JP4747737B2 - Hydrogen permeable alloy membrane and method for producing the same - Google Patents
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本発明は、水素透過合金膜及びその製造方法に関し、さらに詳しくは、水素を含む混合ガスから水素を選択的に透過・分離する性能に優れ、燃料電池用の水素ガスの精製・分離装置へ適用でき、安価で水素を多量に吸蔵しても崩壊することがない水素透過合金膜及びその製造方法に関する。 The present invention relates to a hydrogen permeable alloy membrane and a method for producing the same, and more specifically, it has excellent performance of selectively permeating and separating hydrogen from a mixed gas containing hydrogen, and is applied to a hydrogen gas refining and separating apparatus for a fuel cell. The present invention relates to a hydrogen-permeable alloy film that is inexpensive and does not collapse even when a large amount of hydrogen is occluded, and a method for manufacturing the same.
Ｐｄに代表される金属膜、あるいはＰｄを含む合金膜は、水素を選択的に透過・分離する性質を持つため水素透過合金膜として、半導体用シリコン製造等に用いる還元ガス用などの高純度水素精製装置に使用されている。 A metal film typified by Pd or an alloy film containing Pd has a property of selectively permeating and separating hydrogen, and therefore, as a hydrogen permeable alloy film, it is used as a high-purity hydrogen for reducing gas used for manufacturing silicon for semiconductors, etc. Used in purification equipment.
近年、水素透過合金膜は、燃料電池の燃料として用いる水素ガスの精製・分離装置へ適用されるようになった。水素透過合金膜としては、純Ｐｄ、Ｐｄ−Ａｇ、Ｐｄ−ＹなどのＰｄ合金が知られている。 In recent years, hydrogen permeable alloy membranes have been applied to purification / separation devices for hydrogen gas used as fuel for fuel cells. Pd alloys such as pure Pd, Pd—Ag, and Pd—Y are known as hydrogen permeable alloy films.
例えば、Ｐｄとイットリウム及びランタニド（但し、ＬａとＰｒを除く）からなる群から選ばれた一種以上の金属元素との合金が提案されている（特許文献１参照）。また、Ａｇを５〜２５ａｔ％と、ＹまたはＧｄを１〜１０ａｔ％と、残部Ｐｄよりなる合金（特許文献２参照）、さらには、Ｐｄと合金化する金属がＡｇ、Ａｕ、Ｐｔ、Ｒｈ、Ｒｕ、Ｉｒ、Ｃｅ、ＹまたはＧｄであるＰｄ合金膜も提案されている（特許文献３参照）。しかしながら、Ｐｄは貴金属であり材料コストが高いという問題がある。 For example, an alloy of Pd with one or more metal elements selected from the group consisting of yttrium and lanthanide (excluding La and Pr) has been proposed (see Patent Document 1). Further, an alloy consisting of 5 to 25 at% Ag, 1 to 10 at% Y or Gd, and the balance Pd (see Patent Document 2), and further, a metal alloying with Pd is Ag, Au, Pt, Rh, A Pd alloy film that is Ru, Ir, Ce, Y, or Gd has also been proposed (see Patent Document 3). However, there is a problem that Pd is a noble metal and the material cost is high.
そのため、Ｐｄに代わる材料として、Ｎｂ、Ｔａ、Ｖなどの５Ａ金属元素を用いた水素透過合金膜が提案されている（特許文献４参照）。Ｎｂ、Ｔａ、Ｖおよびそれらの合金は、水素透過性能が高く、ＰｄまたはＰｄ合金の１０倍程度の水素透過係数を持つことが知られている。しかしながら、Ｎｂ、Ｔａ、Ｖなどの５Ａ金属は、水素を多量に吸蔵すると膨張し、崩壊してしまうため、Ｎｂ、Ｔａ、Ｖなどの５Ａ金属のみの金属膜では水素透過合金膜として使用できないという問題があった。 Therefore, a hydrogen permeable alloy film using a 5A metal element such as Nb, Ta, V or the like has been proposed as a material to replace Pd (see Patent Document 4). Nb, Ta, V and their alloys are known to have high hydrogen permeation performance and have a hydrogen permeation coefficient about 10 times that of Pd or Pd alloys. However, 5A metal such as Nb, Ta, V expands and collapses when a large amount of hydrogen is occluded, so that a metal film containing only 5A metal such as Nb, Ta, V cannot be used as a hydrogen permeable alloy film. There was a problem.
燃料電池は、最近さまざまな分野で実用化が進んでおり、工場や一般家庭で使用される比較的大型のものだけでなく、自動車などに搭載される小型軽量のものも開発されている。後者のような燃料電池では、水素透過性能が高いだけでなく、安価で、かつ衝撃に対する機械的強度が大きいことも要求されている。 Fuel cells have recently been put into practical use in various fields, and not only relatively large batteries used in factories and general households, but also small and light batteries mounted on automobiles and the like have been developed. Fuel cells such as the latter are required not only to have high hydrogen permeation performance but also to be inexpensive and have high mechanical strength against impact.
そこで、本出願人は、先に、金属粉もしくはセラミック粉を焼結して得られる多孔体の表面に、Ｖ、Ｎｂ、Ｔａのいずれか、或いはこれらの一種とＮｉ、Ｃｏ、又はＭｏから選ばれる一種との合金からなる膜を形成した水素分離材料（特許文献５参照）、さらに、５Ａ金属相が水素を吸蔵し膨張しても膜の骨格を支持して崩壊を防止することができるように、Ｃｕと５Ａ金属を合金化した水素透過合金膜（特許文献６）を提案した。
これにより、水素透過性能が高く、比較的安価な水素透過合金膜を提供することができたが、衝撃に対する機械的強度の面ではまだ十分な性能が得られていなかった。
Therefore, the present applicant first selects one of V, Nb, Ta, or one of these and Ni, Co, or Mo on the surface of the porous body obtained by sintering metal powder or ceramic powder. Separation material (see Patent Document 5) that forms a film made of an alloy with one kind of the above, and even if the 5A metal phase absorbs and expands hydrogen, it can support the skeleton of the film and prevent collapse. In addition, a hydrogen-permeable alloy film (Patent Document 6) in which Cu and 5A metal are alloyed was proposed.
As a result, it was possible to provide a hydrogen permeable alloy film having high hydrogen permeation performance and relatively low cost, but sufficient performance was not yet obtained in terms of mechanical strength against impact.
このような状況下、さらに高い水素透過性能を有し、材料コストが比較的安く、しかも水素を多量に吸蔵しても崩壊することがない水素透過合金膜が望まれていた。
本発明の目的は、水素を含む混合ガスから水素を選択的に透過・分離する性能に優れ、燃料電池用の水素ガスの精製・分離装置へ適用でき、安価で水素を多量に吸蔵しても崩壊することがない水素透過合金膜及びその製造方法を提供することにある。 The object of the present invention is excellent in the performance of selectively permeating and separating hydrogen from a mixed gas containing hydrogen, and can be applied to a hydrogen gas purification / separation device for a fuel cell. An object of the present invention is to provide a hydrogen permeable alloy membrane that does not collapse and a method for manufacturing the membrane.
本発明者らは、前述の課題を解決するために鋭意研究を重ね、水素透過性能が高い５Ａ金属を含む各種合金膜、特に５Ａ金属とＣｕ、またはＡｇとの合金について、水素透過時の挙動を詳細に検討した結果、５Ａ金属が横断面方向に連続した相を形成していると水素吸蔵により体積膨張してクラックが生じることを究明し、それを抑制するには、水素透過部と水素を透過しない部分の構造を微細に制御して、特定量の水素透過部が、水素不透過部をマトリクスとして横断面方向に相互に独立して存在し、縦断面（膜厚）方向には直線的に連続した海島状構造とすることにより、優れた水素透過合金膜として活用できることを見出し、本発明を完成するに至った。 The inventors of the present invention have made extensive studies to solve the above-described problems, and various kinds of alloy films containing 5A metal having high hydrogen permeation performance, particularly alloys of 5A metal and Cu or Ag, can behave at the time of hydrogen permeation. As a result of investigating in detail, it was found that when 5A metal forms a continuous phase in the cross-sectional direction, volume expansion occurs due to hydrogen occlusion and cracks occur. The structure of the part that does not permeate is finely controlled, and a certain amount of hydrogen permeation part exists independently from each other in the cross-sectional direction using the hydrogen non-permeation part as a matrix, and straight in the longitudinal cross-section (film thickness) As a result, the inventors have found that a continuous sea-island structure can be used as an excellent hydrogen-permeable alloy film, and have completed the present invention.
