JP2008091225A - Separator for solid polymer fuel cell and its manufacturing method - Google Patents
Separator for solid polymer fuel cell and its manufacturing method Download PDFInfo
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- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
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Abstract
Description
本発明は、低温稼動が可能でメンテナンスも容易な固体高分子型燃料電池に組み込まれるステンレス鋼製セパレータに関する。 The present invention relates to a stainless steel separator incorporated in a polymer electrolyte fuel cell that can be operated at a low temperature and is easy to maintain.
固体高分子型燃料電池は、１００℃以下の低温で動作可能であり、短時間で起動する長所を備えている。しかも、各部材が固体からなる簡単な構造のため、メンテナンスが容易であるばかりでなく、振動や衝撃に曝される用途にも適用できる。さらに出力が高いため小型化に適し、燃料効率が高く低騒音であること等の長所も備えている。
１セル当りの発電量が極僅かな燃料電池から実用に供せられる電力量を取り出すには、固体高分子膜をセパレータで挟んだセルを一単位とし、多数のセルをスタックする必要がある。固体高分子膜を挟むセパレータには、導電性が良好で低い接触抵抗が要求されるため、従来から黒鉛質のセパレータが用いられている。しかし、黒鉛質セパレータは脆く、過度な振動や衝撃が加えられると割れやすい。低い加工性のため複雑形状の製品を作製する上で切削加工を余儀なくされ、脆い材質の肉厚製品とならざるを得ない。その結果、黒鉛質セパレータでは、コンパクト化の要求に十分応えることができず、また製造コストも高くなっている。
The polymer electrolyte fuel cell can operate at a low temperature of 100 ° C. or less and has an advantage of starting in a short time. Moreover, since each member is a simple structure made of a solid, not only is maintenance easy, but it can also be applied to applications where it is exposed to vibration and impact. In addition, it has advantages such as high output, suitable for downsizing, high fuel efficiency and low noise.
In order to extract the amount of electric power that can be put to practical use from a fuel cell with a very small amount of power generation per cell, it is necessary to stack a large number of cells with a unit of a solid polymer membrane sandwiched between separators. A separator that sandwiches a solid polymer film is required to have good electrical conductivity and low contact resistance, so that a graphite separator has been conventionally used. However, the graphite separator is brittle and easily breaks when excessive vibration or impact is applied. Due to its low workability, it is necessary to perform cutting work to produce a product with a complicated shape, and it must be a thick product with a brittle material. As a result, the graphite separator cannot sufficiently meet the demand for compactness, and the manufacturing cost is high.
そこで、黒鉛に代えてステンレス鋼をセパレータに使用することが検討されている（特許文献１，２）。ステンレス鋼は、高強度で延性に優れているため薄肉化が可能であり、プレス成形等の安価な加工法で目標形状に成形できる長所を備えている。また、ステンレス鋼の構成成分であるＣｒ，Ｍｏ，Ｆｅ等の酸化物，水酸化物から形成される不動態皮膜で鋼板表面が覆われ、不動態皮膜のバリア効果によって下地鋼が防食される。
不動態皮膜は、耐食性向上には有効であるが、半導体的な特性を呈し下地鋼に比較して電気伝導性に劣っている。そのため、通常の不動態皮膜が生成しているステンレス鋼をセパレータに使用すると、電極との接触抵抗が大きく、電池反応で生じた電気エネルギーがジュール熱として消費され、燃料電池の発電効率が低下する。
Then, it is examined using stainless steel for a separator instead of graphite (patent documents 1 and 2). Stainless steel can be thinned because it has high strength and excellent ductility, and has the advantage that it can be formed into a target shape by an inexpensive processing method such as press molding. Further, the surface of the steel sheet is covered with a passive film formed from oxides and hydroxides of Cr, Mo, Fe and the like, which are constituent components of stainless steel, and the base steel is protected against corrosion by the barrier effect of the passive film.
The passive film is effective in improving the corrosion resistance, but exhibits semiconducting properties and is inferior in electrical conductivity compared to the base steel. Therefore, when stainless steel with a normal passive film is used for the separator, the contact resistance with the electrode is large, the electric energy generated by the cell reaction is consumed as Joule heat, and the power generation efficiency of the fuel cell decreases. .
優れた耐食性を活用しながらステンレス鋼をセパレータに適用するためには、ステンレス鋼表面の接触抵抗を下げる必要がある。表面接触抵抗の低減策として、貴金属コーティングやステンレス鋼表面の粗面化等が検討されている。
しかしながら、高価な貴金属コーティングは、燃料電池のコストを上昇させることにもなり、経済面から燃料電池の普及に制約を加える。しかも、貴金属コーティングでは孔食の起点となるピンホールが皮膜に形成されやすいので、厳重な製品管理が必要となる。厚めっきによってピンホールの無い貴金属皮膜を形成することも可能であるが、高価な貴金属を多量に消費することになりコスト低減のネックになる。
In order to apply stainless steel to the separator while utilizing excellent corrosion resistance, it is necessary to reduce the contact resistance of the stainless steel surface. As measures for reducing the surface contact resistance, precious metal coating, stainless steel surface roughening, and the like have been studied.
However, the expensive noble metal coating also increases the cost of the fuel cell, and restricts the spread of the fuel cell from the economical aspect. Moreover, with noble metal coating, pinholes that are the starting point of pitting corrosion are likely to be formed in the film, so strict product management is required. Although it is possible to form a noble metal film having no pinholes by thick plating, a large amount of expensive noble metal is consumed, resulting in a cost reduction.
ショットブラストや酸洗、エッチングでステンレス鋼表面を粗面化し、接触抵抗を下げることも知られている。例えば特許文献３では、ショットブラストや酸洗によりセパレータの表面粗さを０.１〜１０μｍに調整すると接触抵抗が低減するとされている。また特許文献４では、セパレータの表面粗さを０.０１〜１.０μｍに調整すると接触抵抗が低下するとされている。 It is also known to roughen the surface of stainless steel by shot blasting, pickling, or etching to lower the contact resistance. For example, in Patent Document 3, the contact resistance is reduced when the surface roughness of the separator is adjusted to 0.1 to 10 μm by shot blasting or pickling. Moreover, in patent document 4, when the surface roughness of a separator is adjusted to 0.01-1.0 micrometer, it is supposed that contact resistance will fall.
特許文献５では、導電性を呈する炭化物系金属介在物やホウ化物系金属介在物を析出させたステンレス鋼の表面をショットブラスト又は酸洗することにより、前記導電性金属介在物の頭出し処理を行い、接触抵抗を低減している。しかし、ステンレス鋼に導電性介在物を形成させる工程やショットブラスト，酸洗等の工程の追加が必要となり、製造コストが高くなる。さらに、クロム炭化物の析出は耐食性の発現に必要なＣｒの消費を意味し、耐食性の低下を招き燃料電池内の過酷な環境下では十分な耐食性が確保できない。 In Patent Document 5, cueing treatment of the conductive metal inclusions is performed by shot blasting or pickling the surface of the stainless steel on which the carbide metal inclusions and boride metal inclusions exhibiting conductivity are deposited. To reduce contact resistance. However, it is necessary to add a process for forming conductive inclusions in stainless steel, a process such as shot blasting and pickling, and the manufacturing cost increases. Further, the precipitation of chromium carbide means the consumption of Cr necessary for the development of corrosion resistance, which leads to a decrease in corrosion resistance, and sufficient corrosion resistance cannot be ensured in a harsh environment within the fuel cell.
