, at least three, at least four, or more, nonmetal
elements. A transition metal element can be any of scandium,
titanium, vanadium, chromium, manganese, iron, cobalt, nickel,
copper, zinc, yttrium, zirconium, niobium, molybdenum, technetium,
ruthenium, rhodium, palladium, silver, cadmium, hafnium, tantalum,
tungsten, rhenium, osmium, iridium, platinum, gold, mercury,
rutherfordium, dubnium, seaborgium, bohrium, hassium, meitnerium,
ununnilium, unununium, and ununbium. In one embodiment, a metallic
glass containing a transition metal element can have at least one
of Sc, Y, La, Al, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe,
Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, and Hg.
Depending on the application, any suitable transitional metal
elements, or their combinations, can be used.
[0036] Depending on the application, any suitable nonmetal
elements, or their combinations, can be used. A nonmetal element
can be any element that is found in Groups 13-17 in the Periodic
Table. For example, a nonmetal element can be any one of F, Cl, Br,
I, At, O, S, Se, Te, Po, N, P, As, Sb, Bi, C, Si, Ge, Sn, Pb, and
B. Occasionally, a nonmetal element can also refer to certain
metalloids (e.g., B, Si, Ge, As, Sb, Te, and Po) in Groups 13-17.
In one embodiment, the nonmetal elements can include B, Si, C, P,
or combinations thereof. Accordingly, for example, the alloy can
comprise a boride, a carbide, or both.
[0037] In some embodiments, the metallic glass composition
described herein can be fully alloyed. The term fully alloyed used
herein can account for minor variations within the error tolerance.
For example, it can refer to at least 90% alloyed, such as at least
95% alloyed, such as at least 99% alloyed, such as at least 99.5%
alloyed, such as at least 99.9% alloyed. The percentage herein can
refer to either volume percent or weight percentage, depending on
the context. These percentages can be balanced by impurities, which
can be in terms of composition or phases that are not a part of the
alloy. The alloys can be homogeneous or heterogeneous, e.g., in
composition, distribution of elements, amorphicity/crystallinity,
etc.
[0038] The metallic glass can include any combination of the above
elements in its chemical formula or chemical composition. The
elements can be present at different weight or volume percentages.
Alternatively, in one embodiment, the above-described percentages
can be volume percentages, instead of weight percentages.
Accordingly, a metallic glass can be zirconium-based,
titanium-based, platinum-based, palladium-based, gold-based,
silver-based, copper-based, iron-based, nickel-based,
aluminum-based, molybdenum-based, and the like. The metallic glass
can also be free of any of the aforementioned elements to suit a
particular purpose. For example, in some embodiments, the metallic
glass, or the composition including the metallic glass, can be
substantially free of nickel, aluminum, titanium, beryllium, or
combinations thereof. In one embodiment, the alloy or the composite
is completely free of nickel, aluminum, titanium, beryllium, or
combinations thereof.
[0039] The afore described metallic glass can further include
additional elements, such as additional transition metal elements,
including Nb, Cr, V, and Co. The additional elements can be present
at less than or equal to about 30 wt %, such as less than or equal
to about 20 wt %, such as less than or equal to about 10 wt %, such
as less than or equal to about 5 wt %. In one embodiment, the
additional, optional element is at least one of cobalt, manganese,
zirconium, tantalum, niobium, tungsten, yttrium, titanium, vanadium
and hafnium to form carbides and further improve wear and corrosion
resistance. Further optional elements may include phosphorous,
germanium and arsenic, totaling up to about 2%, and preferably less
than 1%, to reduce melting point. Otherwise incidental impurities
should be less than about 2% and preferably 0.5%.
[0040] In some embodiments, a metallic glass composition can
include a small amount of impurities. The impurity elements can be
intentionally added to modify the properties of the composition,
such as improving the mechanical properties (e.g., hardness,
strength, fracture mechanism, etc.) and/or improving the corrosion
resistance. Alternatively, the impurities can be present as
inevitable, incidental impurities, such as those obtained as a
byproduct of processing and manufacturing. The impurities can be
less than or equal to about 10 wt %, such as about 5 wt %, such as
about 2 wt %, such as about 1 wt %, such as about 0.5 wt %, such as
about 0.1 wt %. In some embodiments, these percentages can be
volume percentages instead of weight percentages. In one
embodiment, the glassy alloy sample/composition consists
essentially of the glassy alloy (with only a small incidental
amount of impurities). In another embodiment, the composition
includes a glassy alloy (with no observable trace of
impurities).
[0041] As described above, the metal substrates or metallic glass
surfaces can have specific color characteristics as described by
the L*, a*, and b* color spectrum. These color characteristics can
be altered by the methods disclosed herein.
