JP2005013855A - Hydrogen separating body and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen separating body the hydrogen separating layer of which is hardly exfoliated and is hardly flawed and the airtightness of which is hardly deteriorated. <P>SOLUTION: This hydrogen separating body 1 is provided with a porous substrate 2 and the hydrogen separating layer 3 disposed on the substrate 2. The layer 3 is disposed on one surface 5 of the substrate 2 in such a state that a prescribed metallic layer 4 is interposed between them. The interposition of the layer 4 does not hinder the outflow of hydrogen from one surface side of the substrate 2 when a hydrogen-containing gas is made to flow in from the other surface side and improves the adhesive strength between the layer 3 and the substrate 2 much more than when the layer 3 is brought into direct contact with the substrate 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００６８】これら水素分離体（実施例１〜９、比較例１，２）についての、上記「５００℃−５０回熱処理後」の水素分離層からのヘリウムガスの漏洩量の測定結果を、チタン膜厚との関係として図３に示す。また、パラジウム膜厚が２．６μｍの実施例４及び比較例１と、パラジウム膜厚が５．０μｍの実施例５及び比較例２についての、上記、熱処理前、５００℃熱処理後、７００℃熱処理後及び５００℃−５０回熱処理後の、それぞれの熱サイクル条件における水素分離層からのヘリウムガスの漏洩量の測定結果を図４に示す。これら実施例及び比較例より、本発明の水素分離体は高温における熱処理後において、水素分離層の気密性が維持できることがわかる。また、チタン膜厚を０．０２μｍ〜０．５０μｍ程度とすることが特に望ましいことがわかる。
【００６９】
【発明の効果】上述したように、本発明の水素分離体によれば、水素分離層が、多孔質基体の一の表面に、多孔質基体との濡れ性が良好な所定の金属層を介在させた状態で配設され、その所定の金属層を介在させることにより、水素分離層と多孔質基体との間の接着性を、両者の直接的な接触による場合よりも向上させることができるため、高温状態と低温状態とを繰り返す熱サイクルを加えても、従来の水素分離体と比較して、水素分離層の剥離や欠陥が発生し難く、気密性や耐久性が大幅に向上される。
【００７０】また、本発明の水素分離体の製造方法によれば、多孔質基体の一の表面に所定の金属層を配設し、その所定の金属層の表面に水素分離層をメッキ処理により配設し、水素分離層と多孔質基体との間の接着性を、所定の金属層を介在させることにより、両者の直接的な接触による場合よりも向上させるため、高温状態と低温状態とを繰り返す熱サイクルを加えても、水素分離層の剥離や欠陥が発生し難く、気密性や耐久性が大幅に向上された水素分離体を得ることができる。
【図面の簡単な説明】
【図１】本発明の水素分離体の一の実施の形態を模式的に示す、水素分離層に垂直な平面で切断した断面図である。
【図２】本実施の形態の水素分離体の製造方法において水素分離体が得られる過程を模式的に示し、図２（ａ）は多孔質基体に所定の金属を配設したものを示す断面図であり、図２（ｂ）は得られた水素分離体を示す断面図である。
【図３】本発明の水素分離体及び従来技術に係る水素分離体における、「５００℃−５０回熱処理後」の、チタン膜厚と水素選択透過性金属層の気密性（ヘリウム漏洩量）との関係を示すグラフである。
【図４】本発明の水素分離体及び従来技術に係る水素分離体における、各熱サイクル条件と水素選択透過性金属層の気密性（ヘリウム漏洩量）との関係を示すグラフである。
【符号の説明】
１，１０…水素分離体、２，１２…多孔質基体、３，１３…水素分離層、４，１４…所定の金属層、５，１５…一の表面。[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrogen separator and a method for producing the same. The present invention relates to a body and a manufacturing method thereof.
[0002]
Conventionally, in order to selectively extract only hydrogen from a gas containing hydrogen such as steam reformed gas, a hydrogen separator having a hydrogen separation layer made of palladium or the like disposed on a ceramic porous substrate has been used. Has been. Since the hydrogen separator may be used to separate only hydrogen at a high temperature, the hydrogen separator is required to have high airtightness in an environment where high temperature or temperature rise and fall are repeated.
