U.S. patent application number 12/960034 was filed with the patent office on 2012-03-08 for preparation method of palladium alloy composite membrane for hydrogen separation.
This patent application is currently assigned to KOREA INSTITUTE OF ENERGY RESEARCH. Invention is credited to Heon Jung, Dong-Won Kim, Ho-Tae Lee, Jong-Soo Park, Wang-Lai Yoon.
Application Number | 20120055784 12/960034 |
Document ID | / |
Family ID | 36060282 |
Filed Date | 2012-03-08 |
United States Patent
Application |
20120055784 |
Kind Code |
A1 |
Park; Jong-Soo ; et
al. |
March 8, 2012 |
PREPARATION METHOD OF PALLADIUM ALLOY COMPOSITE MEMBRANE FOR
HYDROGEN SEPARATION
Abstract
Disclosed herein is a method of preparing a palladium alloy
composite membrane for hydrogen separation, including (a) providing
a first metal coating layer on a porous support using an
electroplating process; (b) providing a palladium coating layer on
the first metal coating layer using a dry plating process; and (c)
heat treating the palladium coating layer to form an alloy layer of
palladium and the first metal.
Inventors: |
Park; Jong-Soo; (Daejeon,
KR) ; Yoon; Wang-Lai; (Daejeon, KR) ; Lee;
Ho-Tae; (Daejeon, KR) ; Jung; Heon; (Daejeon,
KR) ; Kim; Dong-Won; (Daejeon, KR) |
Assignee: |
KOREA INSTITUTE OF ENERGY
RESEARCH
Daejeon
KR
|
Family ID: |
36060282 |
Appl. No.: |
12/960034 |
Filed: |
December 3, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11662432 |
Aug 30, 2007 |
7875154 |
|
|
12960034 |
|
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Current U.S.
Class: |
204/192.15 |
Current CPC
Class: |
B01D 71/022 20130101;
B01D 67/0069 20130101; B01D 67/0083 20130101; B01D 69/12 20130101;
B01D 67/009 20130101; B01D 67/0072 20130101; B01D 2323/40 20130101;
B01D 69/10 20130101; C01B 3/505 20130101 |
Class at
Publication: |
204/192.15 |
International
Class: |
C23C 14/34 20060101
C23C014/34; C23C 14/14 20060101 C23C014/14 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 15, 2004 |
KR |
10-2004-0073902 |
Claims
1. A method of preparing a palladium alloy composite membrane for
hydrogen separation, comprising: (a) forming a palladium coating
layer on a porous support using a dry sputtering deposition
process; (b) forming a metal coating layer on the palladium coating
layer using a dry sputtering deposition process; and (c) subjecting
the metal coating layer to a reflow process under a hydrogen
atmosphere to form an alloy layer.
2. The method according to claim 1, wherein the porous support is a
porous metal support or a porous ceramic support.
3. The method according to claim 2, wherein the porous metal
support is a porous nickel support.
4. The method according to claim 1, wherein the metal coating layer
is formed of copper.
5. The method according to claim 1, further comprising modifying a
surface of the porous support using a hydrogen plasma surface
treatment before the formation of the palladium coating layer of
the step (a).
Description
[0001] This is a divisional of application Ser. No. 11/662,432,
filed Aug. 30, 2007.
TECHNICAL FIELD
[0002] The present invention relates, generally, to a method of
preparing a palladium alloy composite membrane for hydrogen
separation, and, more particularly, to a method of preparing a
palladium alloy composite membrane for hydrogen separation, which
is advantageous because palladium is used in a small amount, and
thus a membrane for hydrogen separation having outstanding
selectivity to hydrogen gas and high durability can be prepared,
and, as well, the properties of the separation membrane can be
improved, regardless of the kind of support.
BACKGROUND ART
[0003] Generally, a separation membrane used for the preparation of
ultra highly pure hydrogen has low permeability. Hence, in order to
overcome such a problem, intensive and extensive research on
improvement of the selective permeability of the membrane by
applying a non-porous palladium membrane on a porous support is
presently being studied. The non-porous palladium membrane has high
hydrogen selectivity but has low permeability. Therefore, although
the selective hydrogen permeability of the separation membrane is
intended to increase by coating the surface of the porous support
with a thin palladium membrane, the separation membrane coated with
only palladium suffers because it may be deformed due to phase
change of the lattice structure while hydrogen gas is absorbed.