すなわち、本発明の第１の発明によれば、水素を透過する金属材料からなる水素透過部（Ａ）と、水素を透過しない金属材料からなる水素不透過部（Ｂ）とから形成され、かつこれらはお互いに隣接しながら複合化して海島状構造をなす膜厚が１〜５０μｍの水素透過合金膜であって、水素透過部（Ａ）は、水素不透過部（Ｂ）からなるマトリックス中で、膜厚方向に対して連続的に線状で連繋するが、横断面方向に対して相互に独立して微細に分散し、水素透過部（Ａ）の直径が、横断面を円に換算したとき、１５μｍ以下であって、かつ、水素透過部（Ａ）の割合は、膜全体に対して体積率基準で１５〜８０％であり、さらに、水素透過合金膜の両表面に、膜厚が０．０１〜１μｍのＰｄ膜が被覆されていることを特徴とする水素透過合金膜が提供される。 That is, according to the first aspect of the present invention, a hydrogen permeable portion (A) made of a metal material that permeates hydrogen and a hydrogen impermeable portion (B) made of a metal material that does not permeate hydrogen, and These are hydrogen-permeable alloy membranes having a film thickness of 1 to 50 μm that are complexed adjacent to each other to form a sea-island structure, and the hydrogen-permeable portion (A) is in a matrix composed of hydrogen-impermeable portions (B). The film is continuously linearly connected to the film thickness direction, but finely dispersed independently from each other in the transverse direction, and the diameter of the hydrogen permeation part (A) is converted into a circle in the transverse section. when, there is 15μm or less, and the ratio between the hydrogen permeable portion (a) is Ri 15-80% der by volume based on the entire film, further, on the both surfaces of the hydrogen permeable alloy film thickness hydrogen permeation alloy but, wherein a Pd film 0.01~1μm is covered There is provided.
また、本発明の第２の発明によれば、第１の発明において、水素を透過する金属材料が、Ｎｂ、ＴａおよびＶの群から選ばれる少なくとも１種の５Ａ族金属であり、その含有量が９０％以上であることを特徴とする水素透過合金膜が提供される。 According to the second invention of the present invention, in the first invention, the metal material that permeates hydrogen is at least one group 5A metal selected from the group of Nb, Ta, and V, and the content thereof The hydrogen permeation alloy membrane is characterized in that is 90% or more.
また、本発明の第３の発明によれば、第１の発明において、水素を透過しない金属材料が、Ｃｕ、またはＡｇであり、その含有量が９０％以上であることを特徴とする水素透過合金膜が提供される。 According to a third aspect of the present invention, in the first aspect, the metal material that does not transmit hydrogen is Cu or Ag, and the content thereof is 90% or more. An alloy film is provided.
一方、本発明の第４の発明によれば、第１〜３のいずれかの発明に係り、水素透過部（Ａ）となる金属材料を水素不透過部（Ｂ）となる金属材料によって被覆して棒状の複合母材を作製し、次に、この棒状の複合母材を延伸し、水素透過部（Ａ）が水素不透過部（Ｂ）のマトリクス中に微細に分散した線状の複合母材とし、その後、この線状の複合母材を束ねて、水素透過部（Ａ）の直径が、横断面を円に換算したとき、１５μｍ以下となるように複合化した後に、所定の長さに切断して、その切断面を研磨し、厚さが１〜５０μｍとなった水素透過合金膜の両表面に、膜厚が０．０１〜１μｍのＰｄ膜を被覆することを特徴とする水素透過合金膜の製造方法が提供される。 On the other hand, according to the fourth invention of the present invention, according to any one of the first to third inventions, the metal material that becomes the hydrogen permeable portion (A) is covered with the metal material that becomes the hydrogen non-permeable portion (B). A rod-shaped composite base material is produced, and then the rod-shaped composite base material is stretched, and a linear composite base material in which the hydrogen permeation part (A) is finely dispersed in the matrix of the hydrogen non-permeation part (B). and wood, then by bundling the linear composite preform, the hydrogen permeation section diameter of (a), when converted to cross-section in a circular, after complexed so as to 15μm or less, a predetermined length Then, the cut surface is polished , and both surfaces of the hydrogen permeable alloy film having a thickness of 1 to 50 μm are coated with a Pd film having a thickness of 0.01 to 1 μm. A method for producing a hydrogen permeable alloy membrane is provided.
また、本発明の第５の発明によれば、第４の発明において、水素透過部（Ａ）となる金属材料の形状が、棒状であることを特徴とする水素透過合金膜の製造方法が提供される。 According to a fifth aspect of the present invention, there is provided the method for producing a hydrogen permeable alloy film according to the fourth aspect , wherein the shape of the metal material to be the hydrogen permeable portion (A) is a rod shape. Is done.
また、本発明の第６の発明によれば、第４の発明において、延伸された棒状の複合母材が、水素不透過部（Ｂ）となる金属材料により被覆され、その後、熱間押出し、または伸線加工されることを特徴とする水素透過合金膜の製造方法が提供される。 According to the sixth invention of the present invention, in the fourth invention, the stretched rod-shaped composite base material is coated with a metal material that becomes the hydrogen-impermeable portion (B), and then hot-extruded, Alternatively, a method for producing a hydrogen permeable alloy film characterized by being drawn.
さらに、本発明の第７の発明によれば、第４〜６のいずれかの発明において、棒状の複合母材が所定の直径の線状複合母材になるまで、延伸、被覆、及び熱間押出し、あるいは伸線加工を繰り返し行うことを特徴とする水素透過合金膜の製造方法が提供される。 Furthermore, according to the seventh invention of the present invention, in any one of the fourth to sixth inventions, the rod-like composite base material is stretched, covered, and heated until it becomes a linear composite base material having a predetermined diameter. There is provided a method for producing a hydrogen permeable alloy film characterized by repeatedly performing extrusion or wire drawing.
本発明の水素透過合金膜は、水素透過部と水素を透過しない部分の金属材料が微細に構造制御された水素透過合金膜であって、特定量の水素透過部がＮｂ、Ｔａ、およびＶの群から選ばれる少なくとも１種の５Ａ族合金で、これが水素を透過しないＣｕあるいはＡｇとを含むマトリクス中に均一に分散し、膜厚方向に線状に連続している合金膜であることから、水素透過性能に優れ、しかも水素透過条件においても崩壊せずに長時間使用できる。
また、本発明の水素透過合金膜は、金属材料の塑性加工によって容易に低コストで製造できる。そのため、燃料電池用をはじめ各種装置の水素透過合金膜として利用することができるから、その工業的価値は極めて大きい。
The hydrogen permeable alloy film of the present invention is a hydrogen permeable alloy film in which the metal material of the hydrogen permeable portion and the portion that does not transmit hydrogen is finely controlled, and a specific amount of hydrogen permeable portion is made of Nb, Ta, and V. At least one 5A group alloy selected from the group, which is an alloy film that is uniformly dispersed in a matrix containing Cu or Ag that does not transmit hydrogen, and is linearly continuous in the film thickness direction. It has excellent hydrogen permeation performance and can be used for a long time without collapsing under hydrogen permeation conditions.
Further, the hydrogen permeable alloy film of the present invention can be easily manufactured at low cost by plastic working of a metal material. Therefore, since it can be used as a hydrogen permeable alloy membrane for various devices including fuel cells, its industrial value is extremely large.
以下、本発明の水素透過合金膜及びその製造方法について、図面を用いて詳しく説明する。 Hereinafter, the hydrogen-permeable alloy film and the manufacturing method thereof of the present invention will be described in detail with reference to the drawings.