When a hydrogen separation layer such as palladium is disposed on a ceramic porous substrate to produce a hydrogen separator, palladium is disposed on the surface of the ceramic porous substrate by a method such as plating (for example, Patent Documents 1 to 3). However, in this case, the thermal expansion coefficients of palladium and the ceramic porous substrate are different, and furthermore, the wettability between the palladium and the ceramic porous substrate is not good, so when the temperature rise and fall is repeated and a thermal cycle is applied, There has been a problem that palladium is peeled off from the ceramic porous substrate, or defects are generated in palladium, resulting in a decrease in airtightness. In addition, after palladium is disposed on the ceramic porous substrate, silver or the like is disposed on the surface of the palladium, and then an alloy of palladium and silver is disposed on the ceramic porous substrate by heating to separate hydrogen. In the case of forming a layer, there is a problem that the alloy is more easily separated from the ceramic porous substrate.
[0004]
[Patent Document 1]
JP-A-3-146122
[Patent Document 2]
Japanese Patent No. 3213430
[Patent Document 3]
JP-A-62-273030
[0005]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and its object is to remove the hydrogen separation layer even if a thermal cycle is applied. It is an object of the present invention to provide a hydrogen separator and a method for producing the same, in which defects are hardly generated and hermeticity is hardly lowered.
[0006]
In order to achieve the above object, the present invention provides the following hydrogen separator and method for producing the same.
[0007]
[1] A porous substrate having a large number of pores communicating from one surface to another surface, and a gas containing hydrogen that is disposed on the porous substrate and flows from the one or other surface side A hydrogen separator that selectively allows only hydrogen to permeate and flow out from the other or one surface side, wherein the hydrogen separator is the one of the porous substrates. The hydrogen separation layer is disposed with a predetermined metal layer interposed on the surface thereof, and without interfering the outflow of hydrogen from the other or one surface side by interposing the predetermined metal layer. The hydrogen separator is characterized in that the adhesion between the porous substrate and the porous substrate is improved as compared with the case of direct contact between the two.
[0008]
[2] The hydrogen separator according to [1], wherein the predetermined metal layer is a metal layer made of titanium (Ti).
[0009]
[3] The hydrogen separator according to [1] or [2], wherein the porous substrate has ceramic as a main component.
[0010]
[4] The hydrogen separator according to any one of [1] to [3], wherein the hydrogen separation layer is made of a hydrogen selective permeable metal.
[0011]
[5] The hydrogen separator according to [4], wherein the hydrogen selective permeable metal is palladium or an alloy containing palladium.
[0012]
[6] The hydrogen separator according to any one of [1] to [5], wherein the hydrogen separation layer has a thickness of 1 to 5 μm.
[0013]
[7] The hydrogen separator according to any one of [1] to [6], wherein the predetermined metal layer is formed by a vacuum deposition method.
[0014]
[8] Hydrogen among a gas including a porous substrate having a large number of pores communicating from one surface to another surface, and hydrogen flowing from the one surface side disposed on the porous substrate. And a hydrogen separation layer capable of selectively permeating and flowing out from the other surface side, wherein a predetermined metal layer is formed on the one surface of the porous substrate. The hydrogen separation layer is disposed by plating on the surface of the predetermined metal layer, and the adhesion between the hydrogen separation layer and the porous substrate is interposed between the predetermined metal layer. Thus, the method for producing a hydrogen separator can be improved as compared with the case of direct contact between the two without impeding the outflow of hydrogen from the other surface side.
[0015]
[9] The method for producing a hydrogen separator according to [8], wherein the predetermined metal layer is a metal layer made of titanium (Ti).
[0016]
[10] The method for producing a hydrogen separator according to [8] or [9], wherein the porous substrate contains ceramic as a main component.
[0017]
[11] The method for producing a hydrogen separator according to any one of [8] to [10], wherein the hydrogen separation layer is made of a hydrogen selective permeable metal.
[0018]
[12] The method for producing a hydrogen separator according to [11], wherein the hydrogen selective permeable metal is palladium or an alloy containing palladium.
[0019]
[13] The method for producing a hydrogen separator according to any one of [8] to [12], wherein the hydrogen separation layer has a thickness of 1 to 5 μm.
[0020]
[14] The method for producing a hydrogen separator according to any one of [8] to [13], wherein the predetermined metal layer is disposed by a vacuum deposition method.
As described above, according to the hydrogen separator of the present invention, the hydrogen separation layer is disposed in a state where the predetermined metal layer is interposed on the surface of the porous substrate. By interposing, the hydrogen separation layer and the porous layer are not disturbed without preventing hydrogen from flowing out from the other surface side or the one surface side when the gas containing hydrogen flows from the one surface side or the other surface side. Since the adhesion between the porous substrates is improved compared to the case of direct contact between the two, the separation of the hydrogen separation layer and defects are less likely to occur even when a thermal cycle is applied, and the hermeticity is unlikely to decrease. Become.
