U.S. patent application number 11/254821 was filed with the patent office on 2006-02-23 for nano invar alloys and process for producing the same.
This patent application is currently assigned to Nano Invar Co., Ltd.. Invention is credited to Yong Bum Park.
Application Number | 20060037671 11/254821 |
Document ID | / |
Family ID | 33308297 |
Filed Date | 2006-02-23 |
United States Patent
Application |
20060037671 |
Kind Code |
A1 |
Park; Yong Bum |
February 23, 2006 |
Nano invar alloys and process for producing the same
Abstract
The present invention relates to an electrolyte for producing a
novel Fe--Ni alloy having an Ni content in a range of 33 to 42 wt
%, specifically a nanocrystalline invar alloy having a grain size
of 5 to 15 nm, by electroplating, and preparation conditions
thereof. The electrolyte comprises, on the basis of 1 L of water,
32 to 53 g of ferrous sulfate or ferrous chloride, a mixture
thereof; 97 g of nickel sulfate, nickel chloride, nickel sulfamate
or a mixture thereof; 20 to 30 g of boric acid; 1 to 3 g of sodium
saccharin; 0.1 to 0.3 g of sodium lauryl sulfate; and 20 to 40 g of
sodium chloride. The Fe--Ni alloy sheet of the present invention
exhibits excellent mechanical property compared to the conventional
Fe--Ni alloy and a new property, i.e., a negative coefficient of
thermal expansion at a given temperature range.
Inventors: |
Park; Yong Bum;
(Gyeonggi-do, KR) |
Correspondence
Address: |
BACON & THOMAS, PLLC
625 SLATERS LANE
FOURTH FLOOR
ALEXANDRIA
VA
22314
US
|
Assignee: |
Nano Invar Co., Ltd.
Seoul
KR
|
Family ID: |
33308297 |
Appl. No.: |
11/254821 |
Filed: |
October 21, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/KR04/00516 |
Mar 12, 2004 |
|
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|
11254821 |
Oct 21, 2005 |
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Current U.S.
Class: |
148/336 ;
205/365; 205/557; 420/94 |
Current CPC
Class: |
C25D 3/562 20130101 |
Class at
Publication: |
148/336 ;
420/094; 205/365; 205/557 |
International
Class: |
C22C 38/08 20060101
C22C038/08; C25C 1/24 20060101 C25C001/24 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 24, 2003 |
KR |
10-2003-0026108 |
Claims
1. An Fe--Ni alloy containing 33% to 38% by weight of Ni, produced
by electroplating, using a solution as an electrolyte, on the basis
of 1 liter (L) of water, comprising 32 to 53 g of ferrous sulfate
(FeSO.sub.4.7H.sub.2O), ferrous chloride (FeCl.sub.2.4H.sub.2O) or
a mixture thereof; 97 g of nickel sulfate (NiSO.sub.4.6H.sub.2O),
nickel chloride (NiCl.sub.2.6H.sub.2O), nickel sulfamate
(Ni(NH.sub.2SO.sub.3).sub.2) or a mixture thereof; 20 to 30 g of
boric acid (H.sub.3BO.sub.3); 1 to 3 g of sodium saccharin
(C.sub.7H.sub.4NO.sub.3SNa); 0.1 to 0.3 g of sodium lauryl sulfate
(C.sub.12H.sub.25O.sub.4SNa); and 20 to 40 g of sodium chloride
(NaCl), under the conditions of a pH of the electrolyte being in a
range of 2 to 3, a current density being in a range of 50 to 100
mA/cm.sup.2, and a temperature of the electrolyte being in a range
of 45 to 60.degree. C.
2. The Fe--Ni alloy of claim 1, wherein the electrolyte, on the
basis of 1 L of water, comprises: 43 to 53 g of ferrous sulfate
(FeCl.sub.2.4H.sub.2O); 97 g of nickel sulfate
(NiSO.sub.4.6H.sub.2O); 20 to 30 g of boric acid (H.sub.3BO.sub.3);
1.0 to 3.0 g of sodium saccharin (C.sub.7H.sub.4NO.sub.3SNa); 0.1
to 0.3 g of sodium lauryl sulfate (C.sub.12H.sub.25O.sub.4SNa); and
20 to 40 g of sodium chloride (NaCl).