１．水素透過合金膜
本発明の水素透過合金膜は、水素を透過する金属材料が水素を透過しない金属材料のマトリクス中に微細に分散し複合化した膜であって、水素を透過する金属材料からなる水素透過部が、膜厚方向には連続しており、横断面方向には不連続であることを特徴とする。
すなわち、水素を透過する金属材料からなる水素透過部（Ａ）と、水素を透過しない金属材料からなる水素不透過部（Ｂ）とから形成され、かつこれらはお互いに隣接しながら複合化して海島状構造をなす膜厚が１〜５０μｍの水素透過合金膜であって、水素透過部（Ａ）は、水素不透過部（Ｂ）からなるマトリックス中で、膜厚方向に対して連続的に線状で連繋するが、横断面方向に対して相互に独立して微細に分散し、水素透過部（Ａ）の直径が、横断面を円に換算したとき、１５μｍ以下であって、かつ、水素透過部（Ａ）の割合は、膜全体に対して体積率基準で１５〜８０％であり、さらに、水素透過合金膜の両表面に、膜厚が０．０１〜１μｍのＰｄ膜が被覆されていることを特徴とする。
1. Hydrogen permeable alloy film The hydrogen permeable alloy film of the present invention is a film in which a metal material that permeates hydrogen is finely dispersed and combined in a matrix of a metal material that does not permeate hydrogen, and is made of a metal material that permeates hydrogen. The hydrogen permeable portion is continuous in the film thickness direction and discontinuous in the cross-sectional direction.
That is, it is formed of a hydrogen permeable portion (A) made of a metal material that permeates hydrogen and a hydrogen impermeable portion (B) made of a metal material that does not permeate hydrogen. A hydrogen permeable alloy film having a film thickness of 1 to 50 μm and having a film- like structure, wherein the hydrogen permeable portion (A) is a continuous line in the film thickness direction in the matrix composed of the hydrogen impermeable portion (B). However, the hydrogen permeation part (A) has a diameter of 15 μm or less when the cross section is converted into a circle when the cross section is converted into a circle. ratio of the transmission portion (a) is Ri 15-80% der by volume based on the entire film, further, on the both surfaces of the hydrogen permeable alloy film thickness is Pd film 0.01~1μm coating It is characterized by being.
この水素透過合金膜の断面を図１の写真に示す。図１（左上）がＳＥＭで撮影した水素透過合金膜の横断面、その右の写真は、一部を拡大したものである。また、図１（左下）は、水素透過合金膜の縦断面を示したものである。楕円形で平滑な状態に写っているのがＮｂ、小さな凹凸がある状態で写っているのがＣｕである。平滑な状態のＮｂの相と、小さな凹凸がある状態のＣｕの相が複合化した水素透過合金膜の横断面をみると、平滑な状態のＮｂ相が水平方向に連続していることが分かる。 A cross section of this hydrogen permeable alloy membrane is shown in the photograph of FIG. FIG. 1 (upper left) is a cross-sectional view of a hydrogen permeable alloy film taken with an SEM, and a photograph on the right is a partially enlarged view. FIG. 1 (lower left) shows a longitudinal section of the hydrogen permeable alloy film. Nb is in an oval and smooth state, and Cu is in a state with small irregularities. Looking at the cross section of the hydrogen permeable alloy film in which the smooth Nb phase and the Cu phase with small irregularities are combined, it can be seen that the smooth Nb phase is continuous in the horizontal direction. .
本発明において水素透過部は、このように膜厚方向には連続しており、横断面方向には不連続である。膜が水素を透過するためには、水素透過部の相が膜厚方向に連続していなければならない。前記したとおり、水素透過部は、水素を吸蔵すると体積膨張を起こす。このとき、ひずみが生じそれが大きくなると、水素透過部内また水素を透過しない部分との界面で割れてしまい、ガス漏れを生じ、また、水素透過部が横断面方向に連続していると体積変化による割れが、遠方まで進行してしまうためである。本発明の水素透過合金膜は、水素透過部を膜の横断面方向には不連続となるように配置することで、割れの進行を抑制したものである。 In the present invention, the hydrogen permeation portion is thus continuous in the film thickness direction and discontinuous in the cross-sectional direction. In order for the membrane to transmit hydrogen, the phase of the hydrogen permeable portion must be continuous in the film thickness direction. As described above, the hydrogen permeable part expands when it absorbs hydrogen. At this time, when strain is generated and becomes large, cracking occurs at the interface between the hydrogen permeable part and the part that does not transmit hydrogen, gas leakage occurs, and the volume change when the hydrogen permeable part is continuous in the cross-sectional direction. This is because the cracks due to will progress far away. In the hydrogen permeable alloy membrane of the present invention, the progress of cracking is suppressed by disposing the hydrogen permeable portion so as to be discontinuous in the cross-sectional direction of the membrane.
本発明の水素透過合金膜は、Ｎｂ、Ｔａ、およびＶの群から選ばれる少なくとも１種の５Ａ族金属からなる水素透過部の相が、ＣｕまたはＡｇを含むマトリクス金属からなる水素不透過部の相に微細に分散して複合化された膜である。
本発明において水素を透過する金属材料は、Ｎｂ、ＴａおよびＶの群から選ばれる少なくとも１種の５Ａ族金属であり、それを９０％以上含有する。これら５Ａ金属は、単独でもよいが、これら金属２種以上の合金でもよい。すなわち、合金には、Ｎｂ−Ｔａ、Ｎｂ−Ｖ、Ｔａ−Ｖ、あるいはＮｂ−Ｔａ−Ｖの各種合金が含まれる。これら５Ａ族金属が９０％以上含有されていないと満足すべき水素透過性能が得られない。
また、水素を透過しない金属材料は、Ｃｕ、またはＡｇであり、それを９０％以上含有する。これら金属は、単独でもよいが、これら２種からなる合金でもよい。Ｃｕ、またはＡｇが９０％以上含有されていないと、クラックが発生し、機械的強度が低下して、満足すべき水素透過性能が得られない。
The hydrogen permeable alloy film of the present invention has a hydrogen permeable portion made of a matrix metal containing Cu or Ag in a phase of a hydrogen permeable portion made of at least one group 5A metal selected from the group consisting of Nb, Ta, and V. It is a film that is finely dispersed in a phase and combined.
In the present invention, the metal material that transmits hydrogen is at least one group 5A metal selected from the group consisting of Nb, Ta, and V, and contains 90% or more thereof. These 5A metals may be used alone or as an alloy of two or more of these metals. That is, the alloys include various alloys of Nb—Ta, Nb—V, Ta—V, or Nb—Ta—V. If these 5A group metals are not contained in 90% or more, satisfactory hydrogen permeation performance cannot be obtained.
Moreover, the metal material which does not permeate | transmit hydrogen is Cu or Ag, and contains 90% or more of it. These metals may be used alone or as an alloy composed of these two kinds. If 90% or more of Cu or Ag is not contained, cracks are generated, the mechanical strength is lowered, and satisfactory hydrogen permeation performance cannot be obtained.
本発明においては、５Ａ金属を主成分とする５Ａ金属相からなる水素透過部と、Ｃｕ、Ａｇを主成分とする相からなる水素不透過部の２相が共存している。ＣｕあるいはＡｇと５Ａ金属の固溶限は、互いに非常に小さいので、合金膜中でＣｕ相と５Ａ金属相の２相が存在する。そして、Ｎｂ、Ｔａ、およびＶの群から選ばれる少なくとも１種の５Ａ族金属相は、高い水素吸蔵性を有するが、ＣｕあるいはＡｇ相は、水素を透過しないので、水素を吸蔵し膨張した５Ａ金属相を支持して崩壊を防止する。そして、水素透過部が膜横断面方向に不連続であることにより、水素吸蔵による体積膨張による歪みを抑制することができる。
このように合金膜には、水素透過部に５Ａ金属と、水素不透過部にＣｕあるいはＡｇが含まれなければならないが、本発明の目的を損なわない限り、水素不透過部には、Ｎｉ、Ｃｏ、Ｍｏ、Ｆｅなどの金属が少量含まれていても構わない。但し、Ｎｉ、Ｃｏ、Ｍｏ、あるいはＦｅなどの含有量が５ｗｔ％を超えると、同等の水素透過性能を得るためにはＣｕの含有量を減らさざるをえなくなり、機械的強度が低下するので好ましくない。なお、その他不純物として、製造上不可避な元素が１０ｐｐｍ程度含まれても差し支えない。
In the present invention, two phases of a hydrogen permeable portion composed of a 5A metal phase mainly composed of 5A metal and a hydrogen non-permeable portion composed of a phase mainly composed of Cu and Ag coexist. Since the solid solubility limit of Cu or Ag and 5A metal is very small, there are two phases of Cu phase and 5A metal phase in the alloy film. At least one 5A group metal phase selected from the group consisting of Nb, Ta, and V has a high hydrogen storage property, but the Cu or Ag phase does not permeate hydrogen, so it has expanded by absorbing hydrogen and expanding 5A. Support the metal phase to prevent collapse. And since the hydrogen permeation | transmission part is discontinuous in the film cross-sectional direction, the distortion by the volume expansion by hydrogen occlusion can be suppressed.