According to the method for producing a hydrogen separator of the present invention, a predetermined metal layer is disposed on one surface of the porous substrate, and a hydrogen separation layer is disposed on the surface of the predetermined metal layer by plating. In addition, by interposing a predetermined metal layer between the hydrogen separation layer and the porous substrate, when a gas containing hydrogen flows from one surface side or the other surface side, the hydrogen is In order not to prevent the flow from one surface side or the other surface side, but to improve compared to the case of direct contact between the two, even if a thermal cycle is applied, peeling and defects of the hydrogen separation layer are unlikely to occur. It is possible to obtain a hydrogen separator that is less likely to deteriorate in properties.
[0023]
DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments and does not depart from the spirit of the present invention. It should be understood that design changes, improvements, and the like can be made as appropriate based on ordinary knowledge of those skilled in the art.
FIG. 1 is a cross-sectional view taken along a plane perpendicular to the hydrogen separation layer, schematically showing one embodiment of the hydrogen separator of the present invention.
As shown in FIG. 1, the hydrogen separator 1 of the present embodiment includes a porous substrate 2 having a large number of pores communicating from one surface 5 to another surface (not shown), Of the gas containing hydrogen that is disposed on the porous substrate 2 and flows from one surface 5 side or another surface (not shown), only hydrogen is selectively permeated to the other surface (not shown). ) Side or hydrogen separation layer 3 capable of flowing out from one surface 5 side, wherein the hydrogen separation layer 3 is a predetermined metal layer on one surface 5 of the porous substrate 2. 4 is arranged in a state of interposing, and by interposing a predetermined metal layer 4, hydrogen separation without interfering with the outflow from the other surface (not shown) side of hydrogen or one surface 5 side. The adhesion between the layer 3 and the porous substrate 2 is improved compared to the case of direct contact between them. The features. When hydrogen is separated from a gas containing hydrogen by the hydrogen separator 1, the gas containing hydrogen may be flowed in from one surface 5 side and flowed out from the other surface (not shown) side. It is possible to flow in from the surface (not shown) side of the liquid and to flow out from the surface 5 side.
As described above, the hydrogen separation layer 3 is disposed in a state where the predetermined metal layer 4 is interposed on one surface 5 of the porous substrate 2, and the hydrogen separation layer 3, the porous substrate 2, Since the adhesion between the two is improved compared to the case of direct contact between the two, the hydrogen separation layer 3 is less prone to exfoliation and defects even when a thermal cycle is applied, and the hydrogen separation is less likely to reduce the hermeticity. The body 1 can be obtained.
The porous substrate 2 constituting the hydrogen separator 1 of this embodiment is preferably a porous body mainly composed of ceramic. By using ceramic as a main component, the hydrogen separator 1 having excellent heat resistance, corrosion resistance, and the like and high mechanical strength can be obtained. The ceramic is not particularly limited, and any ceramic generally used as a hydrogen separator can be employed. Examples thereof include alumina, silica, silica-alumina, mullite, cordierite, zirconia and the like. As components other than ceramics, a small amount of components inevitably contained or components that are usually added may be contained. The porous substrate 2 has a large number of fine pores which are three-dimensionally continuous. The pore diameter of the pores is preferably 0.003 to 2 μm, preferably 0.1 to 1 μm. More preferably. When the pore diameter is less than 0.003 μm, the resistance when the gas passes may increase. On the other hand, when the pore diameter exceeds 2 μm, when the hydrogen separation layer 3 is disposed by chemical plating when the hydrogen separator 1 of the present embodiment is manufactured, the pores are blocked by the hydrogen selective permeable metal. This is not preferable because it becomes difficult and airtightness may be lowered.
The pores of the porous substrate 2 preferably have the same pore diameter. As a result, when the hydrogen separation layer 3 is disposed by the above chemical plating, it is easy to allow the plating solution to uniformly enter the pores without leaking, and pores that are not filled with the hydrogen selective permeable metal are generated, resulting in a decrease in airtightness. Can avoid problems.
The predetermined metal layer 4 has good wettability with the porous substrate 2 and good adhesion. Thereby, even if a thermal cycle is applied to the obtained hydrogen separator 1, it is possible to suppress the occurrence of peeling from the connection portion between the porous substrate 2 and the predetermined metal layer 4. When the porous substrate 2 is mainly composed of ceramic, the metal constituting the predetermined metal layer 4 is preferably titanium. The hydrogen separation layer 3 is preferably made of a hydrogen selective permeable metal. By comprising in this way, since the wettability of titanium and a ceramic is good, the adhesiveness between titanium and a ceramic becomes favorable. And since both titanium and a hydrogen selective permeable metal are metals, the adhesiveness is favorable. That is, by adopting a structure in which titanium is interposed between the ceramic and the hydrogen selective permeable metal, the adhesiveness between the hydrogen separation layer 3 and the porous substrate 2 can be more improved than in the case of direct contact between the two. Will be improved. Therefore, by applying a heat cycle of heating and cooling to the hydrogen separator 1, even if the hydrogen separation layer 3 and the porous substrate 2 repeatedly expand and contract, the hydrogen separation layer 3 is less likely to be peeled off or defective, and is airtight. It becomes difficult to decrease the nature.