3. The Fe--Ni alloy of claim 1, wherein the electrolyte, on the
basis of 1 L of water, comprises: 50 g of ferrous sulfate
(FeSO.sub.4.7H.sub.2O); 97 g of nickel chloride
(NiCl.sub.2.6H.sub.2O); 20 to 30 g of boric acid (H.sub.3BO.sub.3);
1.0 to 3.0 g of sodium saccharin (C.sub.7H.sub.4NO.sub.3SNa); 0.1
to 0.3 g of sodium lauryl sulfate (C.sub.12H.sub.25O.sub.4SNa); and
20 to 40 g of sodium chloride (NaCl).
4. The Fe--Ni alloy of claim 1, wherein the electrolyte, on the
basis of 1 L of water, comprises: 42 to 44 g of ferrous chloride
(FeCl.sub.4.4H.sub.2O); 97 g of nickel sulfate
(NiSO.sub.4.6H.sub.2O); 20 to 30 g of boric acid (H.sub.3BO.sub.3);
1.0 to 3.0 g of sodium saccharin (C.sub.7H.sub.4NO.sub.3SNa); 0.1
to 0.3 g of sodium lauryl sulfate (C.sub.12H.sub.25O.sub.4SNa); and
20 to 40 g of sodium chloride (NaCl).
5. The Fe--Ni alloy of claim 1, wherein the electrolyte, on the
basis of 1 L of water, comprises: 44 to 50 g of ferrous chloride
(FeCl.sub.4.4H.sub.2O); 97 g of nickel chloride
(NiCl.sub.2.6H.sub.2O); 20 to 30 g of boric acid (H.sub.3BO.sub.3);
1.0 to 3.0 g of sodium saccharin (C.sub.7H.sub.4NO.sub.3SNa); 0.1
to 0.3 g of sodium lauryl sulfate (C.sub.12H.sub.25O.sub.4SNa); and
20 to 40 g of sodium chloride (NaCl).
6. The Fe--Ni alloy of claim 1, wherein the electrolyte, on the
basis of 1 L of water, comprises: 35 to 37 g of ferrous sulfate
(FeSO.sub.4.7H.sub.2O); 97 g of nickel sulfamate
(Ni(NH.sub.2SO.sub.3).sub.2); 20 to 30 g of boric acid
(H.sub.3BO.sub.3); 1.0 to 3.0 g of sodium saccharin
(C.sub.7H.sub.4NO.sub.3SNa); 0.1 to 0.3 g of sodium lauryl sulfate
(C.sub.12H.sub.25O.sub.4SNa); and 20 to 40 g of sodium chloride
(NaCl).
7. The Fe--Ni alloy of claim 1, wherein the electrolyte, on the
basis of 1 L of water, comprises: 32 to 34 g of ferrous chloride
(FeCl.sub.4.4H.sub.2O); 97 g of nickel sulfamate
(Ni(NH.sub.2SO.sub.3).sub.2); 20 to 30 g of boric acid
(H.sub.3BO.sub.3); 1.0 to 3.0 g of sodium saccharin
(C.sub.7H.sub.4NO.sub.3SNa); 0.1 to 0.3 g of sodium lauryl sulfate
(C.sub.12H.sub.25O.sub.4SNa); and 20 to 40 g of sodium chloride
(NaCl).
8. The Fe--Ni alloy of any one of claims 1 through 7, wherein the
Fe--Ni alloy has a thickness in a range of 1 to 200 .mu.m.
9. The Fe--Ni alloy of any one of claims 1 through 7, wherein the
Fe--Ni alloy has a grain size in a range of 5 to 15 nm.
10. The Fe--Ni alloy of any one of claims 1 through 7, wherein the
Fe--Ni alloy has a negative coefficient of thermal expansion at a
predetermined temperature or higher.
11. The Fe--Ni alloy of any one of claims 1 through 8, wherein the
Fe--Ni alloy has a composition ratio of 64 wt % Fe and 36 wt %
Ni.
12. A method of producing an Fe--Ni alloy containing 33% to 38% by
weight of Ni, comprising carrying out electroplating, using a
solution as an electrolyte, on the basis of 1 liter (L) of water,
comprising 32 to 53 g of ferrous sulfate (FeSO.sub.4.7H.sub.2O),
ferrous chloride (FeCl.sub.2.4H.sub.2O) or a mixture thereof; 97 g
of nickel sulfate (NiSO.sub.4.6H.sub.2O), nickel chloride
(NiCl.sub.2.6H.sub.2O), nickel sulfamate
(Ni(NH.sub.2SO.sub.3).sub.2) or a mixture thereof; 20 to 30 g of
boric acid (H.sub.3BO.sub.3); 1 to 3 g of sodium saccharin
(C.sub.7H.sub.4NO.sub.3SNa); 0.1 to 0.3 g of sodium lauryl sulfate
(C.sub.12H.sub.25O.sub.4SNa); and 20 to 40 g of sodium chloride
(NaCl), under the conditions of a pH of the electrolyte being in a
range of 2 to 3, a current density being in a range of 50 to 100
mA/cm.sup.2, and a temperature of the electrolyte being in a range
of 45 to 60.degree. C.