電解エッチングによるステンレス鋼表面の粗面化も検討されている。例えば、特許文献６では、電解エッチングで凹凸を付けて林立した突起をセパレータ表面に形成することにより、当該セパレータを燃料電池の電極に接触させたとき、接触面積が増加して接触抵抗を低減できることを提案している。しかし、電解粗面化処理で生じた凹凸はピッチが大きく、カーボンや金めっき層に匹敵する低接触抵抗を得るためには不十分である。電解処理であるため、設備が大掛かりになりやすいことも問題である。 Roughening of the stainless steel surface by electrolytic etching is also being studied. For example, in Patent Document 6, by forming projections that are formed with unevenness by electrolytic etching on the separator surface, the contact area can be increased and the contact resistance can be reduced when the separator is brought into contact with the electrode of the fuel cell. Has proposed. However, the unevenness produced by the electrolytic surface roughening treatment has a large pitch and is insufficient to obtain a low contact resistance comparable to that of a carbon or gold plating layer. Since it is an electrolytic treatment, it is also a problem that the equipment tends to be large.
また、特許文献７では、不動態皮膜のＣｒ／Ｆｅ原子数比をエッチング処理により１以上に調整して接触抵抗を低減化する方法も検討されている。しかしながら、単なるエッチング処理では、不動態化処理のようなＣｒ／Ｆｅ原子数比を増大させることはできず、満足できるレベルの接触抵抗は得られない。さらに接触抵抗の安定性が不十分となる。 Patent Document 7 also examines a method for reducing the contact resistance by adjusting the Cr / Fe atomic ratio of the passive film to 1 or more by etching treatment. However, a simple etching process cannot increase the Cr / Fe atomic ratio as in the passivation process, and a satisfactory level of contact resistance cannot be obtained. Furthermore, the stability of the contact resistance becomes insufficient.
ところで、本発明者等は、セパレータ用ステンレス鋼を低接触抵抗化する手段として、表面形態の調整策を検討する過程で、Ｒa，Ｒy等を指標としてセパレータの表面粗さを単に調整するだけでは不十分であり、ミクロな表面形状が接触抵抗の低減に大きな影響を与えていることを見出し、特許文献８の技術を提案している。すなわち、セパレータと接触するカーボンペーパのカーボン繊維にマッチングする表面形状にステンレス鋼の表面を改質できれば、接触抵抗を大幅に低減でき、且つ長期にわたって低接触抵抗を維持できることを見出したものである。 By the way, as a means for reducing the contact resistance of the stainless steel for the separator, the present inventors simply adjusted the surface roughness of the separator using Ra, Ry, etc. as an index in the process of adjusting the surface morphology. It is insufficient, and it has been found that a micro surface shape has a great influence on the reduction of contact resistance, and the technique of Patent Document 8 is proposed. That is, it has been found that if the surface of the stainless steel can be modified to a surface shape that matches the carbon fiber of the carbon paper in contact with the separator, the contact resistance can be greatly reduced and the low contact resistance can be maintained over a long period of time.
上記特許文献８で提案したセパレータは、カーボンペーパの繊維表面にある凹凸に対するマッチングが高く、カーボン電極との間に良好な接触状態が保たれる。そのため、低接触抵抗が達成され、燃料電池の長時間連続運転後にも低接触抵抗の増加が抑えられているので、発電効率の向上に適した燃料電池用セパレータとして極めて有用である。
上記セパレータは、その表面の微細構造を調整したものであり、本発明は、上記技術を活用しつつ、さらに表面の材質を改良して、過酷な燃料電池の環境下にあっても長期間に亘って低接触抵抗を維持することができ、長期に亘って高発電効率を維持することが可能となる固体高分子型燃料電池用セパレータを提供することを目的とする。
The separator proposed in Patent Document 8 has high matching with the unevenness on the fiber surface of the carbon paper, and maintains a good contact state with the carbon electrode. Therefore, a low contact resistance is achieved, and an increase in the low contact resistance is suppressed even after a long continuous operation of the fuel cell, which is extremely useful as a fuel cell separator suitable for improving power generation efficiency.
The separator is prepared by adjusting the fine structure of the surface, and the present invention further improves the material of the surface while utilizing the above-described technology, so that it can be used for a long time even in a harsh fuel cell environment. An object of the present invention is to provide a polymer electrolyte fuel cell separator that can maintain low contact resistance over a long period of time and can maintain high power generation efficiency over a long period of time.
本発明の固体高分子型燃料電池用セパレータは、Ｃｒ：１６〜４０質量％，Ｍｏ：１〜５質量％を含み、大きさ：０.０１〜１μｍのマイクロピットが表面全域に形成されているステンレス鋼板からなり、かつ酸化物及び／又は水酸化物として不動態皮膜中に含まれるＣｒ，Ｆｅの原子数比Ｃｒ／Ｆｅが４以上となった不動態皮膜が基材表面に形成されていることを特徴とする。
上記マイクロピットは、５μｍ×５μｍの表面領域当り２００個以上で分布しているものが好ましい。
本発明の固体高分子型燃料電池用セパレータは、Ｃｒ：１６〜４０質量％，Ｍｏ：１〜５質量％を含むステンレス鋼板を非酸化性酸液中に浸漬した後、１０〜６０質量％の硝酸水溶液中に５分以上浸漬することにより製造される。
The polymer electrolyte fuel cell separator of the present invention contains Cr: 16 to 40% by mass, Mo: 1 to 5% by mass, and micropits having a size of 0.01 to 1 μm are formed over the entire surface. A passive film made of a stainless steel plate and having a Cr / Fe atomic ratio Cr / Fe of 4 or more is formed on the substrate surface as an oxide and / or hydroxide. It is characterized by that.
The micropits are preferably distributed in a number of 200 or more per 5 μm × 5 μm surface area.
The separator for a polymer electrolyte fuel cell of the present invention has a stainless steel plate containing Cr: 16 to 40% by mass and Mo: 1 to 5% by mass, and is immersed in a non-oxidizing acid solution. It is manufactured by immersing in an aqueous nitric acid solution for 5 minutes or more.
