JP2005279535A - Hydrogen permeable membrane - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for suppressing degradation in hydrogen permeation characteristic of a hydrogen permeable membrane due to metal diffusion in the hydrogen permeable membrane. <P>SOLUTION: This hydrogen permeable membrane 234 is provided with a metal base layer L<SB>a</SB>containing group VA elements, two intermediate layers L<SB>b1</SB>, L<SB>b2</SB>which are formed on two surfaces of the metal base layer L<SB>a</SB>, respectively, and contains intermetallic compounds V2Zr and two cover layers L<SB>c1</SB>, L<SB>c2</SB>both containing Pd which are formed on the surfaces, of the sides not formed with the metal base layer, of the two intermediate layers, respectively. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hydrogen permeable membrane.

  The fuel cell system includes a fuel cell, a fuel gas supply unit that supplies a fuel gas containing hydrogen gas to the fuel cell, and an oxidizing gas supply unit that supplies an oxidizing gas containing oxygen gas to the fuel cell. The fuel gas supply method includes a method of directly supplying stored hydrogen gas and a method of manufacturing and supplying hydrogen gas from a hydrocarbon-based compound such as methanol. When the latter method is adopted, the fuel gas supply unit includes a reforming unit for reforming the hydrocarbon-based compound into hydrogen gas.

In the reforming part, other gas is usually generated together with hydrogen gas. For this reason, in the fuel gas supply unit, a hydrogen permeable membrane may be used to extract hydrogen gas from the mixed gas generated in the reforming unit. Patent Document 1 discloses a hydrogen permeable membrane in which a Pd (palladium) coating layer is formed on both sides of a V (vanadium) base layer. Patent Document 2 discloses a hydrogen permeable membrane in which a SiO ₂ intermediate layer is interposed between a V base layer and a Pd coating layer.

JP-A-11-276866 JP-A-7-185277

  However, when the hydrogen permeable membrane of Patent Document 1 is used at a high temperature of, for example, 400 ° C. or more, a Pd—V alloy layer is formed at the interface between V and Pd due to metal diffusion of V and Pd. Since the formed Pd—V alloy layer has extremely low hydrogen permeation performance, the hydrogen permeation performance of the hydrogen permeation membrane also deteriorates. The Pd-V alloy layer becomes thicker with time.

  On the other hand, the SiO2 intermediate layer of the hydrogen permeable membrane of Patent Document 2 is provided to suppress metal diffusion between V and Pd, but its suppression effect is low. Furthermore, the SiO2 intermediate layer has a low hydrogen permeation performance itself. Therefore, even if a ceramic such as SiO 2 is used as the intermediate layer, there is a problem that the hydrogen permeation performance of the hydrogen permeable membrane is lowered.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a technique for suppressing a decrease in hydrogen permeation characteristics of a hydrogen permeable membrane due to metal diffusion in the hydrogen permeable membrane.

The hydrogen permeable membrane of the present invention for solving at least a part of the above problems is
A hydrogen permeable membrane that selectively permeates hydrogen,
A metal base layer containing a Group VA element;
A coating layer containing Pd (palladium);
It is provided with the intermediate | middle layer containing the intermetallic compound formed between the said metal base layer and the said film layer.

  Here, the intermediate layer and the coating layer may be formed on both surfaces of the metal base layer, respectively.

  Since the intermetallic compound has a specific composition ratio and its crystal structure, solid solution due to metal diffusion hardly occurs between the metal base layer and the intermediate layer and between the intermediate layer and the coating layer. Therefore, according to the present invention, it is possible to suppress a decrease in hydrogen permeation characteristics due to diffusion between metals of the hydrogen permeable membrane.

  The “VA group” is also called “Group 5”. VA group elements include V (vanadium), Nb (niobium), and Ta (tantalum). The metal base layer may be a V alloy or the like.