With the goal of preventing such deformation, a palladium alloy
separation membrane is mainly used at present.
[0004] A metal, which is alloyed with palladium, includes, for
example, silver, nickel, copper, ruthenium, molybdenum, etc. In
particular, a palladium-copper alloy membrane, which is prepared
using inexpensive copper, has resistance to hydrogen sulfide and
sulfur compound poisoning superior to other palladium alloy
membranes, and thus has been thoroughly studied in recent years. In
such cases, the alloy membrane is typically prepared by alloying a
copper plating layer and a plated palladium layer (or a sputtered
palladium layer) sequentially coated on a porous ceramic support or
a porous metal support. However, the palladium-copper alloy
membrane prepared using such a conventional method is
disadvantageous because it is not dense and has fine pores or
defects therein, thus having low hydrogen selectivity (FIG. 1).
Further, when the copper layer, serving as an alloy source, is
present as an intermediate layer between the support and the
palladium layer, it may be separated due to the thermal diffusion
and fluid reflow properties at a usage temperature of 500.degree.
C., therefore negatively affecting the adhesion. Consequently, the
palladium-copper alloy separation membrane breaks.
[0005] Turning now to FIG. 2, there is illustrated a
palladium-copper alloy membrane, which comprises a palladium-copper
alloy coating layer provided on a porous metal support by
sequentially forming a nickel plating layer as an underlayer of a
copper plating layer, a copper plating layer and a palladium
plating layer on the porous metal support and then heat treating
them. In addition, this drawing shows the result of heat treatment
for the alloy membrane at a usage temperature of 500.degree. C. for
100 hr.
[0006] From the surface microstructure of the separated upper
portion of the alloy membrane and the EDS result shown in FIG. 2,
it can be seen that the microstructure of membrane is not dense and
copper and palladium are present in the this portion.
[0007] FIG. 3 illustrates the surface microstructure of the
separated lower portion of the alloy membrane and the EDS result,
in which the microstructure of membrane is not dense and copper and
nickel are present in the this portion. Thereby, it appears that
the copper plating layer is separated through the thermal diffusion
of copper atoms and moved to the upper layer (palladium coating
layer) and the lower layer (support) of the copper plating
layer.
[0008] Recently, a palladium alloy composite separation membrane
has been developed using a porous metal support made of stainless
steel through an electroplating process. However, since the pore
size of the porous stainless steel support used is large and the
surface thereof is rough, a complicated pretreatment procedure is
required to apply the palladium alloy separation membrane. In the
case where the electroplating process is conducted on the porous
stainless steel support to form a palladium alloy coating layer,
the support may be corroded by hydrochloric acid acting as a main
component for activation of a plating process, and hydrogen
separation properties may decrease due to additive impurities in a
plating solution. In addition, the palladium metal is diffused into
the support at a usage temperature of 500.degree. C., thus
decreasing durability. As well, upon reforming of hydrogen gas,
hydrogen brittleness of a stainless steel substrate is caused by
the hydrogen absorption, and thus the substrate may break.
DISCLOSURE
Technical Problem
[0009] Accordingly, the present invention has been made to overcome
the above problems occurring in the related art, and an object of
the present invention is to provide a method of preparing a
palladium alloy composite membrane for hydrogen separation, which
is advantageous because a small amount of palladium is used, thus a
membrane for hydrogen separation having excellent hydrogen
selectivity and high durability can be prepared, and as well, the
properties of the separation membrane can be improved, regardless
of the kind of support.
Technical Solution
[0010] According to a first embodiment of the present invention for
achieving the above object, a method of preparing a palladium alloy
composite membrane for hydrogen separation is provided, comprising
(a) forming a palladium coating layer on a porous support; (b)
forming a metal coating layer on the palladium coating layer; and
(c) subjecting the metal coating layer to a reflow process to form
an alloy layer with a void free and dense film.
[0011] According to a second embodiment of the present invention, a
method of preparing a palladium alloy composite membrane for
hydrogen separation is provided, comprising (a) forming a first
metal coating layer on a porous support using an electroplating
process; (b) forming a palladium coating layer on the first metal
coating layer; (c) forming a second metal coating layer on the
palladium coating layer; and (d) subjecting the second metal
coating layer to a reflow process to form an alloy layer with a
void free and dense film.
[0012] In the method of the present invention, the porous support
is preferably a porous metal support or a porous ceramic
support.