The predetermined metal layer 4 is a metal layer containing a metal (active metal) that has good wettability with the porous substrate 2 and can be appropriately determined according to the material of the porous substrate 2. it can. As the active metal, for example, when the porous substrate 2 is made of ceramic, titanium is preferable as described above, but besides titanium, zirconium (Zr), niobium (Nb), tantalum (Ta), vanadium. (V) etc. can be mentioned.
The thickness of the predetermined metal layer 4 is preferably 0.01 to 1 μm. If it is thinner than 0.01 μm, the effect of improving the adhesion between the hydrogen separation layer 3 and the porous substrate 2 may be reduced. If it is thicker than 1 μm, the pores of the porous substrate 2 may be blocked. . The predetermined metal layer 4 needs to cover one surface 5 of the porous substrate 2 so as not to block the pores. As a result, hydrogen that has permeated through the hydrogen separation layer 3 can pass through the pores and flow out from the other surface (not shown) side of the porous substrate 2. Furthermore, since the active metal forms a hydride and destroys a predetermined metal layer, if it is thicker than 1 μm, the hydrogen separation layer may be destroyed.
The thickness of the hydrogen separation layer 3 is preferably 1 to 5 μm. If the thickness is less than 1 μm, defects may easily occur in the hydrogen separation layer 3. If the thickness is more than 5 μm, the separation efficiency of hydrogen separation by the hydrogen separation layer 3 may be reduced.
The hydrogen selective permeable metal constituting the hydrogen separation layer 3 is not particularly limited as long as it can selectively permeate hydrogen, and examples thereof include palladium or an alloy containing palladium. Among these, palladium or an alloy containing palladium is preferable. Palladium can selectively permeate only hydrogen efficiently. As the alloy containing palladium, an alloy of palladium and silver is preferable. By alloying palladium and silver, hydrogen embrittlement of palladium is prevented, and the separation efficiency of hydrogen at high temperatures is improved.
Next, an embodiment of the method for producing a hydrogen separator according to the present invention will be described in detail with reference to the drawings.
FIGS. 2 (a) and 2 (b) schematically show the process of obtaining a hydrogen separator in the method for producing a hydrogen separator of the present embodiment, and FIG. 2 (a) shows a porous substrate. FIG. 2B is a cross-sectional view showing a hydrogen separator obtained by arranging a predetermined metal in FIG.
In the method for producing a hydrogen separator according to this embodiment, first, as shown in FIG. 2A, a large number of pores communicating from one surface 15 to another surface (not shown) are formed. A predetermined metal layer 14 is disposed on one surface 15 of the porous substrate 12 having the porous substrate 12. Then, as shown in FIG. 2B, the hydrogen separator 10 is obtained by disposing the hydrogen separation layer 13 on the surface of the predetermined metal layer 14 by plating. When hydrogen is separated from a gas containing hydrogen by the hydrogen separator 10, the gas containing hydrogen may be introduced from one surface 15 side or from the other surface (not shown) side. Also good.
The porous substrate 12 is preferably a porous body mainly composed of ceramic. By using ceramic as a main component, the hydrogen separator 10 having excellent heat resistance, corrosion resistance and the like and high mechanical strength can be obtained. The ceramic is not particularly limited, and any ceramic generally used as a hydrogen separator can be employed. Examples thereof include alumina, silica, silica-alumina, mullite, cordierite, zirconia and the like. As components other than ceramics, a small amount of components inevitably contained or components that are usually added may be contained. The porous substrate 12 has a large number of fine pores that are three-dimensionally continuous. The pore diameter of the pores is preferably 0.003 to 2 μm, preferably 0.1 to 1 μm. More preferably. When the pore diameter is less than 0.003 μm, the resistance when the gas passes may increase. On the other hand, when the pore diameter exceeds 2 μm, when the hydrogen separation layer 13 is disposed by chemical plating when the hydrogen separator 10 is manufactured by the method of manufacturing a hydrogen separator of the present embodiment, hydrogen selective permeability is obtained. Since it becomes difficult to block pores by metal and airtightness may be lowered, it is not preferable.