  It is desirable that the intermetallic compound used here has a high hydrogen permeability. For example, V2Zr, LaNi5, FeTi, NiTi, CaNi, TiNi, LaCo, MgNi2, IrNi, MgIrNi, TiFe, TiMn, TiVMn, FeTi, Mg2Ni, ZrNi, ZrMn2, Zr3Rh, GeV3, HfV2, IrV3, SiV3 and the like can be mentioned.

In the hydrogen permeable membrane described above,
The intermetallic compound may be formed of an element whose solid solution amount with the group VA element and the Pd (palladium) is not more than a predetermined value, and is stable at least below the use temperature of the hydrogen permeable membrane. .

  According to this, since an intermetallic compound formed of an element that does not easily dissolve in the metal base layer or the coating layer is used for the intermediate layer, the metal diffusion of the hydrogen permeable membrane is less than that in the case where a simple intermetallic compound is used for the intermediate layer. The deterioration of the hydrogen permeation characteristic due to can be further suppressed.

  Elements that are difficult to dissolve in any of the VA group elements V and Pd include Be (beryllium), Er (erbium), Eu (europium), Ge (germanium), Ho (holmium), Nd (neodymium), Si (silicon) exists. Examples of intermetallic compounds that are formed of these elements and are stable at least below the use temperature of the hydrogen permeable membrane include Er5Ge3 (melting point 1950 ° C.), Er5Si3 (melting point 1948 ° C.), Eu3Ge (melting point 1215 ° C.), Ge3Ho5 (melting point 1950). ° C), Ge3Nd5 (melting point 1580 ° C), Ho5Si3 (melting point 1920 ° C), NdSi (melting point 1677 ° C), and the like.

The method of the present invention is a method for producing a hydrogen permeable membrane that selectively permeates hydrogen,
(A) preparing a metal base layer containing a VA group element;
(B) forming an intermediate layer containing an intermetallic compound on at least one of the two surfaces of the metal base layer;
(C) A step of forming a coating layer containing Pd (palladium) on the surface of the intermediate layer on which the metal base layer is not formed is provided.

  If this method is adopted, a hydrogen permeable membrane which is an apparatus of the present invention can be produced.

Here, the step (b)
(D) forming a layer of a substance that forms an intermetallic compound by reacting with the metal base layer at a predetermined temperature on at least one of the two surfaces of the metal base layer;
(E) The layer group formed in the step (d) may be heated to the predetermined temperature.

  By doing so, it is possible to manufacture the hydrogen permeable membrane which is the apparatus of the present invention without preparing an intermetallic compound used for the intermediate layer in advance. Examples of the substance include Zr (zirconium), Ti (titanium), and Mn (manganese). When Zr (zirconium) is used as the substance, an intermediate layer containing the intermetallic compound V2Zr is formed. On the other hand, when Ti (titanium) and Mn (manganese) are used as substances, an intermediate layer containing the intermetallic compound TiVMn is formed. Heating may be performed by a laser.

  The present invention can be realized in various aspects such as a fuel cell system using a hydrogen permeable membrane, a mobile device equipped with the fuel cell system, a hydrogen purifier using a hydrogen permeable membrane, and the like.

Hereinafter, embodiments of the present invention will be described in the following items.
A. Fuel cell system:
B. Hydrogen permeable membrane:
B-1. Hydrogen permeable membrane structure:
B-2. Manufacturing method of hydrogen permeable membrane:
B-3. effect:
C. Variation:

A. Fuel cell system:
Next, an embodiment of the present invention will be described. FIG. 1 is an explanatory diagram showing a schematic configuration of a fuel cell system according to an embodiment of the present invention. This fuel cell system includes a fuel cell 100, a fuel gas supply unit 200 that supplies a fuel gas containing hydrogen gas to the fuel cell 100, and an oxidizing gas supply unit 300 that supplies an oxidizing gas containing oxygen gas to the fuel cell 100. It is equipped with. The fuel cell 100 is a polymer electrolyte fuel cell that is relatively small and excellent in power generation efficiency.