[0013] In the method of the present invention, the porous support
is preferably a porous nickel support.
[0014] In the method according to the second embodiment of the
present invention, (a) preferably further comprises heat treating
the first metal coating layer formed using the electroplating
process to remove impurities.
[0015] In the method according to the second embodiment of the
present invention, the first metal coating layer is preferably
formed of at least one metal selected from the group consisting of
nickel, copper, and silver.
[0016] In the method according to the first embodiment of the
present invention, the first metal coating layer is formed of
nickel.
[0017] In the method according to the second embodiment of the
present invention, the second metal coating layer is formed of
copper.
Advantageous Effects
[0018] The present invention provides a method of preparing a
palladium alloy composite membrane for hydrogen separation.
According to the method of the present invention, even though
palladium is used in a small amount, the separation membrane having
excellent hydrogen selectivity and high durability can be prepared.
Further, the properties of the hydrogen separation membrane can be
improved, regardless of the kind of support.
DESCRIPTION OF DRAWINGS
[0019] FIG. 1 is a scanning electron micrograph showing the
microstructure of a palladium-copper alloy composite membrane
prepared using a conventional method;
[0020] FIG. 2 is a scanning electron micrograph showing the
microstructure of the separated upper portion of the alloy
composite membrane, in which a palladium-copper alloy coating layer
is provided on a porous metal support through heat treatment in
order to assay the durability of the membrane, and showing the
result of EDS analysis thereof;
[0021] FIG. 3 is a scanning electron micrograph showing the
microstructure of the separated lower portion of the alloy
composite membrane, and showing the result of EDS analysis
thereof;
[0022] FIG. 4 is a scanning electron micrograph showing the
microstructure of a palladium-copper alloy composite membrane
prepared through simple reflow heat treatment of a copper layer,
according to the present invention;
[0023] FIG. 5 shows the result of XRD analysis for the
palladium-copper alloy composite membrane of the present
invention;
[0024] FIG. 6 is a scanning electron micrograph showing the surface
microstructure of the alloy composite membrane, in which a nickel
coating layer, a sputtered palladium coating layer and a sputtered
copper coating layer are sequentially formed on a porous nickel
support and then heat treated at 600.degree. C. higher than an
actual usage temperature for 20 days in a nitrogen atmosphere, in
order to observe thermal stability;
[0025] FIG. 7 shows the result of crystal structure analysis of the
palladium-copper-nickel alloy composite membrane of the present
invention;
[0026] FIG. 8 is a scanning electron micrograph showing the cross
section of an alloy composite membrane sample of the present
invention;
[0027] FIG. 9 is an EDS line scan showing the cross section of the
alloy composite membrane sample of the present invention;
[0028] FIG. 10 is a scanning electron micrograph showing the
surface microstructure of a palladium-copper alloy composite
membrane, resulting from reflow heat treatment of a palladium
coating layer and a copper coating layer, each of which is formed
using an electroplating process, according to the present
invention;
[0029] FIG. 11 is a scanning electron micrograph showing the
surface microstructure of a palladium-copper alloy composite
membrane formed on a porous alumina support using a reflow process,
according to the present invention; and
[0030] FIG. 12 shows the hydrogen/nitrogen separation of the
palladium-copper alloy composite membrane formed on a porous nickel
support using a copper reflow process, upon use of a gas mixture
including hydrogen and nitrogen, according to the present
invention.
BEST MODE
[0031] Hereinafter, a detailed description will be given of a
method of preparing a palladium alloy composite membrane for
hydrogen separation, according to a first embodiment of the present
invention.
[0032] Based on the present invention, as the support for the
composite membrane, a porous metal support or a porous ceramic
support may be used. The porous support may be a planar type or a
tubular type. Compared to porous ceramic supports, the porous metal
support is advantageous because it entails a lower preparation
cost, higher thermal impact resistance and mechanical strength, and
higher processability and modularity, and is thus suitable for
application in highly pure hydrogen separation and purification
systems or catalyst reactors.