本発明では、基材ステンレス鋼板を非酸化性酸液で処理することにより、カーボンペーパの繊維表面凹凸に対するマッチングが高いマイクロピットを形成することができ、カーボン電極との間で接触抵抗を大幅に低減できるセパレータが提供される。さらに、非酸化性酸液での処理の後の硝酸水溶液での処理により、不動態皮膜中のＣｒ濃度を大幅に増大させることができる。Ｃｒ濃度が高く接触抵抗の低い強固な不動態皮膜の形成により、過酷な燃料電池の環境下にあっても長期間に亘って低接触抵抗の維持が可能となる。その結果、長期間に亘って高い発電効率を維持できる燃料電池燃料電池用セパレータが提供される。 In the present invention, by processing the base stainless steel plate with a non-oxidizing acid solution, it is possible to form micropits with high matching to the fiber surface irregularities of the carbon paper, greatly increasing the contact resistance with the carbon electrode. A separator that can be reduced is provided. Furthermore, the Cr concentration in the passive film can be greatly increased by the treatment with the nitric acid aqueous solution after the treatment with the non-oxidizing acid solution. Formation of a strong passive film having a high Cr concentration and a low contact resistance makes it possible to maintain a low contact resistance over a long period of time even in a severe fuel cell environment. As a result, a fuel cell fuel cell separator capable of maintaining high power generation efficiency over a long period of time is provided.
本発明者等は、セパレータと電極間の接触形態が接触抵抗の低減に重要な因子となっており、さらにセパレータとしてステンレス鋼板を用いる際にはステンレス鋼表面に形成された不動態皮膜の組成が接触抵抗の劣化に影響を及ぼしているとの前提で、接触形態と不動態皮膜の組成改善策について種々検討した。
まず、接触形態の改善策について説明する。電極となるカーボンペーパを顕微鏡観察した。カーボンペーパは、直径約１０μｍのカーボン繊維を織り込んで作製されており、個々のカーボン繊維の表面にサブミクロンオーダーの凹凸が歯車状に分布している。繊維表面にある凸部と凸部の間もサブミクロンオーダーである。
In the present inventors, the contact form between the separator and the electrode is an important factor for reducing the contact resistance. Further, when a stainless steel plate is used as the separator, the composition of the passive film formed on the stainless steel surface is Based on the premise that it affects the deterioration of contact resistance, various investigations were made on measures for improving the contact form and composition of the passive film.
First, a contact form improvement measure will be described. The carbon paper used as an electrode was observed with a microscope. The carbon paper is manufactured by weaving carbon fibers having a diameter of about 10 μm, and unevenness of submicron order is distributed like a gear on the surface of each carbon fiber. The distance between the protrusions on the fiber surface is also in the submicron order.
セパレータ表面がカーボン繊維（電極）の表面形態にマッチングしやすい形態になっていると、電極面に最適状態でセパレータが接触し、接触抵抗の低下が可能になると考えられる。カーボン繊維／セパレータの接触状態のモデル図（図１）にみられるように、平滑なセパレータではカーボン繊維の突起部でカーボンペーパに接触するだけであり、接触面は非常に小さい（ａ）。 If the separator surface is in a form that easily matches the surface form of the carbon fiber (electrode), it is considered that the separator comes into contact with the electrode surface in an optimal state, and the contact resistance can be reduced. As seen in the carbon fiber / separator contact state model diagram (FIG. 1), the smooth separator only comes into contact with the carbon paper at the carbon fiber protrusion, and the contact surface is very small (a).
酸化性酸を用いた従来の酸洗やエッチングでは表面粗さを大きくすることにより、カーボンペーパとの接触点増加，ひいては接触抵抗の低減を図っている（ｂ）。粗面化はステンレス鋼表面の結晶粒界に沿って進行するエッチングの結果であり、比較的大きなピッチの凹凸が形成される。そのため、従来法で粗面化されたセパレータは、カーボンペーパとの接触点が理論的に繊維表面の凸部に限られ、接触抵抗の低減には限界がある。粗面化されたステンレス鋼表面が比較的短時間で変質し、接触抵抗が上昇することも欠点である。 In conventional pickling and etching using an oxidizing acid, the surface roughness is increased to increase the contact point with the carbon paper and to reduce the contact resistance (b). Roughening is the result of etching that proceeds along the grain boundaries on the surface of the stainless steel, forming irregularities with a relatively large pitch. For this reason, the separator roughened by the conventional method is theoretically limited in the contact point with the carbon paper to the convex portion on the fiber surface, and there is a limit in reducing the contact resistance. It is also a drawback that the roughened stainless steel surface is altered in a relatively short time and the contact resistance is increased.
これに対し、非酸化性酸を用いた表面処理では、結晶粒界の存在に関係なく結晶粒内に微細な凹凸ピット（以下、“マイクロピット”という）をステンレス鋼全面に形成できる。マイクロピットのサイズやピッチは非酸化性酸との接触条件（濃度，温度，時間等）によって調整でき、カーボン繊維の凹凸と同じオーダの大きさ（０.０１〜１μｍ）にするとカーボンペーパの繊維に対する馴染みが改善され十分に低い接触抵抗が得られる（ｃ）。 On the other hand, in the surface treatment using a non-oxidizing acid, fine uneven pits (hereinafter referred to as “micro pits”) can be formed in the entire surface of the stainless steel regardless of the presence of the grain boundaries. The size and pitch of the micropits can be adjusted according to the contact conditions (concentration, temperature, time, etc.) with the non-oxidizing acid. And the contact resistance is sufficiently low (c).
次に、不動態皮膜の組成改善策について説明する。
通常の不動態皮膜は、大気焼鈍後の酸洗仕上げ材の場合、化合物状態でＣｒ／Ｆｅ原子数比１.５〜３.０の組成を有しており、接触抵抗が大きいために実用の燃料電池用セパレータに適用することはできない。光輝焼鈍材においてもセパレータ材として使用できるような低接触抵抗は得られない。また、光輝焼鈍材，酸洗材のように通常に使用されているステンレスの仕上げでは、燃料電池に組み込んだとしても、特に酸化極側では接触抵抗が増大してしまう。
Next, measures for improving the composition of the passive film will be described.
In the case of a pickling finish after atmospheric annealing, a normal passive film has a composition of a Cr / Fe atomic ratio of 1.5 to 3.0 in a compound state, and is practical because it has a large contact resistance. It cannot be applied to a fuel cell separator. Even in the bright annealed material, such a low contact resistance that can be used as a separator material cannot be obtained. Further, in the finish of stainless steel that is normally used such as bright annealing material and pickling material, even if it is incorporated in a fuel cell, the contact resistance is increased particularly on the oxidation electrode side.
ステンレス鋼に対して、通常、耐食性を向上させるために不動態化処理が実施される。セパレータ材への不動態化処理は、接触抵抗の増大を抑制しつつ、耐食性を向上させる必要がある。接触抵抗の増大を抑制するためには、不動態皮膜中のＣｒの濃度を増加させることが有効である。
不動態皮膜中のＣｒ濃度を増加させる不動態化処理手段としては、酸素の存在する雰囲気中で加熱する方法，酸溶液中においてアノード分極する方法，硝酸等の強酸化剤中に浸漬する方法等がある。その中で、セパレータ用に適した方法としては、硝酸等の強酸化剤中に浸漬する方法が好ましい。
Stainless steel is usually passivated to improve its corrosion resistance. The passivation treatment to the separator material needs to improve the corrosion resistance while suppressing an increase in contact resistance. In order to suppress an increase in contact resistance, it is effective to increase the Cr concentration in the passive film.