  The fuel gas supply unit 200 (FIG. 1) generates a fuel gas containing hydrogen gas and supplies it to the fuel cell 100. The fuel gas supply unit 200 includes a raw material tank 212, a water tank 214, two evaporators 222 and 224, a fuel gas generation unit 230, a combustion unit 240, and a condenser 250. The raw material tank 212 stores methanol.

  The first evaporator 222 vaporizes the liquid mixture introduced from the raw material tank 212 and the water tank 214 and supplies a mixed gas of the raw material and water (hereinafter referred to as “raw material gas”) to the fuel gas generation unit 230. To do. The second evaporator 224 vaporizes the water introduced from the water tank 214 and supplies water vapor to the fuel gas generation unit 230.

  The fuel gas generation unit 230 includes a reforming unit 232, a hydrogen permeable membrane 234, and an extraction unit 236. As shown in the figure, the fuel gas generation unit 230 is integrated, and the hydrogen permeable membrane 234 is sandwiched between the reforming unit 232 and the extraction unit 236. A raw material gas is supplied from the first evaporator 222 to the reforming unit 232, and water vapor is supplied from the second evaporator 224 to the extraction unit 236.

  The reforming unit 232 carries a catalyst that causes the reforming reaction to proceed. As the catalyst, for example, a CuO—ZnO-based catalyst or a Cu—ZnO-based catalyst can be used. In the reforming unit 232, chemical reactions (reforming reactions) represented by the following formulas (1) and (2) proceed in sequence, and a mixed gas containing hydrogen gas is generated. And in the whole reforming part, the reforming reaction shown in Formula (3) proceeds.

CH ₃ OH → CO + 2H ₂ (1)
CO + H ₂ O → CO ₂ + H ₂ (2)
CH ₃ OH + H ₂ O → CO ₂ + 3H ₂ (3)

  The hydrogen permeable membrane 234 selectively transmits hydrogen gas from a mixed gas (that is, raw material gas, carbon monoxide gas, carbon dioxide gas, hydrogen gas, etc.) contained in the reforming unit 232, thereby generating hydrogen gas. Isolate. The hydrogen permeable membrane 234 will be described later.

  The extraction unit 236 promotes the permeation of hydrogen gas through the hydrogen permeable membrane 234 using the supplied water vapor. That is, the hydrogen gas generated in the reforming unit 232 passes through the hydrogen permeable membrane 234 according to the hydrogen partial pressure difference between the reforming unit 232 and the extraction unit 236. Therefore, in this embodiment, the hydrogen partial pressure of the extraction unit 236 is set lower than the hydrogen partial pressure of the reforming unit 232 by sequentially supplying water vapor to the extraction unit 236.

  In the present embodiment, the total pressure of the extraction unit 236 is set higher than the total pressure of the reforming unit 232. This is to prevent carbon monoxide gas from being mixed into the fuel gas obtained by the extraction unit 236. That is, if carbon monoxide gas is mixed in the fuel gas, the catalyst in the fuel cell 100 is poisoned by the carbon monoxide gas, and a stable electrochemical reaction is inhibited. However, if the total pressure of the extraction unit 236 and the reforming unit 232 is set as described above, the carbon monoxide gas inside the reforming unit 232 is extracted from the extraction unit 236 even when pinholes exist in the hydrogen permeable membrane 234. Can be prevented from leaking. Further, if water vapor leaks from the extraction unit 236 to the reforming unit 232 through the pinhole of the hydrogen permeable membrane 234, the leaked water vapor can be used for the reforming reaction (formula (3)). When no pinhole is present in the hydrogen permeable membrane 234, it is preferable to set the total pressure of the reforming unit 232 higher than the total pressure of the extraction unit 236 to improve the hydrogen gas separation efficiency.