Thus, the alloy film must contain 5A metal in the hydrogen permeable portion and Cu or Ag in the hydrogen impermeable portion. However, unless the purpose of the present invention is impaired, the hydrogen impermeable portion includes Ni, A small amount of metals such as Co, Mo, and Fe may be contained. However, if the content of Ni, Co, Mo, Fe or the like exceeds 5 wt%, the Cu content must be reduced to obtain equivalent hydrogen permeation performance, and the mechanical strength is decreased, which is preferable. Absent. In addition, as an impurity, about 10 ppm of elements inevitable in production may be contained.
本発明は、水素透過部と水素を透過しない部分の構成を制御することで、水素透過部の体積率を従来の膜よりも増やすことを意図している。水素透過部を構成する相は、その周りに水素を透過しない金属材料で構成される相で取り囲まれ、相互に分断されていればよい。
水素を透過する金属材料は、体積率にして１５〜８０％でなければならず、特に４０〜７０％であることが好ましい。水素を透過する金属材料が１５％以下では、水素透過性能が不十分となってしまう。その体積率は高いほうが、水素透過量は大きくなり望ましいが、８０％を超えると水素を透過する際に、膜を構成する５Ａ金属相を十分に支持できなくなり、水素吸蔵による膜の崩壊を防止することが困難となる。
The present invention intends to increase the volume ratio of the hydrogen permeable portion as compared with the conventional membrane by controlling the configuration of the hydrogen permeable portion and the portion that does not transmit hydrogen. The phases constituting the hydrogen permeation part may be surrounded by a phase composed of a metal material that does not permeate hydrogen and separated from each other.
The metal material which permeates hydrogen must be 15 to 80% by volume, and preferably 40 to 70%. If the metal material that permeates hydrogen is 15% or less, the hydrogen permeation performance is insufficient. The higher the volume ratio, the larger the hydrogen permeation amount, which is desirable, but when it exceeds 80%, the 5A metal phase that constitutes the membrane cannot be sufficiently supported when hydrogen is permeated, preventing the membrane from collapsing due to hydrogen occlusion. Difficult to do.
水素透過部（それを構成する金属材料の相）は、横断面での直径が円に換算して１５μｍ以下となるようにする。好ましい直径は１０μｍ以下であり、さらに好ましくは５μｍ以下である。１５μｍ以下とするのは、水素透過部が水素を透過しないＣｕなどの延性金属で分割され、水素吸蔵による体積膨張を緩和するが、それでも個々の水素透過部の直径が大きいと歪みが大きくなり、割れが生じてしまうためである。 The hydrogen permeation portion (the phase of the metal material constituting the hydrogen permeation portion) is made to have a diameter in a cross section of 15 μm or less in terms of a circle . The preferred diameter is at 10μm or less, more preferably 5μm or less. 15 μm or less is that the hydrogen permeation part is divided by a ductile metal such as Cu that does not permeate hydrogen and relaxes the volume expansion due to hydrogen occlusion, but still the strain increases when the diameter of each hydrogen permeation part is large, This is because cracks occur.
これに対して、水素を透過しない金属材料は、体積率にして２０〜８５％でなければならず、特に３０〜６０％が好ましい。これが２０％未満では、水素透過部を構成する５Ａ金属相を十分に支持できなくなり、水素吸蔵による膜の崩壊を防止できない。また、８５％を超えると、５Ａ金属相の優れた水素透過性能が不十分となってしまう。 On the other hand, the metal material which does not permeate hydrogen must be 20 to 85% in volume ratio, and preferably 30 to 60%. If this is less than 20%, the 5A metal phase constituting the hydrogen permeable part cannot be sufficiently supported, and the film cannot be prevented from collapsing due to hydrogen occlusion. If it exceeds 85%, the excellent hydrogen permeation performance of the 5A metal phase will be insufficient.
また、水素透過合金膜の膜厚は、１〜５０μｍであり、特に１〜３０μｍであることが好ましい。水素ガスは、水素透過合金膜が薄いほど多量に流れるから、膜の膜厚は５０μｍ以下であることが必要である。また、膜厚が５０μｍを超えると、強度は上昇するものの水素透過量が大幅に低減するので好ましくない。しかし、膜厚が１μｍよりも薄いと機械的強度が不足して膜が破損してしまい、未精製の水素ガスが漏れてしまう。 The film thickness of the hydrogen permeable alloy film is 1 to 50 μm, and preferably 1 to 30 μm. Since hydrogen gas flows in a larger amount as the hydrogen permeable alloy film is thinner, the film thickness needs to be 50 μm or less. On the other hand, when the film thickness exceeds 50 μm, although the strength increases, the hydrogen permeation amount is greatly reduced, which is not preferable. However, if the film thickness is less than 1 μm, the mechanical strength is insufficient, the film is damaged, and unpurified hydrogen gas leaks.
また、水素透過合金膜の直径は、特に制限されるわけではないが、５ｍｍ以上であり、さらには２５ｍｍ以上であることが好ましい。水素透過合金膜の直径が大きいほど水素ガスが多量に流れるためである。 The diameter of the hydrogen permeable alloy membrane is not particularly limited, but is 5 mm or more, and more preferably 25 mm or more. This is because a larger amount of hydrogen gas flows as the diameter of the hydrogen permeable alloy film increases.
この水素透過合金膜を構成している５Ａ金属は酸化されやすく、この５Ａ金属相の表面が酸化されると水素透過の障壁となってしまう。そこで、本発明では、その合金膜の両表面に水素は透過するが実質的に酸素を透過しないＰｄ膜を被覆する。Ｐｄを含む酸化防止膜をその表面に形成して、Ｐｄ膜／合金膜／Ｐｄ膜とする。また、Ｐｄ膜の替わりに水素透過Ｐｄ合金として既知のＰｄ−Ａｇ、Ｐｄ−Ｃｕ、Ｐｄ−ＹおよびＰｄ−希土類合金であってもかまわない。
水素透過合金膜の両表面に被覆されたＰｄ膜は、水素ガス分子を解離して合金膜の中へ溶解させ、また、反対表面では水素ガス分子として再結合させるための触媒層として働き、しかも水素透過合金膜が酸化して劣化するのを防止する効果をもつ。
Ｐｄ膜の膜厚は、０．０１〜１μｍであり、特に０．０３〜０．８μｍが好ましい。Ｐｄ膜厚が０．０１μｍ未満ではＣｕや５Ａ金属などに対する酸化防止が不十分であり、１μｍよりも厚いと材料コストが高くなるため好ましくない。
The 5A metal constituting the hydrogen permeable alloy film is easily oxidized, and when the surface of the 5A metal phase is oxidized, it becomes a barrier for hydrogen permeation. Therefore, in the present invention, both surfaces of the alloy film are coated with a Pd film that transmits hydrogen but does not substantially transmit oxygen. An antioxidant film containing Pd is formed on the surface to obtain Pd film / alloy film / Pd film. Further, Pd—Ag, Pd—Cu, Pd—Y, and Pd—rare earth alloys known as hydrogen permeable Pd alloys may be used instead of the Pd film.
The Pd film coated on both surfaces of the hydrogen permeable alloy film acts as a catalyst layer for dissociating and dissolving hydrogen gas molecules into the alloy film and recombining them as hydrogen gas molecules on the opposite surface. It has the effect of preventing the hydrogen permeable alloy film from being oxidized and deteriorated.
The thickness of the Pd film is 0.01 to 1 μm, and 0.03 to 0.8 μm is particularly preferable. If the Pd film thickness is less than 0.01 μm, the oxidation protection against Cu, 5A metal, etc. is insufficient, and if it is thicker than 1 μm, the material cost increases, which is not preferable.