13. The method of claim 12, wherein the electrolyte, on the basis
of 1 L of water, comprises: 43 to 53 g of ferrous sulfate
(FeSO.sub.4.7H.sub.2O); 97 g of nickel sulfate
(NiSO.sub.4.6H.sub.2O); 20 to 30 g of boric acid (H.sub.3BO.sub.3);
1.0 to 3.0 g of sodium saccharin (C.sub.7H.sub.4NO.sub.3SNa); 0.1
to 0.3 g of sodium lauryl sulfate (C.sub.12H.sub.25O.sub.4SNa); and
20 to 40 g of sodium chloride (NaCl).
14. The method of claim 12, wherein the electrolyte, on the basis
of 1 L of water, comprises: 50 g of ferrous sulfate
(FeSO.sub.4.7H.sub.2O); 97 g of nickel chloride
(NiCl.sub.2.6H.sub.2O); 20 to 30 g of boric acid (H.sub.3BO.sub.3);
1.0 to 3.0 g of sodium saccharin (C.sub.7H.sub.4NO.sub.3SNa); 0.1
to 0.3 g of sodium lauryl sulfate (C.sub.12H.sub.25O.sub.4SNa); and
20 to 40 g of sodium chloride (NaCl).
15. The method of claim 12, wherein the electrolyte, on the basis
of 1 L of water, comprises: 42 to 44 g of ferrous chloride
(FeCl.sub.4.4H.sub.2O); 97 g of nickel sulfate
(NiSO.sub.4.6H.sub.2O); 20 to 30 g of boric acid (H.sub.3BO.sub.3);
1.0 to 3.0 g of sodium saccharin (C.sub.7H.sub.4NO.sub.3SNa); 0.1
to 0.3 g of sodium lauryl sulfate (C.sub.12H.sub.25O.sub.4SNa); and
20 to 40 g of sodium chloride (NaCl).
16. The method of claim 12, wherein the electrolyte, on the basis
of 1 L of water, comprises: 44 to 50 g of ferrous chloride
(FeCl.sub.4.4H.sub.2O); 97 g of nickel chloride
(NiCl.sub.2.6H.sub.2O); 20 to 30 g of boric acid (H.sub.3BO.sub.3);
1.0 to 3.0 g of sodium saccharin (C.sub.7H.sub.4NO.sub.3SNa); 0.1
to 0.3 g of sodium lauryl sulfate (C.sub.12H.sub.25O.sub.4SNa); and
20 to 40 g of sodium chloride (NaCl).
17. The method of claim 12, wherein the electrolyte, on the basis
of 1 L of water, comprises: 35 to 37 g of ferrous sulfate
(FeSO.sub.4.7H.sub.2O); 97 g of nickel sulfamate
(Ni(NH.sub.2SO.sub.3).sub.2); 20 to 30 g of boric acid
(H.sub.3BO.sub.3); 1.0 to 3.0 g of sodium saccharin
(C.sub.7H.sub.4NO.sub.3SNa); 0.1 to 0.3 g of sodium lauryl sulfate
(C.sub.12H.sub.25O.sub.4SNa); and 20 to 40 g of sodium chloride
(NaCl).
18. The method of claim 12, wherein the electrolyte, on the basis
of 1 L of water, comprises: 32 to 34 g of ferrous chloride
(FeCl.sub.2.4H.sub.2O); 97 g of nickel sulfamate
(Ni(NH.sub.2SO.sub.3).sub.2); 20 to 30 g of boric acid
(H.sub.3BO.sub.3); 1.0 to 3.0 g of sodium saccharin
(C.sub.7H.sub.4NO.sub.3SNa); 0.1 to 0.3 g of sodium lauryl sulfate
(C.sub.12H.sub.25O.sub.4SNa); and 20 to 40 g of sodium chloride
(NaCl).
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation-In-Part of PCT
International Application No. PCT/KR2004/000516 filed on Mar. 12,
2004, which designated the United States.