  The impervious gas discharged from the reforming unit 232 (that is, the gas that has not passed through the hydrogen permeable membrane 234) is oxidized in the combustion unit 240 (FIG. 1). Specifically, carbon monoxide gas is oxidized to carbon dioxide gas, and hydrogen gas is oxidized to water vapor. Thereby, discharge | release to the air | atmosphere of the carbon monoxide gas contained in impermeable gas can be prevented.

  The fuel gas discharged from the extraction unit 236 is supplied to the condenser 250. The condenser 250 condenses and removes the water vapor contained in the fuel gas, and then supplies the fuel gas to the fuel cell 100. The condensed water obtained by the condenser 250 is returned to the water tank 214.

  The oxidizing gas supply unit 300 (FIG. 1) includes a blower 310 and supplies an oxidizing gas (air) containing oxygen gas to the fuel cell 100.

  The fuel cell 100 generates power using the fuel gas supplied from the fuel gas supply unit 200 and the oxidizing gas supplied from the oxidizing gas supply unit 300.

B. Hydrogen permeable membrane:
B-1. Hydrogen permeable membrane structure:
FIG. 2 is an explanatory view schematically showing a cross section of the hydrogen permeable membrane 234 shown in FIG. As shown in the figure, the hydrogen permeable membrane 234 has a five-layer structure. Specifically, the hydrogen permeable membrane includes one metal base layer La, two intermediate layers Lb1 and Lb2 formed on both surfaces of the metal base layer, and two coating layers Lc1 formed on the outer surface of each intermediate layer. , Lc2. The metal base layer, the intermediate layer, and the coating layer are formed with thicknesses of about 20 μm, about 0.1 μm, and about 0.3 μm, respectively.

  The metal base layer La contains a VA group element. As the VA group element, V (vanadium), Nb (niobium), or Ta (tantalum) can be used. The intermediate layers Lb1 and Lb2 contain an intermetallic compound. The coating layers Lc1 and Lc2 contain Pd (palladium).

  Hereinafter, a case where the metal base layer La is composed of V, the intermediate layers Lb1 and Lb2 are composed of the intermetallic compound V2Zr, and the coating layers Lc1 and Lc2 are composed of Pd will be described as an example.

  Hydrogen molecules are considered to permeate the hydrogen permeable membrane 234 in the process shown in FIG. That is, first, hydrogen molecules dissociate into two hydrogen atoms in the first Pd coating layer Lc1. The dissociated hydrogen atoms sequentially pass through the layers Lc1, Lb1, La, Lb2, and Lc2. The transmitted two hydrogen atoms recombine in the second Pd coating layer Lc2 to form hydrogen molecules.

  As can be seen from this explanation, Pd constituting the coating layers Lc1 and Lc2 has a catalytic function for promoting dissociation / recombination of hydrogen and a function for permeating hydrogen. Further, V2Zr constituting the intermediate layers Lb1 and Lb2 and V constituting the metal base layer La have a function of permeating hydrogen. The hydrogen permeation performance of V is considerably superior to that of Pd.

  By the way, as described above, when using a conventional hydrogen permeable membrane, that is, a hydrogen permeable membrane having a Pd coating layer formed on both sides of the V base layer, V and Pd gradually diffuse to each other, There is a problem that the hydrogen permeation performance of the hydrogen permeable membrane deteriorates with time. When a hydrogen permeable membrane having a ceramic intermediate layer formed between the V base layer and the Pd coating layer is used, diffusion between V and Pd can be reduced. There is a problem that transmission performance is lowered. This is because the ceramic intermediate layer transmits only hydrogen in a molecular state. That is, it is necessary to recombine once before hydrogen permeates the ceramic intermediate layer and dissociate again after permeation. Furthermore, when ceramic and metal are joined, there are problems that the production is relatively difficult and the hydrogen permeable membrane is easily cracked due to the difference in thermal expansion coefficient.