本発明の水素透過合金膜は、それ自体で十分な機械的強度を有するものであるが、必要に応じて、通気性多孔質金属を支持体として用いることができる。
通気性多孔質金属の支持体を金属粒子または金属繊維の焼結体で構成すれば、機械的強度を一層大きくすることができる。金属粒子または金属繊維として、ステンレスまたはニッケル基合金などの素材を用いれば、耐熱性、耐食性、耐水素脆化の特性を改善することもできる。なかでも相対密度５５〜７５％、特に６０〜７０％の多孔質金属基板が好ましい。多孔質金属支持体の材料と相対密度は、通気性と機械的強度を考慮して選択される。相対密度が５５％未満では機械的強度が不十分であり、一方、７５％を超えると通気性が低下することがある。
The hydrogen permeable alloy membrane of the present invention itself has sufficient mechanical strength, but if necessary, a breathable porous metal can be used as a support.
If the air-permeable porous metal support is composed of a sintered body of metal particles or metal fibers, the mechanical strength can be further increased. If a material such as stainless steel or a nickel-based alloy is used as the metal particles or metal fibers, the properties of heat resistance, corrosion resistance, and hydrogen embrittlement resistance can be improved. Among these, a porous metal substrate having a relative density of 55 to 75%, particularly 60 to 70% is preferable. The material and relative density of the porous metal support are selected in consideration of air permeability and mechanical strength. If the relative density is less than 55%, the mechanical strength is insufficient. On the other hand, if the relative density exceeds 75%, the air permeability may be lowered.
２．水素透過合金膜の製造方法
本発明は、上記の膜厚方向には連続し、横断面方向には不連続である水素透過部が水素を透過しない金属材料からなるマトリクス中に微細に分散して複合化した水素透過合金膜を製造する方法である。
すなわち、水素透過部（Ａ）となる金属材料を水素不透過部（Ｂ）となる金属材料によって被覆して棒状の複合母材を作製し、次に、この棒状の複合母材を延伸し、水素透過部（Ａ）が水素不透過部（Ｂ）のマトリクス中に微細に分散した線状の複合母材とし、その後、この線状の複合母材を束ねて、水素透過部（Ａ）の直径が、横断面を円に換算したとき、１５μｍ以下となるように複合化した後に、所定の長さに切断して、その切断面を研磨し、厚さが１〜５０μｍとなった水素透過合金膜の両表面に、膜厚が０．０１〜１μｍのＰｄ膜を被覆することを特徴とする。
2. The present invention relates to a method for producing a hydrogen permeable alloy film, wherein the hydrogen permeable portion that is continuous in the film thickness direction and is discontinuous in the transverse direction is finely dispersed in a matrix made of a metal material that does not transmit hydrogen. This is a method for producing a composite hydrogen permeable alloy membrane.
That is, a metal material to be the hydrogen permeable portion (A) is covered with a metal material to be the hydrogen non-permeable portion (B) to produce a rod-shaped composite base material, and then the rod-shaped composite base material is stretched, The hydrogen permeation part (A) is a linear composite base material finely dispersed in the matrix of the hydrogen non-permeation part (B), and then the linear composite base material is bundled to form the hydrogen permeation part (A). hydrogen diameter, when converted cross section in a circle, that after composite so that 15μm or less, and cut to a predetermined length, polishing the cut surface, the thickness became 1~50μm A Pd film having a thickness of 0.01 to 1 μm is coated on both surfaces of the permeable alloy film .
このような海島状構造を有する水素透過合金膜を製造する方法としては、たとえば、塑性加工法、粉末冶金法のいずれか、あるいは塑性加工法と粉末冶金法とを組み合せた方法により複合母材を作製し、Ｎｂ、ＴａおよびＶの群から選ばれる少なくとも１種の５Ａ族金属とＣｕあるいはＡｇを含有する合金母材を複合化し、水素透過部の直径が円換算で１５μｍ以下とした後に、複合母材を切断研磨して１〜５０μｍの膜厚とする方法が挙げられる。
基本的には、水素を透過する５Ａ金属の線材を、Ｃｕ、Ａｇマトリクスで被覆し、それを塑性加工することで断面積を減じてゆき、その直径を１５μｍ以下とする。そのとき加工方向には延伸されるので、これを加工方向に切断することにより、膜横断面方向には不連続で、膜厚方向には連続である水素透過部を持つ複合化された水素透過合金膜が得られるのである。
As a method for producing a hydrogen permeable alloy film having such a sea-island structure, for example, a composite base material is formed by either a plastic working method, a powder metallurgy method, or a combination of a plastic working method and a powder metallurgy method. The composite material is manufactured and compounded with at least one 5A group metal selected from the group of Nb, Ta and V and an alloy base material containing Cu or Ag, and the diameter of the hydrogen permeation portion is reduced to 15 μm or less in terms of a circle. A method of cutting and polishing the base material to obtain a film thickness of 1 to 50 μm can be mentioned.
Basically, a 5A metal wire that permeates hydrogen is coated with a Cu, Ag matrix, and plastically processed to reduce the cross-sectional area, and the diameter is made 15 μm or less. At that time, since it is stretched in the processing direction, by cutting it in the processing direction, a composite hydrogen permeation having a hydrogen permeation portion that is discontinuous in the film cross-sectional direction and continuous in the film thickness direction. An alloy film is obtained.
複合母材は、塑性加工または粉末冶金法、またそれらの方法の組み合わせで作製することができる。先ず、一本以上の５Ａ金属材料を用意し、ＣuまたはＡｇのマトリクス中に埋め込む。水素透過部となる５Ａ金属材料の形状は棒状であり、本数は数十本以上、特に数百本以上であることが好ましい。これにより、５Ａ金属材料が水素不透過部となるＣuまたはＡｇからなる金属材料のマトリクスで被覆される。得られた棒状複合母材は、押し出し、溝ロール、ダイス線引きなどで延伸される。棒状複合母材は、所定の長さに切断され、ＣuまたはＡｇのパイプ状金属材料に挿入される。次に、これを熱間押し出しあるいは伸線加工により細線化する。
この延伸、被覆、及び熱間押し出し、あるいは伸線加工の一部または全ての工程を繰り返す。これにより、円換算直径にして１５μｍ以下である５Ａ金属部からなる水素透過部が、Ｃｕ、またはＡｇのマトリクスからなる水素不透過部に埋め込まれた細線状の複合母材を容易に得ることができる。細線状の複合母材を束ねて複合化し、所定の直径になった後、この複合材を切断研磨することで、水素透過合金膜を得ることができる。また、最初の段階で棒状の５Ａ金属の代わりに粉末を用いても、粉末冶金法により同様の構造を得ることができる。
The composite base material can be produced by plastic working or powder metallurgy, or a combination of these methods. First, one or more 5A metal materials are prepared and embedded in a matrix of Cu or Ag. The shape of the 5A metal material to be the hydrogen permeable portion is rod-shaped, and the number is preferably several tens or more, particularly preferably several hundred or more. As a result, the 5A metal material is covered with a matrix of a metal material made of Cu or Ag which becomes the hydrogen-impermeable portion. The obtained rod-shaped composite base material is stretched by extrusion, groove roll, die drawing or the like. The rod-shaped composite base material is cut into a predetermined length and inserted into a Cu or Ag pipe-shaped metal material. Next, this is thinned by hot extrusion or wire drawing.
This stretching, coating, hot extrusion, or part or all of the wire drawing process is repeated. As a result, it is possible to easily obtain a thin composite base material in which a hydrogen permeable portion made of a 5A metal portion having a diameter in terms of a circle of 15 μm or less is embedded in a hydrogen impermeable portion made of a matrix of Cu or Ag. it can. A thin wire-shaped composite base material is bundled and combined to obtain a predetermined diameter, and then the composite material is cut and polished to obtain a hydrogen permeable alloy film. Even if powder is used instead of the rod-like 5A metal in the first stage, a similar structure can be obtained by powder metallurgy.