FIELD OF THE INVENTION
[0002] The present invention relates to an electrolyte for
producing a novel Fe--Ni alloy having a Ni content in a range of 33
to 42 wt %, specifically a nanocrystalline invar alloy having a
grain size of 5 to 15 nm, by electroplating, and preparation
conditions thereof.
BACKGROUND OF THE INVENTION
[0003] Fe--Ni alloys exhibit various properties according to the Ni
content, and low thermal expansion properties are exhibited when
the Ni content is in a range of 20% to 50% by weight (see D. R.
Rancourt, S. Chehab and G. Lamarche, J. Mag. Mag. Mater. 78 (1989)
129.). Specifically, an alloy consisting of 64% Fe and 36% Ni,
which is referred to as "an invar alloy", has a coefficient of
thermal expansion of about zero. The invar alloy has, since its
discovery in 1897 by Guillaume (see C. E. Guillaume, C.R. Acad.
Sci. Paris 124 (1897) 176.), been commercially used for various
practical applications as a typical low thermal expansion
alloy.
[0004] Such a typical low thermal expansion invar alloy (Fe-36% Ni)
is used in a variety of applications, such as a standard
measurement apparatus, an internal combustion engine piston,
bimetal, a temperature controller, a liquefied gas storage device,
an IC lead frame, a shadow mask, which is an essential component of
a cathode ray tube(CRT) for a color monitor of a TV or PC, other
electronic devices, or the like.
[0005] Also, a shadow mask made of invar alloys is expected to be
used not only in field emission displays (FEDs) for flat monitors,
which have recently been developed, but also in lead frames for
mounting integrated circuit(IC) chips.
[0006] There may be circumstances where alloys need to be
shrinkable as the temperature at which the alloys are used,
increases. In such case, development of alloys having a negative
coefficient of thermal expansion in an operating temperature range
is very highly demanded.
[0007] Various processes have been employed to produce the Fe--Ni
alloy sheets, and cold rolling has been typically used for that
purpose. When conducting the cold rolling, vacuum melting, forging,
hot rolling, normalizing, primary cold rolling, intermediate
annealing, secondary cold rolling, final annealing under a
reduction atmosphere and so on should be performed. In order to
produce a thin invar alloy sheet having a thickness of 0.1 mm or
less, it is necessary to carry out a multi-stage rolling process,
as disclosed in U.S. Pat. No. 4,94,834, which is, however, complex,
and makes it difficult to obtain homogenous product. Also, this
process undesirably requires a high production cost. Furthermore,
there are several problems that large-scale equipment, such as a
vacuum melting furnace, forging facility, a hot roller or a
multi-stage roller, is required, and a heating process for shaping
as requested by final product is quite difficult to perform etc.
Further, coefficients of thermal expansion are undesirably
sensitive to impurities involving in the process and a change in
the processing conditions (see Metals Handbook, 9th ed. Vol. 3, ASM
(1980) 889.).
[0008] To overcome the limitations of the conventional preparation
methods, vigorous research into preparation methods of Fe--Ni
alloys by electroplating electroforming) has been carried out in
recent years. However, according to the electroplating, since
selecting a proper electrolyte or establishing proper processing
conditions, such as a temperature or current density, are quite
complicated, the use of electroplating for producing desired Fe--Ni
alloys has not been successful.
SUMMARY OF THE INVENTION
[0009] Therefore, there is an increasing demand for providing
proper electrolytes and processing conditions for producing nano
invar alloys. In particular, since a sheet to be plated should have
a width of at least 300 mm (30 cm) for commercial use, it is
necessary to find out appropriate conditions for electroplating
under such circumstances.
[0010] It is an object of the present invention to provide an
electrolyte for producing a nano invar alloy sheet having a
nano-scale grain size by electroplating or electroforming, and
processing conditions thereof.
[0011] It is another object of the present invention to provide an
Fe--Ni alloy having a negative coefficient of thermal expansion at
a given temperature range.
[0012] It is still another object of the present invention to
provide an Fe--Ni alloy having excellent mechanical properties
compared to the conventional invar alloy.
[0013] It is yet another object of the present invention to provide
a method for producing an Fe--Ni alloy having a negative
coefficient of thermal expansion at a given temperature range.