Passivation treatment means for increasing the Cr concentration in the passive film include heating in an oxygen-containing atmosphere, anodic polarization in an acid solution, dipping in a strong oxidizing agent such as nitric acid, etc. There is. Among them, as a method suitable for the separator, a method of immersing in a strong oxidizing agent such as nitric acid is preferable.
酸化雰囲気中の加熱では、セパレータ（特に薄板の場合）は変形を伴いやすく、また一旦変形すると修正が困難になる。一方、酸液中でのアノード分極による不動態化処理は、設備が煩雑になるとともにコストアップとなる。
特に高Ｃｒ濃度のステンレス鋼を使用した場合、不動態皮膜中の化合物状態のＣｒ／Ｆｅ原子数比を増大させるには、強力な酸化性酸への浸漬が好ましい。酸化性酸として、硝酸，濃硫酸，熱硫酸，クロム酸，混酸等が使用できる。この中でも不動態皮膜中の化合物状態のＣｒ／Ｆｅ原子数比を４以上に増大させるためには、強力な酸化性酸である濃度１０〜６０質量％の硝酸を使用することが好ましい。
In heating in an oxidizing atmosphere, the separator (particularly in the case of a thin plate) is likely to be deformed, and once it is deformed, it becomes difficult to correct. On the other hand, the passivation treatment by anodic polarization in the acid solution makes the equipment complicated and increases the cost.
In particular, when high Cr concentration stainless steel is used, immersion in a strong oxidizing acid is preferable in order to increase the Cr / Fe atomic ratio of the compound state in the passive film. As the oxidizing acid, nitric acid, concentrated sulfuric acid, hot sulfuric acid, chromic acid, mixed acid and the like can be used. Among these, in order to increase the Cr / Fe atomic ratio in the compound state in the passive film to 4 or more, it is preferable to use nitric acid having a concentration of 10 to 60% by mass, which is a strong oxidizing acid.
本発明ステンレス鋼製セパレータをより詳しく説明すると、次の通りである。
すなわち、基材ステンレス鋼としては、Ｃｒ：１５〜４０質量％，Ｍｏ：１〜５質量％を含むフェライト系ステンレス鋼が好ましい。Ｃｒ：１５〜３５質量％，Ｍｏ：１〜３質量％のフェライト系ステンレス鋼がさらに好ましい。
Ｃｒはステンレス鋼の耐食性を確保するための主要な成分でありＣｒ含有量が多くなるほど耐食性が向上する。ｐＨが低く腐食性の強い燃料電池のセル内環境を想定すると、１５質量％以上のＣｒが必要である。Ｃｒの増量は耐食性の向上に有効であるが加工性低下の原因となるので、上限を４０質量％とする。非酸化性酸に浸漬処理することで、ステンレス鋼表面の変質部を除去することができる。
The stainless steel separator of the present invention will be described in more detail as follows.
That is, as the base stainless steel, ferritic stainless steel containing Cr: 15 to 40% by mass and Mo: 1 to 5% by mass is preferable. More preferable are ferritic stainless steels of Cr: 15 to 35 mass% and Mo: 1 to 3 mass%.
Cr is a main component for ensuring the corrosion resistance of stainless steel, and the corrosion resistance improves as the Cr content increases. Assuming an in-cell environment of a fuel cell having a low pH and strong corrosivity, 15 mass% or more of Cr is necessary. Although an increase in Cr is effective in improving corrosion resistance, it causes a decrease in workability, so the upper limit is made 40% by mass. By performing the immersion treatment in the non-oxidizing acid, the altered portion of the stainless steel surface can be removed.
Ｍｏは、Ｃｒとともに、耐食性を向上させる元素である。孔食を防ぐ作用はＭｏ単独では出現し難く、Ｃｒとの共存によって有効となる。したがって、単にＭｏを増量するのではなく、Ｃｒ含有量と関連させてＭｏ含有量を調整することが好ましい。Ｍｏは不動態皮膜の修復に有効と考えられている元素であり、強固な不動態皮膜を形成するＣｒと共存することによってステンレス鋼の耐食性が向上する。ステンレス鋼の耐食性はＣｒ＋３Ｍｏの指標で表されており、Ｍｏの増量は耐食性の向上に大きな効果がある。 Mo, together with Cr, is an element that improves corrosion resistance. The effect of preventing pitting corrosion hardly appears with Mo alone, and is effective by coexistence with Cr. Therefore, it is preferable not to simply increase the amount of Mo but to adjust the Mo content in relation to the Cr content. Mo is an element considered to be effective for repairing the passive film, and the corrosion resistance of the stainless steel is improved by coexisting with Cr forming a strong passive film. Corrosion resistance of stainless steel is expressed by an index of Cr + 3Mo, and an increase in Mo has a great effect on improving corrosion resistance.
Ｍｏはまた、カーボンペーパの繊維に対する馴染みを改善するマイクロピットの形成に必要な成分である。Ｍｏ含有量が１質量％未満では、非酸化性酸を用いた浸漬処理でマイクロピットが形成されず全面溶解になるので接触抵抗の低減に有効でない。しかし、５質量％を超える過剰量のＭｏが含まれると、ステンレス鋼が硬質化して加工性が低下する。加工性の観点からは、Ｍｏ含有量の上限は３質量％とすることが好ましい。
Ｃｒ，Ｍｏ以外の成分としては、Ｃ，Ｎ，Ｓｉ，Ｐ，Ｓ，Ｎｉ，Ｃｕ，Ｔｉ，Ｎｂ，Ａｌ，Ｖ等を含むステンレス鋼も使用可能である。
Mo is also a component necessary for forming micropits that improve the familiarity of carbon paper with fibers. When the Mo content is less than 1% by mass, the micropits are not formed by the dipping treatment using a non-oxidizing acid, and the entire surface is dissolved, so that it is not effective in reducing contact resistance. However, if an excessive amount of Mo exceeding 5% by mass is included, the stainless steel becomes hard and the workability deteriorates. From the viewpoint of workability, the upper limit of the Mo content is preferably 3% by mass.
As components other than Cr and Mo, stainless steel containing C, N, Si, P, S, Ni, Cu, Ti, Nb, Al, V, and the like can be used.