  Therefore, in this embodiment, as shown in FIG. 2, V2Zr intermediate layers Lb1 and Lb2 are interposed between the V base layer La and the Pd coating layers Lc1 and Lc2. Hereinafter, the reason why V2Zr which is an intermetallic compound is used for the intermediate layers Lb1 and Lb2 will be described.

  FIG. 3 is an explanatory diagram showing the results of the hydrogen permeation performance test. The graphs indicated by ● indicate the hydrogen permeability when Pd is coated on both sides of pure V by vacuum deposition and hydrogen permeation is performed at 250 ° C. to 400 ° C. for 2 to 3 hours. On the other hand, in the graph indicated by the asterisk, V2Zr intermetallic compound was arc-melted, further mechanically polished, and coated with Pd by vacuum deposition on both sides at 250 to 400 ° C. for 2 to 3 hours. The hydrogen permeability when hydrogen permeation is performed is shown. The test was performed on a pure V having a thickness of 1 mm and a V2Zr having a thickness of 3 mm. The hydrogen permeability in the graph is a thickness-corrected value and does not depend on the thickness. In both cases, the thickness of Pd is 100 nm.

  FIG. 3 shows that V2Zr exhibits a high hydrogen permeability equivalent to that of pure V. Further, it is generally known that intermetallic compounds have a slow interdiffusion due to heat of metal atoms because bonds between metal atoms are stronger than solid solution alloys. Therefore, if V2Zr is used as the intermediate layers Lb1 and Lb2, the hydrogen permeability of V2Zr itself is high, so that the hydrogen permeation performance of the entire hydrogen permeable membrane is prevented from being lowered, while V and Pd causing deterioration of the hydrogen permeation performance Interdiffusion can be suppressed, and the life of the hydrogen permeable membrane can be extended. Here, V2Zr has been described as an intermetallic compound, but the same can be said for an intermetallic compound having a high hydrogen permeability. For example, V2Zr, LaNi5, FeTi, NiTi, CaNi, TiNi, LaCo, MgNi2, IrNi, MgIrNi, TiFe, TiMn, TiVMn, FeTi, Mg2Ni, ZrNi, ZrMn2, Zr3Rh, GeV3, HfV2, IrV3, SiV3 and the like can be mentioned.

  In addition, the intermetallic compound used for intermediate | middle layer Lb1, Lb2 should be formed with the element whose solid solution possible amount with V base La and Pd coating layer Lc1, Lc2 based on a binary alloy phase diagram is below predetermined value Is more desirable. This is because, since it is difficult to dissolve in the V base La and the Pd coating layers Lc1 and Lc2, it is possible to further suppress a decrease in hydrogen permeation characteristics due to diffusion between metals of the hydrogen permeable membrane.

  FIG. 4 is an explanatory diagram simply showing a binary alloy phase diagram. The horizontal axis is the atomic ratio of Pd, and the vertical axis is the temperature. When the atomic ratio of Pd is 0%, the atomic ratio of Er is 100%. In the original binary alloy phase diagram, a detailed phase diagram is also shown in the hatched portion of FIG. 4, but it is omitted in FIG. 4 for simplicity. Α and β in FIG. 4 indicate the maximum solid solution amount at the operating temperature of the hydrogen permeable membrane. Er can be dissolved in α% with respect to Pd, and Pd can be dissolved in β% with respect to Er. It shows that there is. As described above, the solid solutionable amount of the element Er with the Pd coating layers Lc1 and Lc2 is equal to or less than a predetermined value. Both α and β in the binary alloy phase diagram of Er and Pd as shown in FIG. It is the following. The predetermined value is, for example, 20%.