より具体的には、先ず高純度のニオブ棒（例えば、３ｍｍ径）を用意し、これを高純度のＣｕマトリクス中に埋め込む。用いるニオブ棒の本数は、その直径によって適宜決定される。細いニオブ棒を１００本以上用いることが生産上能率的である。埋め込み方法には、外径が円形または六角形にＣｕ管にはめ込むのが簡便である。六角形状にすると、充填性が高い。あるいはＣｕを溶融状態にしておき、この中にニオブ棒を挿入して、Ｃｕを凝固させ、ニオブ棒が１ｍｍ以上の厚さのＣｕで覆われるようにしてもよい。この場合はニオブ／Ｃｕ界面が清浄で、介在物を巻き込みにくく高い密着性が期待できる。このとき、Ｃｕの厚さが均等になるようにすることが好ましい。このときは次に、Ｃｕで被覆された状態のニオブ複合母材を円形または六角形に旋削加工する。このときのニオブ棒の径とＣｕ被覆層の面積率は、最終の水素透過面積を考慮して決められる。またニオブ棒の代わりに、ニオブ粉末を用いることができる。その場合は、例えば、内径が３ｍｍ、厚さ０．５ｍｍのＣｕパイプを用意し、この中にニオブ粉末を充填し突き固める。粉末は、できるだけ微細なものが充填密度を向上できるので好ましい。
このようにして作製したＣｕ被覆ニオブ棒をＣｕビレットにキャニングして、熱間押し出しする。キャニングする被覆棒材の数は押し出し機の能力によるが、数百から数千本が可能である。押し出し比は１５程度が可能である。これをさらに必要に応じて、冷間加工して細線化することにより、1〜３ｍｍ程度の複合線材を得る。この中にはニオブ線がもとのビレットの直径との比に対応した細線となっている。例えば、１６００本を複合した２００ｍｍビレットを押し出し、伸線加工して１ｍｍとするとニオブ線は約１５μｍとなる。
More specifically, a high-purity niobium rod (for example, 3 mm diameter) is first prepared and embedded in a high-purity Cu matrix. The number of niobium rods to be used is appropriately determined depending on the diameter. It is efficient in production to use 100 or more thin niobium bars. As an embedding method, it is convenient to fit the Cu tube into a circular or hexagonal outer diameter. When the hexagonal shape is used, the filling property is high. Alternatively, Cu may be in a molten state, and a niobium rod may be inserted therein to solidify the Cu so that the niobium rod is covered with Cu having a thickness of 1 mm or more. In this case, the niobium / Cu interface is clean, and inclusions are difficult to entrain and high adhesion can be expected. At this time, it is preferable to make the thickness of Cu uniform. Next, the niobium composite base material coated with Cu is turned into a circular shape or a hexagonal shape. At this time, the diameter of the niobium rod and the area ratio of the Cu coating layer are determined in consideration of the final hydrogen permeation area. Niobium powder can be used instead of the niobium rod. In that case, for example, a Cu pipe having an inner diameter of 3 mm and a thickness of 0.5 mm is prepared, and niobium powder is filled into the Cu pipe and hardened. A powder that is as fine as possible is preferable because the packing density can be improved.
The Cu-coated niobium rod thus prepared is canned into a Cu billet and extruded hot. The number of covered bars to be canned depends on the capacity of the extruder, but can range from hundreds to thousands. The extrusion ratio can be about 15. If necessary, this is further subjected to cold working to make a thin wire, thereby obtaining a composite wire of about 1 to 3 mm. Among these, the niobium wire is a thin wire corresponding to the ratio of the diameter of the original billet. For example, when a 200 mm billet composed of 1600 composites is extruded and drawn to 1 mm, the niobium wire is about 15 μm.
また比較的小さなものを作る別の方法として、Ｃｕ被覆ニオブ棒を冷間加工で製造することも可能である。例えば、外径８ｍｍ、ニオブ径７ｍｍのＣｕ被覆ニオブ棒を冷間加工により１ｍｍ径とする。これを例えば１００ｍｍの長さに切り出し、３００本を内径２５ｍｍ、肉厚０．５ｍｍのＣｕ管に挿入して、これを溝ロールにより伸ばし、直径４ｍｍ程度とし、さらにダイス線引きして、直径１ｍｍ程度の複合線材とする。
この複合線材を先ほどと同様にＣｕ管に挿入し、炉内に装入し焼鈍する。焼鈍の条件は、特に限定されるわけではないが、真空中、６００〜１２００℃の温度とすることが好ましい。この条件で、０．５〜５時間焼鈍することによって、複合線材間の空隙をＣｕが埋めることになり合金を形成する。上記の要領で溝ロールおよびダイス線引きし、複合線材とする工程、すなわち延伸、被覆、及び熱間押し出し、あるいは伸線加工を繰り返す。こうして、直径が円換算で３〜１５μｍの５Ａ金属線がＣｕマトリクスの中に複合化された、直径が５〜２０ｍｍの合金棒材とすることができる。さらに大きな直径の試料を得る場合には、これらをさらに複合化しＨＩＰ処理することにより、直径が１００ｍｍ以上の合金棒材とすることができる。
As another method for producing a relatively small one, a Cu-coated niobium rod can be manufactured by cold working. For example, a Cu-coated niobium rod having an outer diameter of 8 mm and a niobium diameter of 7 mm is made 1 mm by cold working. This is cut into a length of, for example, 100 mm, 300 pieces are inserted into a Cu tube having an inner diameter of 25 mm and a wall thickness of 0.5 mm, and this is stretched by a groove roll to have a diameter of about 4 mm, and further dies are drawn to have a diameter of about 1 mm. The composite wire.
This composite wire is inserted into a Cu tube in the same manner as described above, charged in a furnace, and annealed. The annealing conditions are not particularly limited, but are preferably set to a temperature of 600 to 1200 ° C. in a vacuum. By annealing for 0.5 to 5 hours under these conditions, the gap between the composite wires is filled with Cu, and an alloy is formed. In the above-described manner, the process of drawing a groove roll and a die to form a composite wire, that is, stretching, coating, hot extrusion, or wire drawing is repeated. In this way, it is possible to obtain an alloy bar having a diameter of 5 to 20 mm in which a 5A metal wire having a diameter of 3 to 15 μm in terms of a circle is compounded in a Cu matrix. In the case of obtaining a sample having a larger diameter, an alloy rod having a diameter of 100 mm or more can be obtained by further combining these and subjecting to HIP treatment.
これを精密カッターで厚さが６０μｍ程度になるように切り出し、精密研磨機により所定の厚さ（例えば、２５μｍ厚）に研磨する。
なお、ここに示した具体例は、好ましい製造方法の一態様であるが、用いる材料や加工条件などによって適宜変更できることは言うまでもない。
This is cut out with a precision cutter so that the thickness is about 60 μm, and is polished to a predetermined thickness (for example, 25 μm thickness) with a precision polishing machine.
Note that the specific example shown here is one mode of a preferable manufacturing method, but it is needless to say that the specific example can be appropriately changed depending on the material used, processing conditions, and the like.
こうして得られた水素透過合金膜は、その両面にＰｄ膜を成膜する。合金膜は酸化されやすいのでＰｄを含む酸化防止膜をその表面に形成するのである。本発明においては、上記の水素透過合金膜の両表面にＰｄ膜をスパッタリング法によって形成することが好ましい。
すなわち、上記水素透過合金膜をスパッタリング装置内に設置し、この水素透過合金膜を基板としてその上に、スパッタリング法を利用して、Ｐｄ膜を形成させる。合金膜をＡｒエッチングし、清浄表面とした後にＰｄ膜を形成することが望ましい。その後、積層膜を裏返し同様にエッチング後、真空を破ることなく、再びＰｄを含むターゲットを用いスパッタリングし、表面酸化のない合金膜上にＰｄ膜を形成する。
The hydrogen permeable alloy film thus obtained is formed with Pd films on both sides thereof. Since the alloy film is easily oxidized, an antioxidant film containing Pd is formed on the surface thereof. In the present invention, it is preferable to form Pd films on both surfaces of the hydrogen permeable alloy film by a sputtering method.
That is, the hydrogen permeable alloy film is placed in a sputtering apparatus, and a Pd film is formed thereon using the hydrogen permeable alloy film as a substrate by sputtering. It is desirable to form the Pd film after Ar etching the alloy film to obtain a clean surface. After that, the laminated film is etched in the same manner as the inside out, and then sputtered again using a target containing Pd without breaking the vacuum to form a Pd film on the alloy film without surface oxidation.