[0033] In particular, a porous nickel support has good chemical
affinity to palladium and nickel, which are main components of the
palladium alloy composite membrane. Further, compared to porous
stainless steel metal supports, the porous nickel support does not
generate hydrogen brittleness due to intrinsic properties thereof,
and has higher resistance to corrosion by hydrochloric acid. The
porous nickel support resulting from sintering of nickel powder has
an average pore size of sub-.mu.m or less than, and the pore
density thereof is uniform, thus no complicated pretreatment is
required when coated with a palladium alloy composite membrane. In
addition, the porous nickel support itself has hydrogen selectivity
of about 8.about.10 and permeability of 150 ml/cm.sup.2atmmin or
more and thereby has properties suitable for use in the metal
support of a palladium alloy composite membrane.
[0034] A palladium coating layer, which is applied on the porous
support, may be formed using either a wet electroplating process or
a dry sputtering deposition process. Preferably, an electroplating
process is adopted, so that the surface pores of the porous support
are completely filled and the surface flatness thereof is attained.
In this case, with the aim of improving adhesion between the
palladium coating layer and support, it is preferable that the
surface of the porous support be modified using plasma surface
treatment before the formation of the palladium coating layer.
Specifically, the plasma condition for surface modification may
vary with the process and is not particularly limited. For example,
in the case of using a porous nickel support, the plasma process
may be performed under conditions of RF 100 W, 50 mTorr, with an
amount of hydrogen of 40 sccm, and for 5 min.
[0035] When an electroplating process is used to form the palladium
coating layer, it is not particularly limited, and may preferably
be performed under conditions of a current density of 10
mA/dm.sup.2, a plating time of 20 min, and a plating bath
temperature of 40.degree. C. Alternatively, in the case of using a
dry sputtering deposition process, this process does not need a
particular limitation, and may preferably be carried out under
conditions of direct current (DC) power of 40 W, an amount of argon
gas of 25 sccm, a process pressure of 1.0.times.10.sup.-3 torr and
a substrate temperature of 400.degree. C.
[0036] Subsequently, a metal coating layer is formed on the
palladium coating layer. The kind of metal constituting the metal
coating layer is not particularly limited, and includes, for
example, silver, nickel, copper, ruthenium, or molybdenum. Of these
metals, copper is preferably used, because it is economically
advantageous and has high resistance to hydrogen sulfide and sulfur
compound poisoning for the alloy membrane with palladium.
[0037] The metal coating layer may be formed using either a wet
electroplating process or a dry sputtering deposition process. In
the case where the palladium coating layer is applied using an
electroplating process, the metal coating layer may be
electroplated through a continuous process, or be formed using
sputtering deposition. In addition, in the case where the palladium
coating layer is formed using a dry sputtering deposition process,
the metal coating layer may be deposited by sputtering through a
continuous process, or may be formed using electroplating.
[0038] The electroplating procedure of the metal coating layer by a
continuous process may be carried out under slightly different
conditions, depending on the kind of metal and an process ambience.
For example, in the case where copper is used as a metal component,
it may be coated using a copper cyanide plating solution under
conditions of a current density of 200 mA/dm.sup.2, a plating time
of 30 sec and a plating bath temperature of 40.degree. C.
[0039] In addition, when the metal coating layer is formed using
sputtering deposition by a continuous process, copper may be
deposited under conditions of DC power of 30 W, an amount of argon
gas of 20 sccm, a process pressure of 1.0.times.10.sup.-3 torr, and
a substrate temperature of 400.degree. C.
[0040] The two-layer metal membrane thus obtained is alloyed by a
subsequent reflow process, to form a palladium-metal alloy
composite membrane. The reflow process is preferably performed in
an in-situ process, and may be carried out through heat treatment
at 500.about.700.degree. C. in a vacuum of 1 mTorr in a hydrogen
atmosphere in a vacuum heating furnace. The reflow process results
in a uniform composite membrane having a dense alloy structure
without defects or fine pores.
[0041] In addition, a method of preparing a palladium alloy
composite membrane for hydrogen separation, according to a second
embodiment of the present invention, is specifically described
below.
[0042] The method according to the second embodiment is the same as
the preparation method of the first embodiment, with the exception
of further including a process of forming a metal underlayer (first
metal coating layer) on a porous support, before forming a
palladium coating layer, to fill the surface pores of the porous
support. Preferably, the metal underlayer is a nickel metal layer,
which may be formed using electroplating. The electroplating
process is preferable to a dry sputtering deposition process,
because it enables the surface pores of the porous support to be
completely filled and causes the surface to be flat. Further, in
order to improve adhesion before the formation of the nickel
plating layer, the surface modification of the porous support using
plasma is preferably performed. The advantage thereof is the same
as mentioned in the first embodiment.