[0014] In accordance with the present invention, there is provided
an Fe--Ni alloy containing 33% to 38% by weight of Ni, produced by
electroplating, using a solution as an electrolyte, on the basis of
1 liter (L) of water, comprising 32 to 53 g of ferrous sulfate
(FeSO.sub.4.7H.sub.2O), ferrous chloride (FeCl.sub.2.4H.sub.2O) or
a mixture thereof; 97 g of nickelsulfate (NiSO.sub.4.6H.sub.2O),
nickel chloride (NiCl.sub.2.6H.sub.2O), nickel sulfamate
(Ni(NH.sub.2SO.sub.3).sub.2) or a mixture thereof; 20 to 30 g of
boric acid (H.sub.3BO.sub.3); 1 to 3 g of sodium saccharin
(C.sub.7H.sub.4NO.sub.3SNa); 0.1 to 0.3 g of sodium lauryl sulfate
(C.sub.12H.sub.25O.sub.4SNa); and 20 to 40 g of sodium chloride
(NaCl), under the conditions that a pH of the electrolyte is in a
range of 2 to 3, a current density is in a range of 50 to 100
mA/cm.sup.2, and a temperature of the electrolyte is in a range of
45 to 60.degree. C.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The above and other features and advantages of the present
invention will become more apparent by describing in detail
exemplary embodiments thereof with reference to the attached
drawings in which:
[0016] FIG. 1 is a schematic diagram of an electroplating apparatus
for producing a nano invar alloy sheet according to the present
invention;
[0017] FIG. 2 illustrates a change in the coefficient of thermal
expansion depending on the composition ratio of a nano invar alloy
according to the present invention;
[0018] FIG. 3 is a {111} pole figure of texture after annealing a
conventional invar alloy;
[0019] FIG. 4 is a {100} pole figure of texture of the nano invar
alloy according to the present invention; and
[0020] FIG. 5 is a {111} pole figure of texture after annealing the
nano invar alloy according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] A preferred embodiment of the present invention will now be
described in detail with reference to the accompanying
drawings.
[0022] FIG. 1 is a schematic diagram of an electroplating apparatus
for producing a nano invar alloy sheet according to the present
invention.
[0023] In FIG. 1, electroplating was conducted such that an
electrolyte 3 according to the present invention was put in an
electroplating bath 9, and a circulation pump 5 was actuated to
allow the electrolyte 3 to flow between a cathode 1 and an anode 2,
spaced 10 mm apart from each other, at a flow rate of 0.1 to 2.0
m/sec. Here, reference numeral 6 denotes a circulation pipe. When a
20 .mu.m thick Fe--Ni alloy was electrodeposited on a cathode
sheet, a current supply device 4 was stopped operating, and a
resulting electroplated sheet was isolated from a cathode surface.
According to an aspect of the present invention, the inclination 10
of an anode sheet depends on the flow rate.
[0024] The electrolyte proposed in the present invention is a
solution having a composition comprising ferrous sulfate
(FeSO.sub.4.7H.sub.2O) or ferrous chloride (FeCl.sub.2.4H.sub.2O);
nickel sulfate (NiSO.sub.4.6H.sub.2O), nickel chloride
(NiCl.sub.2.6H.sub.2O) or nickel sulfamate
(Ni(NH.sub.2SO.sub.3).sub.2); 20 to 30 g/l of boric acid
(H.sub.3BO.sub.3); 1 to 3 g/l of sodium saccharin
(C.sub.7H.sub.4NO.sub.3SNa); 0.1 to 0.3 g/l of sodium lauryl
sulfate (C.sub.12H.sub.25O.sub.4SNa); and 20 to 40 g/l of sodium
chloride (NaCl). More desirable effects of the electrolyte are
achieved by comprising 22 to 25 g/l of boric acid
(H.sub.3BO.sub.3), 2.0 to 2.4 g/l of sodium saccharin
(C.sub.7H.sub.4NO.sub.3SNa), 0.1 to 0.2 g/l of sodium lauryl
sulfate pH buffering agent, sodium sacchanrin is added as a stress
relaxing agent for the electroplated product, sodium chloride is
added for the purpose of enhancing the conductivity of the
electrolyte, and sodium lauryl sulfate is added as a surfactant.
During electroplating, the pH of the electrolyte is maintained in a
range of 2 to 3, the current density is in a range of 50 to 100
mA/cm.sup.2, and the temperature of the electrolyte is in a range
of 45 to 60.degree. C.
[0025] The Fe component and Ni component are released in the ionic
form from the electrolyte and are electrodeposited on a cathode
sheet in the form of Fe--Ni alloy having a thickness of 1 to 200
.mu.m during electroplating.