スパッタリング法には、希ガス（アルゴン、クリプトンなど）プラズマを高周波で発生させる高周波スパッタリング法（ＲＦスパッタリング）、直流電力で発生させる直流スパッタリング法（ＤＣスパッタリング）があるが、いずれも高効率化のため、ターゲットの裏側にマグネットを配置して希ガスプラズマをターゲット直上に集中させ、アルゴンイオンの衝突効率を上げて、低いガス圧で成膜可能としたマグネトロンスパッタ法が付加されている。
スパッタリング法の条件及び用いる装置は、特別なものが要求されるわけではない。スパッタリング法では、温度条件は、３００℃以下、例えば常温〜３００℃の間に設定される。３００℃を超えると、冷却時間が長くなってしまったり、基板の熱変形が生じたり、または基板材料と膜材料とが反応したりするので好ましくない。圧力は、希ガス（アルゴン）で０．１〜１０Ｐａとなるようにすれば良い。真空装置内に前記ターゲットを設置し、真空条件のアルゴン、クリプトンなどの希ガス雰囲気下、希ガスイオンをターゲットに照射して原料の微粒子を叩き出し、基板上に成膜する。
Sputtering methods include a high-frequency sputtering method (RF sputtering) that generates rare gas (argon, krypton, etc.) plasma at a high frequency, and a direct-current sputtering method (DC sputtering) that generates DC power, both of which are for higher efficiency. A magnetron sputtering method has been added, in which a magnet is disposed on the back side of the target to concentrate the rare gas plasma directly on the target to increase the collision efficiency of argon ions and enable film formation at a low gas pressure.
The conditions of the sputtering method and the apparatus used are not particularly required. In the sputtering method, the temperature condition is set to 300 ° C. or less, for example, between room temperature and 300 ° C. If it exceeds 300 ° C., the cooling time becomes long, the substrate is thermally deformed, or the substrate material and the film material react with each other, which is not preferable. The pressure may be 0.1 to 10 Pa with a rare gas (argon). The target is placed in a vacuum apparatus, and the target is irradiated with rare gas ions in a rare gas atmosphere such as argon or krypton under vacuum conditions, and fine particles of the raw material are ejected to form a film on the substrate.
次に、本発明の実施例を比較例とともに例示するが、本発明は、これら実施例によって何ら限定されるものではない。 Next, although the Example of this invention is illustrated with a comparative example, this invention is not limited at all by these Examples.
（実施例１）
純度９９．９％、６．４ｍｍ径×１５０ｍｍのニオブ棒を純度９９．９％のＣｕに埋め込み、８〜１０ｍｍ径に旋削加工した。これを溝ロールにより、５ｍｍとし、さらにダイス線引きで１ｍｍ径の複合線材とした。これを長さ１５０ｍｍに３００本切り出し、1インチ径の同材質（Ｃｕ）パイプに挿入し、真空中、９００℃、１ｈｒの焼鈍を行った。これを再度、溝ロールおよびダイス線引きにより１ｍｍとし、同様に３００本を複合した。これを再度、溝ロール加工で６ｍｍ径とした。これにより６ｍｍ径のＣｕマトリクスの中に５Ａ金属線が９００００本複合された棒材となり、その径は円換算でおよそ３〜１０μｍとなった。これを精密カッターで４０μｍ厚に切り出し、精密研磨機により２５μｍ厚に研磨し、５ｍｍ径、２５μｍの水素透過合金膜を得た。
断面をＳＥＭで観察し、Ｎｂ部を観察したところ、形状はほぼ楕円形であったので、長径と短径を３０個について測定し、幾何平均値に基づいて円換算直径を求めた。
この水素透過合金薄膜にスパッタリング装置（ＵＬＶＡＣ社製、ＳＢＨ２３０６ＲＤＥ）でＰｄを被覆した。スパッタ装置にＰｄターゲット、基板ホルダーに水素合金膜を取り付けた。次に、装置内を５×１０−０４Ｐａ以下まで真空排気したのち、Ａｒガス圧を１Ｐａとし、合金膜表面を１０ｍｉｎ、Ａｒエッチングし表面酸化膜を除去した後、Ｐｄターゲットに対して、ＤＣ１．０Ａのスパッタ電流を投入して、基板上にＰｄを０．０５μｍ成膜した。
表面にＰｄ被覆を行った合金膜を取り出し、これを裏返して再度基板ホルダーに取り付け、先ほどと同様の手順でＰｄターゲットにＤＣ１．０Ａのスパッタ電流を投入して、水素合金膜の裏面にもＰｄを０．０５μｍ成膜した。成膜された合金膜を大気中に取り出した。両面にＰｄが成膜された水素透過合金膜を得た。膜のＮｂとＣｕ組成をＩＣＰ分析した結果、Ｎｂが４０体積％含まれるＣｕであった。
これを、下流側に厚さ０．５ｍｍのＳＵＳ３１６製多孔質支持体を当てて、水素透過面積０．２５ｃｍ２の水素透過測定装置に取り付け、電気炉内を３００℃に加熱した。その後、水素透過合金膜に水素ガスを流し、圧力差０．１ＭＰａに設定し、透過水素流量をマスフローメーター（日本アエラ（株）製、ＦＭ−３９０）で測定した。結果を表１に示す。
Example 1
A niobium rod having a purity of 99.9% and a diameter of 6.4 mm × 150 mm was embedded in Cu having a purity of 99.9% and turned to a diameter of 8 to 10 mm. This was set to 5 mm by a groove roll, and further a composite wire having a diameter of 1 mm was formed by die drawing. 300 pieces of this were cut out to a length of 150 mm, inserted into a 1-inch diameter same material (Cu) pipe, and annealed in a vacuum at 900 ° C. for 1 hr. This was again set to 1 mm by groove rolls and die drawing, and 300 were similarly combined. This was again made into 6 mm diameter by groove roll processing. As a result, a bar material in which 90000 5A metal wires were combined in a 6 mm diameter Cu matrix was obtained, and the diameter was about 3 to 10 μm in terms of a circle. This was cut into a thickness of 40 μm with a precision cutter and polished with a precision polishing machine to a thickness of 25 μm to obtain a hydrogen permeable alloy film having a diameter of 5 mm and a thickness of 25 μm.
When the cross section was observed with an SEM and the Nb portion was observed, the shape was almost elliptical. Therefore, 30 major axes and minor axes were measured, and a circle-converted diameter was determined based on a geometric mean value.
This hydrogen permeable alloy thin film was coated with Pd by a sputtering apparatus (SBH2306RDE manufactured by ULVAC). A Pd target was attached to the sputtering device, and a hydrogen alloy film was attached to the substrate holder. Next, after evacuating the inside of the apparatus to 5 × 10 −04 Pa or less, the Ar gas pressure was set to 1 Pa, the surface of the alloy film was etched for 10 minutes, and Ar was etched to remove the surface oxide film. A sputtering current of 0.0 A was applied to form a Pd film of 0.05 μm on the substrate.
Take out the alloy film with the Pd coating on the surface, turn it over, and attach it again to the substrate holder. In the same procedure as before, apply a sputtering current of DC 1.0 A to the Pd target, and also apply Pd on the back surface of the hydrogen alloy film. Was formed to a thickness of 0.05 μm. The formed alloy film was taken out into the atmosphere. A hydrogen permeable alloy film having Pd deposited on both sides was obtained. As a result of ICP analysis of the Nb and Cu composition of the film, it was Cu containing 40% by volume of Nb.
A porous support made of SUS316 having a thickness of 0.5 mm was applied to the downstream side, and this was attached to a hydrogen permeation measuring apparatus having a hydrogen permeation area of 0.25 cm 2 , and the inside of the electric furnace was heated to 300 ° C. Thereafter, hydrogen gas was allowed to flow through the hydrogen permeable alloy membrane, the pressure difference was set to 0.1 MPa, and the permeated hydrogen flow rate was measured with a mass flow meter (FM-390, manufactured by Nippon Aera Co., Ltd.). The results are shown in Table 1.
（実施例２〜５）
Ｃｕに対するＮｂの量を変化させて、実施例１の作製方法と同様の方法により、Ｎｂ−Ｃｕ水素透過合金膜を作製した。実施例１と同様にして合金膜の表面にＰｄ膜を形成後、それを用いて透過水素流量を測定した。結果を表１に示す。なお、実施例４は、膜厚を厚くした試料を作製したものであり、表中、割れ「なし」としているが、微量のガス漏れがあった。また、実施例５は、伸線作業を途中で中止し、水素透過部の径が大きい試料を作製している（実施例４、５は、いずれも参考例である）。
(Examples 2 to 5)
An Nb—Cu hydrogen permeable alloy film was produced in the same manner as the production method of Example 1 by changing the amount of Nb relative to Cu. In the same manner as in Example 1, after forming a Pd film on the surface of the alloy film, the permeated hydrogen flow rate was measured using the Pd film. The results are shown in Table 1. In Example 4, a sample with a thick film thickness was prepared. In the table, “None” was indicated as a crack, but there was a slight amount of gas leakage. In Example 5, the wire drawing operation was stopped halfway, and a sample having a large hydrogen permeation part diameter was prepared (Examples 4 and 5 are reference examples).