Ｃ，Ｎは、ステンレス鋼の加工性，低温靭性に悪影響を及ぼすので可能な限り低減すべきであり、好ましくは共に０.０２質量％以下とする。Ｓｉは、ステンレス鋼を硬質化して加工性を低下させるので、好ましくは０.５質量％以下とする。Ｐは、セパレータが曝される燃料電池の内部環境における耐食性向上に有効な成分であるが、過剰添加は加工性に悪影響を与えるので、添加する場合には０.０３〜０.０８質量％の範囲でＰ含有量を選定する。Ｓは、耐食性に有害な成分であるので可能な限りの低減が必要であり、好ましくは０.００５質量％以下に規制する。 C and N have an adverse effect on the workability and low-temperature toughness of stainless steel, so they should be reduced as much as possible, and preferably both are 0.02% by mass or less. Since Si hardens stainless steel and lowers workability, it is preferably 0.5% by mass or less. P is an effective component for improving the corrosion resistance in the internal environment of the fuel cell to which the separator is exposed. However, excessive addition has an adverse effect on processability, so that when added, the content of 0.03 to 0.08 mass%. Select P content by range. Since S is a component harmful to corrosion resistance, it needs to be reduced as much as possible, and is preferably regulated to 0.005% by mass or less.
Ｎｉ，Ｃｕは、溶出しやすい元素であるので多量含有を避け、好ましくは上限をＮｉ：０.５質量％，Ｃｕ：０.８質量％とする。なかでも、溶出したＮｉイオンが触媒層に到達すると、触媒が被毒し電池性能が低下する。他方、少量の添加は酸性雰囲気での耐全面腐食性を改善し、フェライト系ステンレス鋼の低温靭性を向上させる作用も呈するので、添加する場合にはＮｉ：０.１５〜０.３５質量％，Ｃｕ：０.２０〜０.５０質量％の範囲でＮｉ，Ｃｕ含有量を選定することが好ましい。 Ni and Cu are elements that are easily eluted, so that they are not contained in large amounts, and the upper limit is preferably set to Ni: 0.5% by mass and Cu: 0.8% by mass. Among these, when the eluted Ni ions reach the catalyst layer, the catalyst is poisoned and the battery performance is deteriorated. On the other hand, the addition of a small amount improves the overall corrosion resistance in an acidic atmosphere and also improves the low temperature toughness of the ferritic stainless steel, so when added, Ni: 0.15 to 0.35 mass%, Cu: It is preferable to select Ni and Cu contents in the range of 0.20 to 0.50 mass%.
その他、鋼中のＣ，Ｎを固定し加工性を改善する作用を呈するＴｉ，Ｎｂを、必要に応じて添加しても良い。Ｔｉ，Ｎｂを添加する場合には共に０.０３〜０.２５質量％の範囲で調整する。Ｎの固定にＡｌを使用する場合、０.０４〜０.２５質量％の範囲でＡｌ含有量を選定する。Ｖは、燃料電池の内部環境における耐食性を改善する作用があるので、必要に応じて０.２〜１.０質量％の範囲で添加する。さらに特性を大きく変化させない限り、他の合金成分を添加することも可能である。 In addition, Ti and Nb that fix C and N in steel and improve workability may be added as necessary. When adding Ti and Nb, both are adjusted in the range of 0.03 to 0.25% by mass. When Al is used for fixing N, the Al content is selected in the range of 0.04 to 0.25% by mass. V has the effect of improving the corrosion resistance in the internal environment of the fuel cell, so V is added in the range of 0.2 to 1.0% by mass as necessary. Further, other alloy components can be added as long as the characteristics are not greatly changed.
上記のように所定組成に調整されたＭｏ含有フェライト系ステンレス鋼を非酸化性酸液に浸漬すると、鋼板表面全域に多数のマイクロピットが形成される。非酸化性酸液を用いた浸漬処理では、マイクロピットの大きさが１μｍ以下（好ましくは、０.５μｍ以下）となるようにステンレス鋼の種類に応じて酸の種類，濃度，温度，浸漬時間等の浸漬条件を調整する。たとえば、３０Ｃｒ‐２Ｍｏ鋼では、濃度：１０〜２０質量％，液温：４０〜６０℃の塩酸浴に０.５〜１０分浸漬する条件が採用される。硫酸を使用する場合には、濃度：１０〜２０質量％，液温：５０〜８０℃の硫酸浴に０.５〜２０分浸漬する。 When the Mo-containing ferritic stainless steel adjusted to a predetermined composition as described above is immersed in a non-oxidizing acid solution, a large number of micropits are formed over the entire surface of the steel sheet. In the immersion treatment using a non-oxidizing acid solution, the acid type, concentration, temperature, and immersion time depending on the type of stainless steel so that the micropit size is 1 μm or less (preferably 0.5 μm or less). Adjust soaking conditions. For example, in 30Cr-2Mo steel, conditions of immersion in a hydrochloric acid bath having a concentration of 10 to 20% by mass and a liquid temperature of 40 to 60 ° C. for 0.5 to 10 minutes are employed. When sulfuric acid is used, it is immersed in a sulfuric acid bath having a concentration of 10 to 20% by mass and a liquid temperature of 50 to 80 ° C. for 0.5 to 20 minutes.
非酸化性酸液にステンレス鋼を浸漬すると、鋼板表面の溶解が始まる。Ｍｏを含む高耐食フェライト系ステンレス鋼の場合、全面溶解ではなく部分的な孔食状の溶解が生じマイクロピットが形成される。このときの溶解は、結晶粒界の分布形態とほとんど無関係で結晶粒内にも発生し、鋼板表面にほぼ均一な密度でマイクロピットが分布する。マイクロピットはサブミクロンオーダーまで成長するが、その間に他の表面域でも多数のピットが発生し、結果として表面全域を覆う分布でマイクロピットが形成される。マイクロピットの増加に応じて接触抵抗が低減し、ステンレス鋼表面全域にマイクロピットが形成された時点で最も低い接触抵抗が得られる。 When stainless steel is immersed in a non-oxidizing acid solution, dissolution of the steel sheet surface begins. In the case of high corrosion resistant ferritic stainless steel containing Mo, partial pitting corrosion occurs instead of melting the entire surface, and micropits are formed. The melting at this time is almost independent of the distribution form of the crystal grain boundaries and also occurs in the crystal grains, and micropits are distributed at a substantially uniform density on the steel plate surface. The micropits grow to the submicron order, but during that time, a large number of pits are generated in other surface areas, and as a result, the micropits are formed in a distribution covering the entire surface area. The contact resistance decreases as the number of micropits increases, and the lowest contact resistance is obtained when the micropits are formed over the entire surface of the stainless steel.
浸漬処理を更に継続すると、マイクロピットが相互に連絡・一体化し、通常のエッチングで粗面化された鋼表面にみられる凹凸と同様な表面形態になり、接触抵抗が増加する。
マイクロピットは、大きさが０.０１〜１μｍ（好ましくは０.０５〜１μｍ，更に好ましくは０.１〜０.５μｍ）の範囲に調整されている。大きさ：０.０１〜１μｍは、カーボンペーパの繊維表面の凹凸サイズと同じオーダにあり、カーボンペーパに対するセパレータの馴染みを向上させる。大きさが０.０１μｍ以下のピットではカーボンペーパの繊維表面に対する接触面積の増加は期待できず、逆に１μｍを超える大きさではカーボン繊維表面とマッチングしにくくなり接触面積が却って低減する。
When the dipping process is further continued, the micropits are connected and integrated with each other, resulting in a surface form similar to the unevenness seen on the steel surface roughened by normal etching, and the contact resistance increases.