[0026] Tables 1 through 6 show examples of electrolytes for
producing nano invar alloy sheets of the present invention by
electroplating. TABLE-US-00001 TABLE 1 Using solution containing
ferrous sulfate (FeSO.sub.4.7H.sub.2O) and nickel sulfate
(NiSO.sub.4.6H.sub.2O) Ni of the FeSO.sub.4. NiSO.sub.4.
C.sub.12H.sub.25O.sub.4S C.sub.7H.sub.4NO.sub.3 Fe-Ni 7H.sub.2O
6H.sub.2O H.sub.3BO.sub.3 Na SNa NaCl Fe:Ni alloy Example (g) (g)
(g) (g) (g) (g) (mol) (wt %) 1 43 97 22 0.1 2.0 32 1:2.371 38.8 2
48 97 22 0.1 2.0 32 1:2.124 36.4 3 53 97 22 0.1 2.0 32 1:1.923 34.2
<On the basis of 1 liter of distilled water>
[0027] TABLE-US-00002 TABLE 2 Using solution containing ferrous
sulfate (FeSO.sub.4.7H.sub.2O) and nickel chloride
(NiCl.sub.2.6H.sub.2O) Ni of the FeSO.sub.4. NiCl.sub.2.
C.sub.12H.sub.25O.sub.4S C.sub.7H.sub.4NO.sub.3 Fe-Ni 7H.sub.2O
6H.sub.2O H.sub.3BO.sub.3 Na SNa NaCl Fe:Ni alloy Example (g) (g)
(g) (g) (g) (g) (mol) (wt %) 4 50 97 22 0.1 2.0 32 1:2.039 36.6
<On the basis of 1 liter of distilled water>
[0028] TABLE-US-00003 TABLE 3 Using solution containing ferrous
chloride (FeCl.sub.2.4H.sub.2O) and nickel sulfate
(NiSO.sub.4.6H.sub.2O) Ni of the FeCl.sub.2. NiSO.sub.4.
C.sub.12H.sub.25O.sub.4S C.sub.7H.sub.4NO.sub.3 Fe-Ni 4H.sub.2O
6H.sub.2O H.sub.3BO.sub.3 Na SNa NaCl Fe:Ni alloy Example (g) (g)
(g) (g) (g) (g) (mol) (wt %) 5 42 97 22 0.1 2.0 32 1:2.832 37.5 6
44 97 22 0.1 2.0 32 1:2.427 36.2 <On the basis of 1 liter of
distilled water>
[0029] TABLE-US-00004 TABLE 4 Using solution containing ferrous
chloride (FeCl.sub.2.4H.sub.2O) and nickel chloride
(NiCl.sub.2.6H.sub.2O) Ni of the FeSO.sub.4. NiCl.sub.2.
C.sub.12H.sub.25O.sub.4S C.sub.7H.sub.4NO.sub.3 Fe-Ni 7H.sub.2O
6H.sub.2O H.sub.3BO.sub.3 Na SNa NaCl Fe:Ni alloy Example (g) (g)
(g) (g) (g) (g) (mol) (wt %) 7 44 97 22 0.1 2.0 32 1:2.317 38.3 8
46 97 22 0.1 2.0 32 1:2.216 36.2 9 50 97 22 0.1 2.0 32 1:2.039 32.7
<On the basis of 1 liter of distilled water>
[0030] TABLE-US-00005 TABLE 5 Using solution containing ferrous
sulfate (FeSO.sub.4.7H.sub.2O) and nickel sulfamate (Ni
(NH.sub.2SO.sub.3).sub.2) Ni of the FeSO.sub.4. Ni (NH.sub.2
C.sub.12H.sub.25O.sub.4 C.sub.7H.sub.4NO.sub.3 Fe-Ni 7H.sub.2O
SO.sub.3).sub.2 H.sub.3BO.sub.3 SNa SNa NaCl Fe:Ni alloy Example
(g) (g) (g) (g) (g) (g) (mol) (wt %) 10 35 97 22 0.1 2.0 32 1:2.913
36.3 11 37 97 22 0.1 2.0 32 1:2.755 34.5 <On the basis of 1
liter of distilled water>
[0031] TABLE-US-00006 TABLE 6 Using solution containing ferrous
chloride (FeCl.sub.2.4H.sub.2O) and nickel sulfamate (Ni
(NH.sub.2SO.sub.3).sub.2) Ni of the FeCl.sub.2. Ni (NH.sub.2
C.sub.12H.sub.25O.sub.4 C.sub.7H.sub.4NO.sub.3 Fe-Ni 7H.sub.2O
SO.sub.3).sub.2 H.sub.3BO.sub.3 SNa SNa NaCl Fe:Ni alloy Example
(g) (g) (g) (g) (g) (g) (mol) (wt %) 12 32 97 25 0.2 2.4 30 1:3.186
37.0 13 34 97 25 0.2 2.4 30 1:2.998 35.2 <On the basis of 1
liter of distilled water>
[0032] Table 1 shows preparation results of Fe--Ni alloys having
desired compositions according to Examples 1 through 3 using
electrolytes containing ferrous sulfate (FeSO.sub.4.7H.sub.2O) and
nickel sulfate (NiSO.sub.4.6H.sub.2) as main components, with
keeping the amounts of nickel sulfate at 97 g/l and varying the
amounts of ferrous sulfate in a range of 43 to 53 g/l.