[0042] Color is determined by the wavelength of light that is
reflected or transmitted without being absorbed, assuming incident
light is white light. The visual appearance of objects may vary
with light reflection or transmission. In some embodiments, color
may be quantified by parameters L*, a*, and b*, where L* stands for
light brightness, a* stands for color between red and green, and b*
stands for color between blue and yellow. For example, L* values
less than 50 have a grey to black color, while L* near 0 suggest a
dark color toward the black end of the spectrum.
[0043] For color measurement, testing equipment, such as X-Rite
Color i7 XTH, X-Rite Coloreye 7000 may be used. These measurements
are according to CIE/ISO standards for illuminants, observers, and
the L* a* b* color scale. For example, the standards include: (a)
ISO 11664-1:2007(E)/CIE S 014-1/E:2006: Joint ISO/CIE Standard:
Colorimetry--Part 1: CIE Standard Colorimetric Observers; (b) ISO
11664-2:2007(E)/CIE S 014-2/E:2006: Joint ISO/CIE Standard:
Colorimetry--Part 2: CIE Standard Illuminants for Colorimetry, (c)
ISO 11664-3:2012(E)/CIE S 014-3/E:2011: Joint ISO/CIE Standard:
Colorimetry--Part 3: CIE Tristimulus Values; and (d) ISO
11664-4:2008(E)/CIE S 014-4/E:2007: Joint ISO/CIE Standard:
Colorimetry--Part 4: CIE 1976 L* a* b* Colour Space.
[0044] In some aspects, a metallic glass coating can be selected
such that the coated metal acquires a specific color. The surface
chemistry can have a specific composition corresponding to various
cosmetic properties. Alternatively, the coated metal can be
oxidized to form particular cosmetic properties.
[0045] Where the composition of a metallic or metallic glass
substrate is altered by the disclosed methods, the metallic glass
substrate can have altered properties based on the altered
elemental composition. In some aspects, the cosmetics of the
metallic glass differ from the cosmetics in the original metal
substrate or metallic glass substrate. For example, the metal
substrate can have a different color than the metallic glass coated
substrate based on the L* a* b* color scheme. In such instances,
the composition, thickness, deposition, etc. of the metallic
coating can be selected such that the micro-alloy composition of
the coated metallic substrate can be altered to a specific
chemistry.
[0046] In some variations, the metallic glass coated surface or
altered metallic glass composition can have grey to black color. In
some variations, the L* value of the alloys is from 0 to 50. In
other variations, the L* value is less than 40. In some variations,
the L* value is less than 30. In some variations, the L* value is
less than 20. In some additional variations, the L* value is less
than 10. In some aspects, the metallic glass coated surface or
altered metallic glass composition can be oxidized to form a darker
color (such as when the alloy includes darkening metals such as
Zr).
[0047] In some variations, the altered metals can have a lighter
color. In some aspects, the metallic glass coated surface or
altered metallic glass composition can be selected to have a
brighter color, for example when brightening metals such as Ir are
added. In these instances, the color of the metallic glass coated
surface or altered metallic glass composition can have an L* value
from 50 to 100. In some variations, L* is greater than 60. In some
variations, L* is greater than 70. In some variations, L* is
greater than 80. In some variations, L* is greater than 90.
[0048] In some variations, the metallic glass coated surface or
altered metallic glass composition have an a* from -10 to 10. In
some variations, the metals have an a* from -5 to 5. In further
variations, the altered metals disclosed herein have a b* from -20
to 10. In some variations, the metals have a b* from -15 to 0. In
some variations, the metals have a b* from -10 to 0.
[0049] The surface color of an alloy can be changed by altering the
chemical composition of the alloy. By adding an element and
diffusing the element into the surface, different alloying elements
can be added in different amounts to the composition. As such, in
certain aspects of the disclosure, the color of a metallic glass
can be altered by changing the elemental composition of the
metallic glass, as described herein.
[0050] In various aspects, the depth and homogeneity of the alloy
formed by pulse radiation micro-alloying can be controlled by
controlling the duration and/or intensity of the pulsed radiation.
For example, when electron beam radiation is used, the accelerate
voltage of electron beam (Vc) can be controlled, thereby
controlling the extent of the micro-alloying.
[0051] In various embodiments, other properties of coated metals or
metallic glasses can be altered by changing the chemical
composition of the metallic substrate. For example, the electrical
conductivity of metallic glasses can be increased by adding
chemically conductive elements to the coated metal or metallic
glass. In various embodiments, surface coatings such as Au, Cu,
and/or Pt group metals can be added to the metal or metallic glass
to improve electrical conductivity of the alloy. Alternatively,
metals or metallic glasses can be made more corrosion resistant by
adding a more corrosion resistant metallic glass to the surface, or
by altering the chemistry at the surface of a metallic glass using
more corrosion resistant elements. In further aspects, metallic
glass surface coatings can be used to reduce or remove of surface
incongruities of the alloy.