The micropits have a size adjusted to a range of 0.01 to 1 μm (preferably 0.05 to 1 μm, more preferably 0.1 to 0.5 μm). The size: 0.01 to 1 μm is in the same order as the uneven size of the fiber surface of the carbon paper, and improves the familiarity of the separator to the carbon paper. If the size of the pit is 0.01 μm or less, an increase in the contact area of the carbon paper with the fiber surface cannot be expected. Conversely, if the size exceeds 1 μm, it is difficult to match the carbon fiber surface and the contact area is reduced.
マイクロピットは、５μｍ×５μｍの表面領域当り２００個以上（好ましくは、５００個以上）の密度でセパレータ表面に分布していることが好ましい。２００個未満の分布密度では平滑面が占める割合が多くなり、十分な接触抵抗低減効果が得られず、燃料電池セル内環境下での接触抵抗が増大する。
また、タッピングモード原子間力顕微鏡（ＡＦＭ）で測定した５μｍ×５μｍの表面領域における平均粗さがＲa≧０.０１μｍ(好ましくは、Ｒa≧０.０２μｍ)であり、ＡＦＭデータを用いて計算した二次元等方性パワースペクトル密度（2D isotropic PSD）において波長０.２μｍと波長５μｍのパワースペクトル密度比（０.２／５：ＰＳＤ）が０.１以上（好ましくは、０.５以上）である。
The micropits are preferably distributed on the separator surface at a density of 200 or more (preferably 500 or more) per surface area of 5 μm × 5 μm. When the distribution density is less than 200, the smooth surface occupies a large proportion, so that a sufficient contact resistance reduction effect cannot be obtained, and the contact resistance in the environment inside the fuel cell increases.
Further, the average roughness in the surface area of 5 μm × 5 μm measured with a tapping mode atomic force microscope (AFM) is Ra ≧ 0.01 μm (preferably Ra ≧ 0.02 μm), and calculation was performed using AFM data. In the two-dimensional isotropic power spectral density (2D isotropic PSD), the power spectral density ratio (0.2 / 5: PSD) between the wavelength of 0.2 μm and the wavelength of 5 μm is 0.1 or more (preferably 0.5 or more). is there.
二次元等方性パワースペクトル密度は、表面形態の評価に際しＲa，Ｒyのような粗さの指標でなく、凹凸の山と山との間隔といった凹凸のピッチを表現するのに適している。セパレータの好ましい表面形態は、カーボン繊維表面の凹凸にマッチングするサブミクロンオーダーの凹凸が存在することである。低接触抵抗を示すセパレータでは、サブミクロンオーダーのパワースペクトル密度とミクロンオーダーのパワースペクトル密度の比(サブミクロンオーダーのパワースペクトル密度／ミクロンオーダーのパワースペクトル密度)が大きくなる必要がある。たとえば、サブミクロンオーダーとして波長０.２μｍのパワースペクトル密度，ミクロンオーダーとして波長５μｍのパワースペクトル密度をとったとき、その比（０.２／５：ＰＳＤ）が０.１以上（好ましくは、０.５以上）で接触抵抗の低減が可能になる。 The two-dimensional isotropic power spectral density is suitable for expressing the pitch of the projections and depressions such as the interval between the peaks and depressions of the projections and depressions instead of the roughness index such as Ra and Ry when evaluating the surface morphology. A preferable surface form of the separator is that there are unevenness of submicron order matching the unevenness of the carbon fiber surface. In a separator exhibiting low contact resistance, the ratio of the power spectral density in the submicron order to the power spectral density in the micron order (submicron order power spectral density / micron order power spectral density) needs to be increased. For example, when a power spectral density of a wavelength of 0.2 μm is taken as a submicron order and a power spectral density of a wavelength of 5 μm is taken as a micron order, the ratio (0.2 / 5: PSD) is 0.1 or more (preferably, 0 .5 or more), the contact resistance can be reduced.
セパレータ表面に存在するマイクロピットの分布密度は、表面積の増加量によっても特定できる。マイクロピットによりセパレータの実効表面積は増加するが、実効表面積の増加割合は、鋼板表面の投影面積に対する比率として定量化できる。すなわち、ＡＦＭ測定で得られた実効表面積をＳ1，投影面積をＳ0とすると、表面積増加率ΔＳ（％）は｛（Ｓ1／Ｓ0）−１｝×１００として算出される。
大きな表面積増加率ΔＳはセパレータ表面に多数のマイクロピットがあることを意味し、ΔＳ≧１５％(好ましくは、ΔＳ≧２０％)でカーボンペーパの繊維表面に対するセパレータの接触状態が改善され、接触抵抗の低減効果が顕著になる。
The distribution density of micropits existing on the separator surface can also be specified by the amount of increase in surface area. Although the effective surface area of the separator is increased by micropits, the increase rate of the effective surface area can be quantified as a ratio to the projected area of the steel sheet surface. That is, assuming that the effective surface area obtained by AFM measurement is S 1 and the projected area is S 0 , the surface area increase rate ΔS (%) is calculated as {(S 1 / S 0 ) −1} × 100.
A large surface area increase rate ΔS means that there are a large number of micropits on the separator surface, and ΔS ≧ 15% (preferably ΔS ≧ 20%) improves the contact state of the separator to the fiber surface of the carbon paper, and the contact resistance The reduction effect becomes remarkable.
表面積増加率ΔＳ≧１５％に併せて、先端径５μｍのプローブで測定した表面粗さがＲa≦０.５μｍであることが好ましい。先端径５μｍのプローブは、ミクロンオーダーの凹凸が測定対象であり、Ｒa≦０.５μｍの測定値はカーボン繊維との接触に寄与しない凹凸が少ないことを意味する。逆にＲa＞０.５μｍであれば、増加した表面がカーボン繊維との接触に働かないばかりでなく、不必要な表面積の増加に伴って金属製セパレータから金属イオンとなって溶出する量が多くなり、燃料電池の性能を低下させる。 In addition to the surface area increase rate ΔS ≧ 15%, the surface roughness measured with a probe having a tip diameter of 5 μm is preferably Ra ≦ 0.5 μm. The probe with a tip diameter of 5 μm is subject to measurement of micron-order irregularities, and a measured value of Ra ≦ 0.5 μm means that there are few irregularities that do not contribute to contact with the carbon fiber. On the contrary, if Ra> 0.5 μm, not only the increased surface does not work for contact with the carbon fiber, but also the amount of metal ions eluted from the metal separator as the surface area increases unnecessarily. This degrades the performance of the fuel cell.