Further, it is preferable that the pores of the porous substrate 12 have the same pore diameter. As a result, when the hydrogen separation layer 13 is disposed by the above chemical plating, it is easy to allow the plating solution to uniformly enter the pores without leaking, and pores that are not filled with the hydrogen selective permeable metal are generated, and the airtightness is lowered. Can avoid problems.
The predetermined metal layer 14 has good wettability with the porous substrate 12 and good adhesion. For example, when the porous substrate 12 is ceramic, the predetermined metal layer 14 is preferably made of titanium. Thereby, even if a thermal cycle is applied to the obtained hydrogen separator, it is possible to suppress the occurrence of peeling from the connection portion between the ceramic and titanium.
The method of disposing titanium on the ceramic porous substrate 12 is not particularly limited, but it is preferable to form a titanium film on one surface 15 of the porous substrate 12 by vacuum deposition. . By forming the titanium film by the vacuum deposition method, a film having a desired thickness can be uniformly disposed on the entire surface 15.
When titanium is disposed on the porous substrate 12 by vacuum vapor deposition, the cleaned porous substrate is disposed in the upper part of the vacuum container, the inside is evacuated, and the titanium metal is heated and melted in the crucible at the lower part of the container. And it can arrange | position by applying the vapor | steam to a porous base material.
In addition to the vacuum deposition method, a predetermined metal layer 14 may be disposed on the porous substrate 12 by sputtering, plasma CVD, or the like.
The thickness of the predetermined metal layer 14 is preferably 0.01 to 1 μm. If it is thinner than 0.01 μm, when the hydrogen separation layer 13 (see FIG. 2B) is provided, the effect of improving the adhesiveness with the porous substrate 12 may be reduced, and it is thicker than 1 μm. In some cases, the pores of the porous substrate 12 are blocked. The predetermined metal layer 14 needs to cover one surface 15 of the porous substrate 12 so as not to block the pores. Thereby, for example, when a gas containing hydrogen is introduced from the one surface 15 side, the hydrogen that has permeated through the hydrogen separation layer 13 (see FIG. 2B) passes through the pores and becomes porous substrate 12. It becomes possible to flow out from the other surface (not shown) side. Furthermore, since the active metal forms a hydride and destroys a predetermined metal layer, if it is thicker than 1 μm, the hydrogen separation layer may be destroyed.
The metal constituting the predetermined metal layer 14 is not particularly limited, and a metal that has good wettability with the porous substrate 12 is appropriately determined according to the material of the porous substrate 12. be able to. For example, when the porous substrate 12 is made of ceramic, titanium is preferable as described above, but other than titanium, zirconium (Zr), niobium (Nb), tantalum (Ta), vanadium (V), and the like can be given. be able to.
As described above, after the predetermined metal layer 14 is disposed on the one surface 15 of the porous substrate 12, the hydrogen separation layer 13 is disposed on the surface of the predetermined metal layer 14 by plating. . By disposing the hydrogen separation layer 13, when a gas containing hydrogen flows from one surface 15 side of the porous substrate 12, only hydrogen is selectively permeated so that the other surface of the porous substrate 12 (see FIG. (Not shown) can flow out from the side. Further, when a gas containing hydrogen flows from the other surface (not shown) side, only hydrogen can be selectively permeated by the hydrogen separation layer 13 to flow out from the one surface 15 side of the porous substrate 12. it can.
The hydrogen separation layer 13 is preferably made of a hydrogen selective permeable metal. The hydrogen selective permeable metal is not particularly limited as long as it can selectively permeate hydrogen, and palladium, an alloy containing palladium, or the like can be used. Among these, palladium or an alloy containing palladium is preferable. Palladium can selectively permeate only hydrogen efficiently. As the alloy containing palladium, an alloy of palladium and silver is preferable. By alloying palladium and silver, hydrogen embrittlement of palladium is prevented, and the separation efficiency of hydrogen at high temperatures is improved.
When the hydrogen separation layer 13 is disposed on the surface of the predetermined metal layer 14 by plating, for example, palladium is preferably disposed on the surface of the predetermined metal layer 14 by chemical plating.
When palladium is disposed on the surface of the predetermined metal layer 14 by chemical plating, first, the porous substrate 12 on which the predetermined metal layer 14 is disposed is immersed in a solution containing activated metal. A solution containing an activated metal is attached to the surface side of the metal layer 14 and washed with water. As the activated metal, a compound containing a palladium divalent ion can be suitably used. As a method of attaching the activated metal to the predetermined metal layer 14 side of the porous substrate 12, in the case of disposing palladium as the hydrogen selective permeable metal, the porous substrate 12 is treated with an aqueous hydrochloric acid solution of palladium chloride, and chloride. It is preferable to alternately immerse in an aqueous hydrochloric acid solution of tin.