[0033] Table 2 shows a preparation result of an Fe--Ni alloy having
a desired composition according to Example 4 using an electrolyte
containing ferrous sulfate (FeSO.sub.4.7H.sub.2O) and nickel
chloride (NiCl.sub.2.6H.sub.2O) as main components, with keeping
the amount of nickel sulfate at 97 g/l and using 50 g/l of ferrous
sulfate.
[0034] Table 3 shows preparation results of Fe--Ni alloys having
desired compositions according to Examples 5 and 6 using
electrolytes containing ferrous chloride (FeCl.sub.2.4H.sub.2O) and
nickel sulfate(NiSO.sub.4.6H.sub.2O) as main components, with
keeping the amounts of nickel sulfate at 97 g/l and varying the
amounts of ferrous chloride in a range of 42 to 44 g/l.
[0035] Table 4 shows preparation results of Fe--Ni alloys having
desired compositions according to Examples 7 and 9 using
electrolytes containing ferrous chloride (FeCl.sub.2.4H.sub.2O) and
nickel chloride (NiCl.sub.2.6H.sub.2O) as main components, with
keeping the amounts of nickel chloride at 97 g/l and varying the
amounts of ferrous chloride in a range of 44 to 50 g/l.
[0036] Table 5 shows preparation results of Fe--Ni alloys having
desired compositions according to Examples 10 and 11 using
electrolytes containing ferrous sulfate (FeSO.sub.4.7H.sub.2O) and
nickel sulfamate (Ni(NH.sub.2SO.sub.3).sub.2) as main components,
with keeping the amounts of nickel sulfamate at 97 g/l and varying
the amounts of ferrous sulfate in a range of 35 to 37 g/l.
[0037] Table 6 shows preparation results of Fe--Ni alloys having
desired compositions according to Examples 12 and 13 using
electrolytes containing ferrous chloride (FeCl.sub.2.4H.sub.2O) and
nickel sulfamate (Ni(NH.sub.2SO.sub.3).sub.2) as main components,
with keeping the amounts of nickel sulfamate at 97 g/l and varying
the amounts of ferrous chloride in a range of 32 to 34 g/l.
[0038] The Fe--Ni alloys produced using the electrolytes having the
compositions listed above by electroplating, have properties shown
in Table 8 below, irrespective of kinds of electrolytes used in
Tables 1 through 6. When comparing the conventional invar alloys
shown in Table 7 with the nano invar alloys according to the
present invention in view of their properties, it is confirmed that
the nano invar alloys according to the present invention have
better material characteristics than the conventional invar alloys.
The comparison results are shown in Table 9. TABLE-US-00007 TABLE 7
Physical properties of conventional invar alloys Density,
g/cm.sup.3 8.1 Tensile strength, MPa 450-585 Yield strength, MPa
275.about.415 Elastic limit, MPa 140-205 Elongation, % 30.about.45
Reduction in area, % 55.about.70 Brinell hardness 160 Modulus of
elasticity, GPa (10.sup.6 psi) 150(21.4) Thermoelastic coefficient,
mm/m k 500 Specific heat, at 25.about.100.degree. C., J/kg .degree.