  In other words, if a binary alloy phase diagram with V or Pd is examined for an arbitrary element, the solid solutionable amount with the V base La and the Pd coating layers Lc1 and Lc2 can be found. The intermetallic compound to be constructed can be selected. Elements that are difficult to dissolve in both V and Pd include Be (beryllium), Er (erbium), Eu (europium), Ge (germanium), Ho (holmium), Nd (neodymium), Si (silicon), and the like. Exists. Examples of intermetallic compounds that are formed of these elements and are stable at least below the use temperature of the hydrogen permeable membrane include Er5Ge3 (melting point 1950 ° C.), Er5Si3 (melting point 1948 ° C.), Eu3Ge (melting point 1215 ° C.), Ge3Ho5 (melting point 1950). ° C), Ge3Nd5 (melting point 1580 ° C), Ho5Si3 (melting point 1920 ° C), NdSi (melting point 1677 ° C), and the like.

B-2. Manufacturing method of hydrogen permeable membrane:
FIG. 5 is a flowchart showing a first manufacturing procedure of the hydrogen permeable membrane. In step S101, a base layer (foil) composed of V is prepared. The V base layer is etched with an alkaline solution to remove impurities such as an oxide film formed on the surface. In this way, it is possible to reduce the decrease in the hydrogen permeation performance of the hydrogen permeable membrane due to the remaining impurities. In step S102, two intermediate layers composed of V2Zr are formed on both sides of the V base layer. The V2Zr intermediate layer can be formed by, for example, electroless plating, electroplating, PVD, or CVD. In step S103, two coating layers made of Pd are formed on the outer surface of each V2Zr intermediate layer. The Pd coating layer can be formed by, for example, electroless plating, electroplating, PVD, or CVD. In this way, a hydrogen permeable membrane as shown in FIG. 2 is formed.

  FIG. 6 is a flowchart showing a second manufacturing procedure of the hydrogen permeable membrane. Note that steps S201 and S204 in FIG. 6 are the same as steps S101 and S103 in FIG. In step S202, two layers made of Zr are formed on both sides of the V base layer. The Zr layer can be formed by, for example, electroless plating, electroplating, PVD, or CVD. In step S203, heat treatment is performed with the Zr layer formed on both sides of the V base layer. The heat treatment is performed so that the Zr layer becomes a V2Zr layer by heating at a predetermined temperature for a predetermined time. A hydrogen permeable membrane as shown in FIG. 2 is formed by steps S201 to S204. In step S202, Ti (titanium) and Mn (manganese) may be used as materials constituting the layers formed on both sides of the V base layer. In that case, the heat treatment in step S203 is performed until the Ti and Mn layers become TiVMn layers.

  As described above, in the present embodiment, the case where V, V2Zr, and Pd are used has been described. However, instead of V, Nb or Ta having the same properties may be used. Also in this case, the above description can be applied in the same manner, and thus a detailed description is omitted.

  In this embodiment, the hydrogen permeable membrane has a five-layer structure of Pd-V2Zr-V-V2Zr-Pd, but may have a three-layer structure of Pd-V2Zr-V, for example. . That is, generally, the hydrogen permeable membrane is composed of a metal base layer containing a VA group element, a coating layer containing Pd, and an intermediate layer containing an intermetallic compound formed between the metal base layer and the coating layer. As long as it has.

B-3. effect:
As described above, according to the hydrogen permeable membrane of this embodiment, mutual diffusion between the metal base layer and the coating layer that causes deterioration of the hydrogen permeable performance while preventing the hydrogen permeable performance as a whole from being lowered. And the life of the hydrogen permeable membrane can be extended.

C. Variation:
In addition, this invention is not restricted to said embodiment, In the range which does not deviate from the summary, it can be implemented in a various aspect, For example, the following deformation | transformation is also possible.

(1) In the above embodiment (FIG. 1), the combustion section 240 for treating the carbon monoxide gas generated by the reforming reaction is provided on the downstream side of the reforming section 232. Instead, a shift unit and a CO oxidation unit may be provided. The shift unit generates hydrogen gas and carbon dioxide gas from carbon monoxide gas and water vapor. The CO oxidation unit oxidizes carbon monoxide gas that is not processed by the shift unit to generate carbon dioxide gas. When the shift part is provided in this way, a hydrogen permeable film may be provided in the shift part. If the hydrogen gas obtained in the shift unit is combined with the fuel gas discharged from the extraction unit 236 and supplied to the fuel cell 100, the utilization efficiency of the hydrogen gas can be improved.