[0043] Then, subsequent processes of forming a palladium coating
layer and a second metal coating layer (corresponding to the metal
coating layer in the first embodiment) are conducted in the same
manner as in the first embodiment, and the detailed description
thereof is omitted.
[0044] Before the formation of the palladium coating layer, the
surface of the first metal coating layer is preferably modified
using plasma. The plasma treatment conditions are the same as those
of the porous support.
[0045] Below, the present invention is explained based on an alloy
composite membrane for hydrogen separation using a nickel metal
layer as a first metal coating layer on a porous nickel support and
a copper metal layer as a second metal layer on the palladium
coating.
[0046] FIG. 4 is a scanning electron micrograph showing the
microstructure of the composite membrane according to the first
embodiment of the present invention, and FIG. 5 shows the result of
XRD analysis of the alloy composite membrane. From the surface
microstructure of FIG. 4 and the crystal analysis of FIG. 5, the
palladium-copper alloy membrane formed on the porous nickel support
can be confirmed to be a uniform separation membrane, which has a
dense structure, without defects or fine pores.
[0047] FIG. 6 shows the result of thermal stability of the alloy
composite membrane according to the second embodiment of the
present invention. To observe such thermal stability, a 3 .mu.m
thick nickel coating layer, a 4 .mu.m sputtered palladium coating
layer, and a 1 .mu.m sputtered copper coating layer are
sequentially formed on a porous nickel support and then heat
treated at 600.degree. C. higher than an actual usage temperature
for 20 days in a nitrogen atmosphere. Such heat treatment
corresponds to thermal effect similar to heat treatment at
500.degree. C. for 1 year or longer, assuming that the other
diffusion conditions thereof are the same.
[0048] FIG. 6 is a scanning electron micrograph showing the surface
microstructure of the membrane. As shown in the drawing, the alloy
layer is dense, without defects or fine pores, even though heat
treatment is performed. As is apparent from the XRD analysis of
FIG. 7, through continuous heat treatment, the chemical affinities
of palladium, copper and nickel for each other are good, and thus,
a stable ternary alloy membrane of palladium-copper-nickel is
formed and strongly adheres on the support.
[0049] FIG. 8 shows the result of diffusion in metals, in which
palladium is diffused into the support. As seen in an EDS
concentration distribution of FIG. 9 through heat treatment, the
palladium metal is diffused into the porous support, but a great
amount of palladium is still present in the coating layer, thus
forming a palladium-copper-nickel alloy separation membrane. As can
be shown in the cross section of the microstructure of FIG. 8, the
alloy membrane is dense, and also, adhesion between Pd alloy
membrane and support is excellent to the extent that the boundary
between the support and the alloy coating membrane is not observed
even using a scanning electron microscope.
[0050] From the results of FIGS. 8 and 9, the palladium metal is
less diffused into the porous metal support despite the use of the
porous metal support, and thus, a great amount of palladium is
present in the form of palladium-copper-nickel alloy composite
membrane. The structure of the alloy layer is still dense, and the
thermal stability of the palladium-copper-nickel alloy composite
membrane is excellent, whereby the durability thereof is considered
to be improved compared to conventional results.
[0051] FIG. 10 is a photograph showing the microstructure of a
palladium-copper alloy composite membrane, resulting from reflow
heat treatment of a palladium coating layer and a copper coating
layer, each of which is formed using electroplating. As shown in
this drawing, the alloy membrane is dense and has no fine
pores.
[0052] FIG. 11 is a photograph showing the microstructure of a
palladium-copper alloy composite membrane formed on a porous
alumina support using a reflow technique, in which the alloy
membrane is confirmed to have a very dense structure without fine
pores.
[0053] FIG. 12 shows the hydrogen/nitrogen selectivity varying with
the usage temperature of the palladium-copper alloy composite
membrane of the present invention, when using a gas mixture
including hydrogen and nitrogen under 2.2 psi pressure. As shown in
the drawing, as the temperature increases, the selectivity
increases and then reaches an infinite value at 500.degree. C.,
thus exhibiting excellent properties.
[0054] Compared to the hydrogen/nitrogen selectivity of a
palladium-copper alloy separation membrane prepared using a
conventional technique shown in Table 1 below, the palladium-copper
alloy composite membrane of the present invention is confirmed to
have higher hydrogen selectivity.