[0052] The methods of micro-alloying, and the metals thereby
produced, can be used in any metal containing device known in the
art. For example, methods and metals can be used in a portable
electronic device. FIG. 4 depicts a portable electronic device 400
having a micro-alloyed metallic glass coated metal substrate on a
housing component 402. In the embodiment depicted in FIG. 4, the
color of housing 402 changes between top portion 404 and bottom
portion 406. As described herein, the bottom portion 406 of
electronic device 400 appears as a darker color than top portion
404. As such, the surface of portable electronic device 400 can be
controlled by micro-alloying. FIG. 4 is not limiting. Housing
component 402 can be altered in a similar fashion, in any manner
described herein.
[0053] The methods herein can be used in the fabrication of
electronic devices using a metallic glass-containing part. An
electronic device herein can refer to any electronic device known
in the art. For example, the electronic device can be a telephone,
such as a mobile phone, and a land-line phone, or any communication
device, such as a smart phone, including, for example an
iPhone.RTM., and an electronic email sending/receiving device. The
electronic device can be a part of a display, such as a digital
display, a TV monitor, an electronic-book reader, a portable
web-browser (e.g., iPad.RTM.), and a computer monitor. The
electronic device can also be an entertainment device, including a
portable DVD player, conventional DVD player, Blue-Ray disk player,
video game console, music player, such as a portable music player
(e.g., iPod.RTM.), etc. The electronic device can also be a part of
a device that provides control, such as controlling the streaming
of images, videos, sounds (e.g., Apple TV.RTM.), or the electronic
device can be a controller (such as a remote control) for a
different electronic device. The electronic device can be a part of
a computer or its accessories, such as the hard drive tower housing
or casing, laptop housing, laptop keyboard, laptop track pad,
desktop keyboard, mouse, and speaker. The article can also be
applied to a device such as a watch or a clock.
[0054] The foregoing description, for purposes of explanation, used
specific nomenclature to provide a thorough understanding of the
described embodiments. However, it will be apparent to one skilled
in the art that the specific details are not required in order to
practice the described embodiments. Thus, the foregoing
descriptions of the specific embodiments described herein are
presented for purposes of illustration and description. They are
not target to be exhaustive or to limit the embodiments to the
precise forms disclosed. It will be apparent to one of ordinary
skill in the art that many modifications and variations are
possible in view of the above teachings.
EXAMPLES
[0055] The following non-limiting examples are provided to
illustrate aspects of the disclosure.
Example 1
[0056] By way of example, FIG. 2 depicts an example of altering a
color parameter by altering the chemistry of the metallic glass
using the disclosed methods. FIG. 2 shows the relationship between
the alloy composition parameter of Zr/Cu ratio and parameter b* in
Lab color space.
[0057] LM-105 and LM-601 are commercialized bulk metallic glasses,
and Experimental Alloy 1 and Experimental Alloy 2 are
Zr.sub.50Cu.sub.40Al.sub.10 and Zr.sub.60Cu.sub.30Al.sub.10
metallic glasses, respectively. Alloy LM-105 differs from alloy
LM-601 based on the molar ratio of Zr/Cu. A surface coating of Cu
was then added to the surface of the metallic glass substrate and
electron beam radiation was applied to micro-alloy the Cu coating
in accordance with the present disclosure. After application of the
electron beam radiation on the surface, the Zr/Cu ratio was further
reduced by the addition of Cu coating. As shown in FIG. 2, as Zr/Cu
ratio decreases, the measure of b* was reduced from approximately
-18.00 to less than -2.00. In this regard, it was found that an
optimized range for Zr/Cu to obtain a dark color (a b* value of
about 0) may generally be in the range of about 1.1 to about
1.5.
[0058] In various aspects, the color of the metal or metallic glass
can be formed with or without oxidizing the metal.
Example 2
[0059] In another example, FIG. 3 depicts formation of a dark color
by depositing Cu on a Zr-containing metallic glass substrate. In
FIG. 3, 100 nm, 500 nm, and 1000 nm of copper were deposited on a
metallic glass substrate. FIG. 3 shows the color change obtained by
micro-alloying in accordance with the present disclosure after
oxidization annealing in air (380.degree. C., 1 hr). The Vc of the
pulsed electron beam was controlled to insure the homogeneity of
the resulting surface alloy. By using 100 nm Cu plating thick and
an electron beam at Vc of 30 kV, a darker surface was obtained. No
luster was observed on the surface when 500 nm or 1000 nm Cu film
were deposited and an electron beam at Vc 20 kV was used. By
balancing the amounts of deposited metal and electron beam power,
the chemical composition and resulting properties of the metallic
glass could be controlled.
[0060] While this disclosure has been described with reference to
specific embodiments, it will be understood by those skilled in the
art that various changes may be made and equivalents may be
substituted for elements thereof, without departing from the spirit
and scope of the disclosure. In addition, modifications may be made
to adapt the teachings of the disclosure to particular situations
and materials, without departing from the essential scope thereof.
Thus, the disclosure is not limited to the particular examples that
are disclosed herein, but encompasses all embodiments falling
within the scope of the appended claims.
* * * * *