After depositing the activated metal on the predetermined metal layer 14 side of the porous substrate 12, the predetermined metal layer 14 side of the porous substrate 12 is bonded with a hydrogen selective permeable metal (palladium) and a reducing agent. Immerse in the plating solution. Thereby, palladium is deposited with the activated metal as a nucleus, and a hydrogen separation layer 13 made of palladium is formed. Examples of the reducing agent include hydrazine, dimethylamine borane, sodium phosphinate, sodium phosphonate and the like.
The hydrogen separator 10 produced in this way shown in FIG. 2B is provided with a predetermined metal layer 14 made of titanium on one surface 15 of a ceramic porous substrate 12. In addition, since the hydrogen separation layer 13 made of palladium is disposed on the surface of the predetermined metal layer 14, the adhesion between the hydrogen separation layer 13 and the porous substrate 12 is improved by direct contact between the two. Thus, even if a heat cycle is applied, the hydrogen separation layer 13 is less prone to exfoliation and defects, and the hermeticity is not easily lowered.
In the method for manufacturing a hydrogen separator according to this embodiment, the thickness of the hydrogen separation layer 13 is preferably 1 to 5 μm. If the thickness is less than 1 μm, defects may easily occur in the hydrogen separation layer 13. If the thickness is more than 5 μm, the separation efficiency of hydrogen separation by the hydrogen separation layer 13 may be reduced.
In the method of manufacturing a hydrogen separator according to the present embodiment, when the hydrogen selective permeable metal constituting the hydrogen separation layer 13 is an alloy of palladium and silver, the palladium membrane is placed on the surface of the predetermined metal 14. After disposing by chemical plating, silver is further plated on the surface of the palladium film. Subsequently, it is preferable that palladium and silver are mutually diffused by heating to form an alloy of palladium and silver. When silver is plated on the surface of the palladium film, electroplating is preferably performed using the palladium film as an electrode. At this time, the mass ratio of palladium to silver (palladium: silver) is preferably 90:10 to 70:30.
[0053]
EXAMPLES The present invention will be described in detail below by way of examples, but the present invention is not limited to these examples.
[0054]
(Example 1)
A plate-shaped asymmetric inorganic porous material (manufactured by α-alumina, manufactured by NGK Adrec Co., Ltd.) was used as the porous substrate. This has a diameter of 30 mm and a thickness of 3.5 mm, and the average pore diameter in the vicinity of the surface is 0.1 μm.
A predetermined layer made of titanium having a thickness (titanium film thickness) of 0.01 μm is formed on one surface of the ceramic porous substrate as a metal layer having good wettability with the ceramic porous substrate. The metal layer is vacuum evaporated and the nitrogen gas pressure is 2 × 10 ^-4 Pa was used, and the substrate temperature was room temperature. A palladium film having a thickness of 2.0 μm is formed as a hydrogen separation layer by an electroless plating method on the surface of a predetermined metal layer made of titanium disposed on one surface of the ceramic porous substrate, A separated body was obtained (Example 1).
A method for forming a palladium membrane (hydrogen separation layer) on the surface of the predetermined metal layer by electroless plating will be described below.
First, the porous body on which titanium was disposed was washed with water. Next, as a degreasing treatment, a solution containing 10% by volume of OPC370 manufactured by Okuno Pharmaceutical Co., Ltd. was maintained at 70 ° C., immersed for 5 minutes, and then washed with water.
Next, the porous substrate on which titanium was disposed was activated. The porous substrate was immersed in a solution containing 1% by volume of OPC pre-dip manufactured by Okuno Pharmaceutical Co., Ltd. for 2 minutes. Next, a solution containing 5% by volume of each of Inducer A and Inducer C manufactured by Okuno Pharmaceutical Co., Ltd. was kept at 50 ° C., immersed for 5 minutes, and then washed with water. Next, it was immersed for 5 minutes in a solution containing 15% by volume of Crister MU manufactured by Okuno Pharmaceutical Co., Ltd. Next, after immersing in a solution containing 3% by volume of Crister MU manufactured by Okuno Pharmaceutical Co., Ltd. for 1 minute, it was washed with water to obtain an activation-treated substrate with palladium nuclei attached as an activation metal.