C. 515 Thermal conductivity, at 20-100.degree. C., W/m k 11
Electrical resistivity, ml m 750.about.850
[0039] TABLE-US-00008 TABLE 8 Physical properties of nano invar
alloys according to the present invention Hardness, GPa 5.4 Tensile
strength, MPa 1,045 Yield strength, MPa 805 Modulus of elasticity,
GPa 85.about.120
[0040] TABLE-US-00009 TABLE 9 Comparison between conventional invar
alloys and nano invar alloys according to the present invention in
view of the properties Conventional invar alloy (Commercially
available Nano invar alloy invar alloy) (Present invention)
Hardness 2.5 GPa 5.4 GPa Tensile 450.about.585 MPa 1,045 MPa
strength Yield 275.about.415 MPa 805 MPa strength
[0041] In other words, the nano invar alloy according to the
present invention is at least two times higher than the
conventional invar alloy in view of hardness, tensile strength, and
yield strength. In detail, the yield strength of the nano invar
alloys according to the present invention is 805 MPa, which is much
higher than that of the conventional invar alloy, that is, 275 to
415 MPa. Therefore, the nano invar alloys according to the present
invention can be advantageously applied in the fields where there
is a demand for providing high strength. TABLE-US-00010 TABLE 10
Coefficients of thermal expansion of conventional invar alloy
Temperature range, Coefficient, .degree. C. .mu.m/mK As forged 17
to 100 1.66 17 to 250 3.11
[0042] TABLE-US-00011 TABLE 11 Coefficients of thermal expansion of
nano invar alloy (Fe-36 wt % Ni) according to the present invention
Temperature range, Coefficient, .degree. C. .mu.m/mK As forged 20
to 100 1.58 20 to 200 -1.78 20 to 300 -2.70 20 to 400 -3.82
[0043] Table 10 shows average coefficients of thermal expansion of
the conventional invar alloy depending on temperature ranges. As
shown in Table 10, the conventional invar alloy has an average
coefficient of thermal expansion of about 1.66 .mu.m/mK in a
temperature range of 17 to 100.degree. C., and the coefficient of
thermal expansion thereof increases as the temperature becomes
higher. On the other hand, the nano invar alloy (Fe-36 wt % Ni)
according to the present invention exhibits a coefficient of
thermal expansion of about 1.58 .mu.m/mK in a temperature range of
20 to 100.degree. C., the coefficient of thermal expansion of 0 in
a temperature range of 140 to 150.degree. C., and when the
temperature increases to 150.degree. C. or higher, the coefficient
of thermal expansion thereof becomes a negative value. When the
temperature is in a range of 20 to 200.degree. C., the average
coefficient of thermal expansion of the nano invar alloy according
to the present invention is -1.78, .mu.m/mK Such thermal expansion
behaviors are commonly exhibited when the Ni content of the nano
invar alloy according to the present invention is in a range of 33
to 38 wt %.
[0044] FIG. 2 shows a change in the coefficient of thermal
expansion of the nano invar alloy according to the present
invention depending on its composition ratio, confirming the facts
described hereinbefore. As shown in the drawing, in case that
percentages of the Ni content, by weight, are 33% and 38%, the
coefficients of thermal expansion for both cases are negative
values at a given temperature or higher. Therefore, since the nano
invar alloy according to the present invention has a negative
coefficient of thermal expansion, applications where such
properties are demanded may be newly possible applications of the
present invention.
[0045] FIG. 3 is a {111} pole figure of the texture after annealing
conventional invar alloy, FIG. 4A is a {100} pole figure of the
texture of the nano invar alloy according to the present invention,
and FIG. 4B is a {111} pole figure of the texture after annealing
the nano invar alloy according to the present invention.
[0046] As is apparent from the drawings, when the conventional
invar alloy is annealed, a growth texture of {001} <100> type
is dominantly indicated. On the contrary, in case of the nano invar
alloy according to the present invention, in a plated state, a
{100}//ND fiber type is dominantly indicated, and when annealed, a
growth of {111}//ND fiber texture type is indicated.
[0047] According to X-ray diffraction, the Fe--Ni alloy of the
present invention has a nanocrystalline structure having a grain
size of 5 to 15 nm. The results confirmed that the grain size of
the invar alloy composition having the Ni content of 36% is very
small to be in a range of 5 to 7 nm. Such a nanocrystalline
structure presumably accounts for high yield strength of the invar
alloy.
[0048] According to the present invention, since Fe--Ni alloys
having low thermal expansion properties is produced by a
single-step electroplating process, the production cost can be
greatly reduced. Particularly, since the Fe--Ni alloys according to
the present invention have a nanocrystalline structure, they
exhibit excellent mechanical properties, thereby creating a new
range in industrial uses.
* * * * *