(2) In the above embodiment, the fuel cell system includes the fuel gas supply unit 200 that generates fuel gas containing hydrogen gas using methanol, but instead of this, other alcohols, natural gas, You may make it provide the fuel gas supply part which produces | generates the fuel gas containing hydrogen gas using gasoline, ether, an aldehyde, etc. In general, various hydrocarbon compounds containing hydrogen atoms can be used as raw materials. Even in such a case, it is possible to improve the purity of hydrogen by using a hydrogen permeable membrane.

  In the above-described embodiment, the fuel cell system includes the fuel gas supply unit 200 that generates hydrogen gas by reforming methanol. Instead, the hydrogen gas is supplied from a hydrogen storage alloy or a hydrogen cylinder. You may make it provide the fuel gas supply part which obtains. Even in such a case, a hydrogen permeable membrane can be applied to improve the purity of hydrogen.

(3) In the above embodiment, the hydrogen permeable membrane 234 is a self-supporting membrane, but may be formed on a substrate. As a base material, porous members, such as an alumina and a sintered metal which can permeate | transmit hydrogen gas, can be used.

(4) In the above embodiment, the case where the hydrogen permeable membrane of the present invention is applied to a fuel cell system using a solid polymer type fuel cell has been described. However, the present invention is also applicable to a fuel cell system using another type of fuel cell. Is possible. It is also possible to apply the hydrogen permeable membrane to a hydrogen purifier.

It is explanatory drawing which shows schematic structure of the fuel cell system in embodiment of this invention. FIG. 2 is an explanatory view schematically showing a cross section of a hydrogen permeable membrane 234 shown in FIG. 1. It is explanatory drawing which shows the result of a hydrogen permeation performance test. It is explanatory drawing which showed the binary alloy phase diagram simply. It is a flowchart which shows the 1st preparation procedure of a hydrogen permeable film. It is a flowchart which shows the 2nd preparation procedure of a hydrogen permeable film.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Fuel cell 200 ... Fuel gas supply part 212 ... Raw material tank 214 ... Water tank 222,224 ... Evaporator 230 ... Fuel gas production | generation part 232 ... Reformation part 234 ... hydrogen permeable membrane 236 ... extraction part 240 ... combustion part 250 ... condenser 300 ... oxidizing gas supply part 310 ... blower La ... base layers Lb1, Lb2 ... intermediate Layer Lc1, Lc2 ... coating layer

Claims (5)

A hydrogen permeable membrane that selectively permeates hydrogen,
A metal base layer containing a Group VA element;
A coating layer containing Pd (palladium);
A hydrogen permeable membrane, comprising: an intermediate layer containing an intermetallic compound formed between the metal base layer and the coating layer. The hydrogen permeable membrane according to claim 1,
The intermediate layer and the coating layer are respectively formed on both sides of the metal base layer. The hydrogen permeable membrane according to claim 1,
The intermetallic compound is formed of an element having a solid solutionable amount with the VA group element and the Pd (palladium) having a predetermined value or less, and is stable at least below the use temperature of the hydrogen permeable film. A method for producing a hydrogen permeable membrane that selectively permeates hydrogen,
(A) preparing a metal base layer containing a VA group element;
(B) forming an intermediate layer containing an intermetallic compound on at least one of the two surfaces of the metal base layer;
(C) forming a coating layer containing Pd (palladium) on a surface on which the metal base layer is not formed, of the two surfaces of the intermediate layer. The manufacturing method according to claim 4,
The step (b)
(D) forming a layer of a substance that forms an intermetallic compound by reacting with the metal base layer at a predetermined temperature on at least one of the two surfaces of the metal base layer;
(E) A step of heating the layer group formed in the step (d) to the predetermined temperature.

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