Next, the activation substrate was subjected to a chemical plating treatment to form a hydrogen separation layer using palladium as a hydrogen selective permeable metal. In 1 L (liter) of water from which ions have been removed, [Pd (NH ₃ ) ₄ ] Cl ₂ ・ H ₂ O (5.4 g), 2Na · EDTA (67.2 g), ammonia water having an ammonia concentration of 28 mass% (651.3 mL) and H ₂ NNH ₂ ・ H ₂ An aqueous solution to which O (0.64 mL) was added was prepared. The temperature of the aqueous solution was controlled at 50 ° C., and the outer surface of the activation-treated substrate was immersed in the aqueous solution. The immersion time was 15 minutes, whereby a hydrogen separation layer made of palladium was formed on the surface of titanium (predetermined metal layer) disposed on the surface, and a porous substrate (hydrogen separator) was obtained.
[0060]
(Examples 2-9)
In Example 1, the thickness of the predetermined metal layer made of titanium (titanium film thickness) is 0.025 μm, 0.05 μm, 0.05 μm, 0.05 μm, 0.10 μm, 0.15 μm, 0.50 μm, 1 By sequentially changing to 0.000 μm and sequentially changing the palladium film thickness to 2.1 μm, 1.8 μm, 2.6 μm, 5.0 μm, 2.1 μm, 1.9 μm, 2.0 μm, and 1.9 μm, The hydrogen separators of Examples 2 to 9 were obtained. A hydrogen separator was produced in the same manner as in Example 1 except for the above conditions.
[0061]
(Comparative Example 1)
In Example 1, a palladium film having a thickness of 2.6 μm was directly formed on one surface of the porous substrate without forming a predetermined metal layer made of titanium on one surface of the porous substrate. A hydrogen separator was prepared in the same manner as in Example 1.
[0062]
(Comparative Example 2)
In Comparative Example 1, a hydrogen separator was produced in the same manner as in Comparative Example 1, except that the thickness of the palladium film was 5.0 μm.
The thicknesses of the titanium film and the palladium film constituting the predetermined metal layer were measured by measuring the intensity of fluorescent X-rays.
With respect to the hydrogen separators (Examples 1 to 9, Comparative Examples 1 and 2) obtained by the above method, the amount of helium gas leaked from the hydrogen separation layer made of a palladium membrane was measured. The amount of leakage of this helium gas was measured before the thermal cycle (heat treatment) and after the thermal cycle (heat treatment).
The amount of helium gas leaked from the hydrogen separation layer (before heat treatment) was determined by introducing helium gas into the palladium membrane side of one surface of the hydrogen separator and holding it at a pressure of 250 kPa. It was obtained by measuring the amount of gas leaking to the surface side.
The amount of leakage of helium gas from the hydrogen separation layer after the thermal cycle was applied to the hydrogen separator was as follows. After heat treatment for 1 hour at an argon gas pressure of 100 kPa and 700 ° C. (after heat treatment at 700 ° C.) Further, after heat treatment for 1 hour at a hydrogen gas pressure of 100 kPa and 500 ° C. (after heat treatment at 500 ° C.), the temperature was further raised from room temperature to 500 ° C. at a nitrogen gas pressure of 100 kPa, and the hydrogen gas pressure of 100 kPa and 500 ° C. The heat treatment was performed for 1 hour and the temperature was lowered to room temperature at a nitrogen gas pressure of 100 kPa as one cycle. After this was performed 50 times (after 500 ° C.-50 times heat treatment), each was measured. The results are shown in Table 1 together with the measurement results when the thermal cycle is not applied to the hydrogen separator (before heat treatment).
[0067]
[Table 1]

For these hydrogen separators (Examples 1 to 9 and Comparative Examples 1 and 2), the measurement results of the amount of helium gas leaked from the hydrogen separation layer after “500 ° C.-50 times heat treatment” described above were obtained as titanium. FIG. 3 shows the relationship with the film thickness. Further, for Example 4 and Comparative Example 1 in which the palladium film thickness is 2.6 μm, and in Example 5 and Comparative Example 2 in which the palladium film thickness is 5.0 μm, before the heat treatment, after the 500 ° C. heat treatment, and 700 ° C. heat treatment. FIG. 4 shows the measurement results of the leakage amount of helium gas from the hydrogen separation layer under each thermal cycle condition after and after the heat treatment at 500 ° C. for 50 times. From these Examples and Comparative Examples, it can be seen that the hydrogen separator of the present invention can maintain the airtightness of the hydrogen separation layer after the heat treatment at a high temperature. Moreover, it turns out that it is especially desirable to make a titanium film thickness into about 0.02 micrometer-0.50 micrometer.
[0069]
As described above, according to the hydrogen separator of the present invention, the hydrogen separation layer interposes a predetermined metal layer having good wettability with the porous substrate on one surface of the porous substrate. Since the predetermined metal layer is interposed between the hydrogen separation layer and the porous substrate, the adhesion between the hydrogen separation layer and the porous substrate can be improved as compared with the case of direct contact between the two. Even when a heat cycle that repeats a high temperature state and a low temperature state is added, peeling and defects of the hydrogen separation layer are less likely to occur and the airtightness and durability are greatly improved as compared with the conventional hydrogen separator.