TABLE-US-00001 TABLE 1 Tem- Permea- Selec- Thick- .DELTA. P
perature bility (ml/ tivity ness (kPa) (K) cm.sup.2 min)
(H.sub.2/N.sub.2) (.mu.m) Gas Ex- 100 773 9 .infin. 3 .+-. 0.1 A
gas ample mixture including H.sub.2 and N.sub.2 1.sup.1) 689.5 723
6.45 14 27.6 .+-. 8.5 Each separated H.sub.2 and N.sub.2 gas
2.sup.1) 344.7 973 47 70 11.0 .+-. 1.0 '' 3.sup.1) 344.7 773 69.9
170 11.6 .+-. 1.0 '' 4.sup.1) 344.7 723 24 270 12.5 .+-. 1.5 ''
5.sup.1) 344.7 723 107 1400 12 .+-. 1.0 '' 6.sup.1) 344.7 723 88 47
1.5 .+-. 0.2 '' Note: .sup.1)Fernando Roa, Douglas Way, Robert L.
McCormick, Stephen N. Paglieri "Preparation and characterization of
Pd--Cu composite membranes for hydrogen separation" Chemical
Engineering Journals. 93 (2003)11-22.
MODE FOR INVENTION
[0055] A better understanding of the present invention may be
obtained in light of the following example which is set forth to
illustrate, but is not to be construed to limit the present
invention.
Example
[0056] A porous nickel support was surface treated using hydrogen
plasma. The surface treatment using hydrogen plasma was carried out
under conditions of RF power of 100 W, an amount of hydrogen of 40
sccm, a process pressure of 50 mTorr, and a period of time of 5
min. Subsequently, in order to fill the surface pores of the
support, a nickel electroplating process was performed on the
surface treated support at room temperature and a current density
of 1 A/dm.sup.2 for a plating time of 2 min using a nickel chloride
plating solution. After the nickel electroplating process, the
support was dried in a vacuum drying oven at 60.degree. C., and
then maintained at 200.degree. C. in a vacuum atmosphere of
10.sup.-3 torr for 1 hr to remove dust and impurities from the
inside of the support.
[0057] The support was further subjected to hydrogen plasma
treatment and then palladium electroplating using a palladium
chloride solution under conditions of a current density of 10
mA/dm.sup.2, a plating time of 20 min, and a plating bath
temperature of 40.degree. C. Thereafter, a copper electroplating
process was coated using a copper cyanide solution by a continuous
process, under conditions of a current density of 200 mA/dm.sup.2,
a plating time of sec, and a plating bath temperature of 40.degree.
C. After the formation of coating layers, reflow heat treatment was
carried out at 700.degree. C. in a vacuum of 1 mTorr in a hydrogen
atmosphere for 1 hr, thus alloying a copper layer and a palladium
layer.
[0058] On the other hand, in the case where a sputtering process
was employed as a dry preparation method, instead of the above wet
preparation method, all pretreatment processes and the formation
process of a nickel coating layer as a first coating layer were the
same as in the above wet method, and only the sputtering process
was carried out differently, as follows.
[0059] For the deposition of palladium, sputtering was carried out
under conditions of a DC power of 40 W, an amount of argon gas of
25 sccm, a process pressure of 1.0.times.10.sup.-3 torr, and a
substrate temperature of 400.degree. C., and copper sputtering was
continuously deposited under conditions of DC power of 30 W, an
amount of argon gas of 20 sccm, and a process pressure of
3.0.times.10.sup.-3 torr and a substrate temperature of 400.degree.
C. Subsequently, an in-situ reflow process was performed under heat
treatment conditions of a vacuum of 1 mTorr, and a reflow
temperature of 700.degree. C. for 1 hr in a hydrogen atmosphere of
a vacuum heating furnace, thus obtaining a palladium-copper-nickel
alloy composite separation membrane.
INDUSTRIAL APPLICABILITY
[0060] As described hereinbefore, the present invention provides a
method of preparing a palladium alloy composite membrane for
hydrogen separation. According to the method of the present
invention, even though palladium is used in a small amount, a
hydrogen separation membrane having outstanding hydrogen
selectivity and high durability can be prepared. Further, the
properties of the hydrogen separation membrane can be improved,
regardless of the kind of support.
[0061] Although the preferred embodiments of the present invention
have been disclosed for illustrative purposes, those skilled in the
art will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as disclosed in the accompanying
claims.
* * * * *