上記のように非酸化性酸液への浸漬により表面に所定のマイクロピットが形成されたフェライト系ステンレス鋼を酸化性酸である硝酸水溶液に浸漬してＣｒ濃度の高い不動態皮膜を形成する。
不動態皮膜中の化合物状態のＣｒ／Ｆｅ原子数比で不動態皮膜の健全性が示され、Ｃｒ／Ｆｅ比が大きいほどバリアー効果が高く、従って不動態皮膜の増大による接触抵抗増大が抑制される。特に燃料電池内の腐食性の強い環境下では、Ｃｒ／Ｆｅ比が４以上でないと不動態皮膜の成長が起こりやすく、結果として接触抵抗が増大してしまう。
As described above, a ferritic stainless steel having predetermined micropits formed on the surface by dipping in a non-oxidizing acid solution is dipped in an aqueous nitric acid solution that is an oxidizing acid to form a passive film having a high Cr concentration.
The soundness of the passive film is shown by the Cr / Fe atomic ratio of the compound state in the passive film, and the higher the Cr / Fe ratio, the higher the barrier effect, thus suppressing the increase in contact resistance due to the increase of the passive film. The In particular, in a highly corrosive environment in the fuel cell, if the Cr / Fe ratio is not 4 or more, the passive film tends to grow, resulting in an increase in contact resistance.
硝酸は、不動態皮膜に酸素を供給するための強力な酸化剤であり、濃度が高いほど、また浸漬時間が長いほど不動態化が促進される。Ｃｒ／Ｆｅ比４以上の不動態皮膜は、Ｃｒ含有量１５〜４０質量％のステンレス鋼を、１０〜６０質量％の硝酸水溶液中に５分以上浸漬することにより形成される。硝酸濃度が１０質量％に満たなかったり、浸漬時間が短過ぎたりするとＣｒ濃化が進行しない。
上記不動態化の際、Ｃｒ酸化物に比べ、バリアー性の弱いＦｅ酸化物が溶解し、結果としてＣｒ／Ｆｅ比が大きくなることと、Ｆｅ酸化物の溶解に伴い不動態皮膜は実質的に薄くなるため、接触抵抗は低減化する。
大気中酸化では、Ｆｅ酸化物の溶解がないため、Ｃｒ／Ｆｅ比は硝酸浸漬の場合のような大きな値とはならない。
Nitric acid is a strong oxidizing agent for supplying oxygen to the passive film, and the higher the concentration and the longer the immersion time, the more the passivation is promoted. A passive film having a Cr / Fe ratio of 4 or more is formed by immersing stainless steel having a Cr content of 15 to 40% by mass in an aqueous nitric acid solution having a content of 10 to 60% by mass for 5 minutes or more. If the nitric acid concentration is less than 10% by mass or the immersion time is too short, the Cr concentration does not proceed.
At the time of the passivation, Fe oxide having a weak barrier property is dissolved as compared with Cr oxide, and as a result, the Cr / Fe ratio is increased, and the passivation film is substantially accompanied by dissolution of Fe oxide. Since it becomes thinner, the contact resistance is reduced.
In the atmospheric oxidation, since the Fe oxide does not dissolve, the Cr / Fe ratio does not become a large value as in the case of nitric acid immersion.
実施例１：
３０Ｃｒ‐２Ｍｏ，２２Ｃｒ‐１.２Ｍｏ，１８Ｃｒ‐２Ｍｏ，１８Ｃｒの合計４種類のフェライト系ステンレス鋼をセパレータ素材に使用し、非酸化性酸浸漬がステンレス鋼の表面形態に及ぼす影響を調査した。何れのステンレス鋼に対しても非酸化性酸浸漬に先立って、濃度：５質量％，液温：６０℃のオルトケイ酸ソーダ溶液に１０秒間浸漬する脱脂処理を施した。
濃度：１０質量％，液温：５０℃の塩酸溶液を用いて脱脂処理後のステンレス鋼を浸漬処理した。非酸化性酸浸漬処理後、不動態化皮膜を形成するために、濃度：３０質量％，液温：５０℃の硝酸中に１０分間浸漬する処理を施し、その後直ちに水洗し、ドライヤーで乾燥させた。なお、塩酸溶液浸漬処理では、接触抵抗に及ぼす表面形態の影響を調査するため浸漬時間を種々変化させた。
Example 1:
A total of four types of ferritic stainless steels of 30Cr-2Mo, 22Cr-1.2Mo, 18Cr-2Mo, and 18Cr were used as separator materials, and the effect of non-oxidizing acid immersion on the surface morphology of stainless steel was investigated. Prior to the immersion in the non-oxidizing acid, any stainless steel was subjected to a degreasing treatment in which it was immersed in a sodium orthosilicate solution having a concentration of 5% by mass and a liquid temperature of 60 ° C. for 10 seconds.
The stainless steel after the degreasing treatment was immersed using a hydrochloric acid solution having a concentration of 10% by mass and a liquid temperature of 50 ° C. After the non-oxidizing acid dipping treatment, in order to form a passivated film, a treatment of dipping in nitric acid at a concentration of 30% by mass and a liquid temperature of 50 ° C. is performed for 10 minutes, and then immediately washed with water and dried with a dryer. It was. In the hydrochloric acid solution immersion treatment, the immersion time was variously changed in order to investigate the influence of the surface form on the contact resistance.
非酸化性酸浸漬処理とその後の酸化性酸浸漬処理が施されたステンレス鋼から試験片を切り出し、初期接触抵抗及び湿潤試験後の接触抵抗を測定した。初期接触抵抗は、試験片を室内に７２時間放置した後、試験片に対し燃料電池における拡散層を形成するカーボンペーパを荷重：１ＭＰａで接触させ、ステンレス鋼／カーボンペーパ間の接触抵抗を測定した。湿潤試験後の接触抵抗は、燃料電池の内部環境を模擬した温度：７０℃，湿度：９８％RHの湿潤環境下に７２時間放置した試験片に同様にカーボンペーパを荷重：１ＭＰａで接触させ、接触抵抗を測定した。 A test piece was cut out from the stainless steel subjected to the non-oxidizing acid immersion treatment and the subsequent oxidizing acid immersion treatment, and the initial contact resistance and the contact resistance after the wet test were measured. The initial contact resistance was determined by measuring the contact resistance between stainless steel and carbon paper after leaving the test piece in the room for 72 hours and then contacting the test piece with carbon paper forming a diffusion layer in the fuel cell at a load of 1 MPa. . The contact resistance after the wet test was determined by bringing a carbon paper into contact with a test piece left for 72 hours in a wet environment at a temperature of 70 ° C. and a humidity of 98% RH simulating the internal environment of the fuel cell at a load of 1 MPa. Contact resistance was measured.