According to the method for producing a hydrogen separator of the present invention, a predetermined metal layer is disposed on one surface of the porous substrate, and the hydrogen separation layer is plated on the surface of the predetermined metal layer. In order to improve the adhesion between the hydrogen separation layer and the porous substrate by interposing a predetermined metal layer, compared with the case of direct contact between the two, a high temperature state and a low temperature state are provided. Even when a repeated heat cycle is applied, it is difficult to cause separation and defects of the hydrogen separation layer, and a hydrogen separator having greatly improved airtightness and durability can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view taken along a plane perpendicular to a hydrogen separation layer, schematically showing one embodiment of a hydrogen separator of the present invention.
FIG. 2 schematically shows a process of obtaining a hydrogen separator in the method of manufacturing a hydrogen separator according to the present embodiment, and FIG. 2 (a) is a cross-sectional view showing a porous substrate provided with a predetermined metal. FIG. 2B is a cross-sectional view showing the obtained hydrogen separator.
FIG. 3 shows the titanium film thickness and the hydrogen-permeable metal layer gas tightness (helium leakage amount) after “500 ° C.-50 times heat treatment” in the hydrogen separator of the present invention and the hydrogen separator according to the prior art. It is a graph which shows the relationship.
FIG. 4 is a graph showing the relationship between each thermal cycle condition and the gas tightness (helium leakage amount) of the hydrogen selective permeable metal layer in the hydrogen separator of the present invention and the hydrogen separator according to the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,10 ... Hydrogen separator, 2,12 ... Porous base | substrate, 3,13 ... Hydrogen separation layer, 4,14 ... Predetermined metal layer, 5,15 ... One surface.

Claims (14)

A porous substrate having a large number of pores communicating from one surface to the other surface, and only hydrogen in a gas including hydrogen flowing from the one or the other surface side disposed on the porous substrate. A hydrogen separator comprising a hydrogen separation layer capable of selectively permeating and flowing out from the other or one surface side,
The hydrogen separation layer is disposed in a state in which a predetermined metal layer is interposed on the one surface of the porous substrate, and the other or one surface side of hydrogen by interposing the predetermined metal layer. A hydrogen separator characterized in that the adhesion between the hydrogen separation layer and the porous substrate is improved as compared with the case of direct contact between the two without interfering with the outflow from the substrate. The hydrogen separator according to claim 1, wherein the predetermined metal layer is a metal layer made of titanium (Ti). The hydrogen separator according to claim 1 or 2, wherein the porous substrate is mainly composed of ceramic. The hydrogen separator according to claim 1, wherein the hydrogen separation layer is made of a hydrogen selective permeable metal. The hydrogen separator according to claim 4, wherein the hydrogen selective permeable metal is palladium or an alloy containing palladium. The hydrogen separator according to claim 1, wherein the hydrogen separation layer has a thickness of 1 to 5 μm. The hydrogen separator according to claim 1, wherein the predetermined metal layer is formed by a vacuum deposition method. A porous substrate having a large number of pores communicating from one surface to the other surface, and only hydrogen in a gas including hydrogen flowing from the one or the other surface side disposed on the porous substrate. A hydrogen separation layer comprising a hydrogen separation layer capable of selectively permeating and flowing out from the other or one surface side,
A predetermined metal layer is disposed on the one surface of the porous substrate, the hydrogen separation layer is disposed on the surface of the predetermined metal layer by plating, and the hydrogen separation layer and the porous substrate By interposing the predetermined metal layer, the adhesiveness between the two is improved as compared with the case of direct contact between the two without interfering with the outflow of hydrogen from the other or one surface side. A method for producing a hydrogen separator. The method for producing a hydrogen separator according to claim 8, wherein the predetermined metal layer is a metal layer made of titanium (Ti). The method for producing a hydrogen separator according to claim 8 or 9, wherein the porous substrate comprises ceramic as a main component. The method for producing a hydrogen separator according to any one of claims 8 to 10, wherein the hydrogen separation layer is made of a hydrogen selective permeable metal. The method for producing a hydrogen separator according to claim 11, wherein the hydrogen selective permeable metal is palladium or an alloy containing palladium. The method for producing a hydrogen separator according to any one of claims 8 to 12, wherein the hydrogen separation layer has a thickness of 1 to 5 µm. The method for producing a hydrogen separator according to any one of claims 8 to 13, wherein the predetermined metal layer is disposed by a vacuum deposition method.

Images