（実施例６〜８）
実施例１の作製方法と同様の方法により、ＴａとＡｇ、またはＶとＡｇを用いて、Ｔａ−Ａｇ水素透過合金膜またはＶ−Ａｇ水素透過合金膜を作製した。実施例１と同様にして合金膜の表面にＰｄ膜を形成後、それを用いて透過水素流量を測定した。結果を表１に示す。
(Examples 6 to 8)
A Ta—Ag hydrogen permeable alloy film or a V—Ag hydrogen permeable alloy film was produced using Ta and Ag, or V and Ag by the same method as the production method of Example 1. In the same manner as in Example 1, after forming a Pd film on the surface of the alloy film, the permeated hydrogen flow rate was measured using the Pd film. The results are shown in Table 1.
（従来例１、２）
スパッタリング装置（ＵＬＶＡＣ社製、ＳＢＨ２３０６ＲＤＥ）を用い、内部にＰｄターゲット、Ｎｂターゲット、Ｃｕターゲットを取り付けるとともに、基板ホルダーにクラウンガラス板（５６ｍｍ×７６ｍｍ）を取り付けた。次に、装置内を５×１０−０４Ｐａ以下まで真空排気したのち、Ａｒガス圧を１Ｐａとし、先ず、Ｐｄターゲットに対して、ＤＣ１．０Ａのスパッタ電流を投入して、基板上にＰｄを０．０５μｍ成膜した。
続いて、ＮｂターゲットとＣｕターゲットに、それぞれ２．０Ａと１．０Ａのスパッタ電流を同時に投入して、Ｐｄ膜の上にＮｂ−Ｃｕ合金膜を２５μｍ成膜した。続いて、再びＰｄターゲットにＤＣ１．０Ａのスパッタ電流を投入して、Ｎｂ−Ｃｕ合金膜の上にＰｄを０．０５μｍ成膜した。
成膜された基板を大気中に取り出し、クラウンガラス板から膜を剥離して、水素透過合金膜を得た。膜のＮｂとＣｕ組成をＩＣＰ分析した結果、６３Ｎｂ−Ｃｕ、および６９Ｎｂ−Ｃｕであった。
この膜は、ＳＥＭでは分離構造が観察されず、ＮｂとＣｕが極めて微細に分散しているが、それは等方的であった。結果を表１に示す。
(Conventional examples 1 and 2)
A sputtering apparatus (ULVAC, SBH2306RDE) was used, and a Pd target, Nb target, and Cu target were attached inside, and a crown glass plate (56 mm × 76 mm) was attached to the substrate holder. Next, after evacuating the inside of the apparatus to 5 × 10−04 Pa or less, the Ar gas pressure is set to 1 Pa. First, a sputtering current of DC 1.0 A is applied to the Pd target, and Pd is reduced to 0 on the substrate. .05 μm film was formed.
Subsequently, a sputtering current of 2.0 A and 1.0 A was simultaneously applied to the Nb target and the Cu target, respectively, to form a 25 μm Nb—Cu alloy film on the Pd film. Subsequently, a sputtering current of DC 1.0 A was again applied to the Pd target to form 0.05 μm of Pd on the Nb—Cu alloy film.
The formed substrate was taken out into the atmosphere, and the film was peeled off from the crown glass plate to obtain a hydrogen permeable alloy film. As a result of ICP analysis of the Nb and Cu compositions of the film, they were 63Nb-Cu and 69Nb-Cu.
In this film, no separation structure was observed by SEM, and Nb and Cu were very finely dispersed, but this was isotropic. The results are shown in Table 1.
（比較例１〜４）
実施例１のＮｂ−Ｃｕ水素透過合金膜の製造法において、Ｎｂの含有量が異なるＮｂ−Ｃｕ水素透過合金膜を作製した。また、Ｔａの含有量が異なるＴａ−Ａｇ水素透過合金膜を作製した。実施例１と同様にして合金膜の表面にＰｄ膜を形成後、それを用いて透過水素流量を測定した。結果を表１に示す。
(Comparative Examples 1-4)
In the Nb—Cu hydrogen permeable alloy film manufacturing method of Example 1, Nb—Cu hydrogen permeable alloy films having different Nb contents were produced. In addition, Ta-Ag hydrogen permeable alloy films having different Ta contents were prepared. In the same manner as in Example 1, after forming a Pd film on the surface of the alloy film, the permeated hydrogen flow rate was measured using the Pd film. The results are shown in Table 1.
「評価」
実施例１〜３、６〜８の合金膜は、いずれも崩壊することなく、２．２〜６．０ｓｃｃｍの水素ガスを透過し、水素ガス精製・分離用として有用であることが分かった。実施例４、５（いずれも参考例）の合金膜は、膜厚が厚いか、水素透過部の直径が大きいために性能が若干低下することが分かった。
これに対し、従来例１の合金膜を用いると、ある程度十分な水素透過性能を発揮しているが、ほぼ同様のＮｂ含有量である実施例３と比べると、水素透過量が小さかった。従来例２では、割れを生じた。比較例１、３の合金膜を用いると、膜の下流では透過水素ガスをほとんど検出できなかった。比較例２、４の合金膜では、水素ガスを導入すると合金膜が崩壊し漏れが発生したことから、従来例、比較例の合金膜は、いずれも水素ガス精製・分離用として使用できないことが分かった。
"Evaluation"
The alloy films of Examples 1 to 3 and 6 to 8 were found to be useful for hydrogen gas purification / separation by allowing hydrogen gas of 2.2 to 6.0 sccm to pass through without collapsing. It was found that the performance of the alloy films of Examples 4 and 5 (both are reference examples) is slightly deteriorated because the film thickness is thick or the diameter of the hydrogen permeable part is large.
On the other hand, when the alloy film of Conventional Example 1 was used, hydrogen permeation performance sufficient to some extent was exhibited, but the hydrogen permeation amount was small as compared with Example 3 having almost the same Nb content. In Conventional Example 2, cracks occurred. When the alloy films of Comparative Examples 1 and 3 were used, almost no permeated hydrogen gas could be detected downstream of the films. In the alloy films of Comparative Examples 2 and 4, since the alloy film collapsed and leaked when hydrogen gas was introduced, the alloy films of the conventional and comparative examples cannot be used for hydrogen gas purification / separation. I understood.
１ ５Ａ金属からなる水素透過部
２ Ｃｕからなる水素不透過部
1 Hydrogen permeation part made of 5A metal 2 Hydrogen impermeable part made of Cu
Claims (7)
水素透過部（Ａ）は、水素不透過部（Ｂ）からなるマトリックス中で、膜厚方向に対して連続的に線状で連繋するが、横断面方向に対して相互に独立して微細に分散し、水素透過部（Ａ）の直径が、横断面を円に換算したとき、１５μｍ以下であって、かつ、水素透過部（Ａ）の割合は、膜全体に対して体積率基準で１５〜８０％であり、さらに、水素透過合金膜の両表面に、膜厚が０．０１〜１μｍのＰｄ膜が被覆されていることを特徴とする水素透過合金膜。 A sea-island structure formed of a hydrogen-permeable portion (A) made of a metal material that transmits hydrogen and a hydrogen-impermeable portion (B) made of a metal material that does not allow hydrogen to pass through, and is compounded while adjoining each other A hydrogen-permeable alloy film having a thickness of 1 to 50 μm ,
The hydrogen permeation part (A) is continuously connected in a linear form with respect to the film thickness direction in the matrix composed of the hydrogen non-permeation part (B). When the diameter of the hydrogen permeable part (A) is 15 μm or less when the diameter of the hydrogen permeable part (A) is converted into a circle in the cross section, the ratio of the hydrogen permeable part (A) is 15 on the volume ratio basis with respect to the whole membrane. Ri 80% der further hydrogen on both surfaces of the permeable alloy film, the hydrogen permeation alloy film, which thickness is Pd film 0.01~1μm are covered.
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