非酸化性酸浸漬処理していないステンレス鋼の接触抵抗は、３０Ｃｒ‐２Ｍｏで４０ｍΩ・ｃｍ2，２２Ｃｒ‐１.２Ｍｏで２１０ｍΩ・ｃｍ2，１８Ｃｒ‐２Ｍｏで５０ｍΩ・ｃｍ2，１８Ｃｒで５５０ｍΩ・ｃｍ2であったが、何れも非酸化性酸浸漬によって接触抵抗が大幅に低下した。また、低位の接触抵抗が得られる浸漬時間は鋼種によって異なっていた。 Contact resistance stainless steel which is not a non-oxidizing acid immersion treatment, 40mΩ · cm 2 in 30Cr-2Mo, 210mΩ · cm 2 in 22Cr-1.2Mo, 18Cr-2Mo 50mΩ · cm 2 in, 550mΩ · with 18Cr cm In all cases, the contact resistance was significantly reduced by immersion in the non-oxidizing acid. Moreover, the immersion time for obtaining a low contact resistance varied depending on the steel type.
非酸化性酸浸漬処理された各ステンレス鋼について、FE-SEMで撮影した表面画像からマイクロピットをカウントし、マイクロピットの分布密度を５μｍ×５μｍの表面領域当たりの個数として求めた。
マイクロピットが５μｍ×５μｍの表面領域当り２００個以上になると、表１にみられるように非酸化性酸浸漬で低接触抵抗を示し、低接触抵抗が湿潤試験７２時間後も維持されている。他方、２００個未満の分布密度では、非酸化性酸浸漬で接触抵抗が十分に低減せず、湿潤試験後にも接触抵抗が大幅に増加した。
For each stainless steel subjected to the non-oxidizing acid immersion treatment, micropits were counted from the surface image photographed by FE-SEM, and the distribution density of micropits was determined as the number per 5 μm × 5 μm surface area.
When the number of micropits is 200 or more per surface area of 5 μm × 5 μm, as shown in Table 1, low contact resistance is exhibited by immersion in a non-oxidizing acid, and the low contact resistance is maintained even after 72 hours of the wet test. On the other hand, with a distribution density of less than 200, the contact resistance was not sufficiently reduced by immersion in a non-oxidizing acid, and the contact resistance was significantly increased even after the wet test.
次いで、３０Ｃｒ‐２Ｍｏを例にとって、１０質量％の塩酸（５０℃）を用いた非酸化性酸浸漬処理での浸漬時間を変化させ、浸漬時間が接触抵抗，表面粗さに及ぼす影響を調査した。なお、表面粗さは、先端径：５μｍの触針式表面粗さ計で測定した。試料はいずれも、非酸化性酸浸漬処理の後、濃度：３０質量％，液温：５０℃の硝酸中に１０分間浸漬する酸化性酸浸漬処理を施している。
表２の測定結果にみられるように、表面粗さは非酸化性酸浸漬処理の前後や浸漬時間に関係なくＲa：０.１６〜０.１７μｍの範囲にあったが、非酸化性酸浸漬処理によって接触抵抗が大幅に低減していた。処理時間５分では未処理と同じＲaを示しているが、表面積増加率は４５.６％と非常に大きくなっていた。表２の結果は、表面粗さＲaの調整で接触抵抗を低減する従来法からは窺い知れないことを意味する。
Next, taking 30Cr-2Mo as an example, the effect of immersion time on contact resistance and surface roughness was investigated by changing the immersion time in non-oxidizing acid immersion treatment using 10% by mass hydrochloric acid (50 ° C.). . The surface roughness was measured with a stylus type surface roughness meter having a tip diameter of 5 μm. All samples were subjected to an oxidizing acid immersion treatment in which the sample was immersed in nitric acid having a concentration of 30% by mass and a liquid temperature of 50 ° C. for 10 minutes after the non-oxidizing acid immersion treatment.
As can be seen from the measurement results in Table 2, the surface roughness was in the range of Ra: 0.16 to 0.17 μm regardless of before and after the non-oxidizing acid dipping treatment and the dipping time. The contact resistance was greatly reduced by the treatment. The treatment time of 5 minutes showed the same Ra as that of the untreated, but the surface area increase rate was 45.6% which was very large. The results in Table 2 mean that the conventional method of reducing the contact resistance by adjusting the surface roughness Ra cannot be ignored.
接触抵抗の低減が単純な表面粗さＲaで説明できないことから、非酸化性酸浸漬処理されたステンレス鋼の表面形態をより詳細に調査するため、走査型プローブ顕微鏡(Nanoscope IIIa型，D3100：デジタル・インスツルメント社製)，タッピングモード原子間力顕微鏡(AFM)を用い、スキャンサイズ：５μｍ×５μｍでステンレス鋼表面を観察した。AFMで測定した微小領域の表面粗さを表３に示す。
予めカーボンペーパの繊維表面もAFM分析にかけ、表面形状を求めた。カーボンペーパには、図２の断面プロファイルにみられるようにサブミクロンオーダーの凹凸があり、凹凸のピッチ(波長)はほぼ０.２μｍであった。
Since the reduction of contact resistance cannot be explained by simple surface roughness Ra, a scanning probe microscope (Nanoscope IIIa type, D3100: Digital) is used to investigate the surface morphology of stainless steel treated with non-oxidizing acid in more detail.・ The surface of stainless steel was observed at a scan size of 5 μm × 5 μm using a tapping mode atomic force microscope (AFM). Table 3 shows the surface roughness of the micro area measured by AFM.
The surface of the carbon paper fiber surface was also subjected to AFM analysis in advance. The carbon paper had irregularities on the order of submicrons as seen in the cross-sectional profile in FIG. 2, and the pitch (wavelength) of the irregularities was approximately 0.2 μm.
次いで、測定により得られたAFMデータを用い二次元等方性パワースペクトル密度によりステンレス鋼の表面形状を評価した。二次元等方性パワースペクトル密度による表面形態の評価は、Ｒaがほぼ同じであってもステンレス鋼表面にある凹凸のスケールに違いがある場合に有効である。
二次元等方性パワースペクトル密度を計算してみると、塩酸浸漬したステンレス鋼は、未処理ステンレス鋼に比較して短波長，長波長共にスペクトル密度が増大している。カーボンペーパの繊維表面の波長が約０.２μｍであり、これに対応した波長０.２μｍの比率が大きな表面形態は５分の浸漬処理で得られ、６０分の浸漬処理では波長０.２μｍの占める割合が低下していた。波長０.２μｍの占める割合に呼応し、浸漬処理６０分に比較して浸漬処理５分で大幅に低い接触抵抗が得られた。この結果は、単なる表面粗さＲaではなく、短波長の比率を大きくした表面形態が接触抵抗の低減に有効であることを示している。
Next, the surface shape of the stainless steel was evaluated by two-dimensional isotropic power spectral density using the AFM data obtained by the measurement. The evaluation of the surface morphology based on the two-dimensional isotropic power spectral density is effective when there is a difference in the unevenness scale on the stainless steel surface even if Ra is substantially the same.
When the two-dimensional isotropic power spectral density is calculated, the spectral density of stainless steel immersed in hydrochloric acid is increased in both short wavelength and long wavelength compared to untreated stainless steel. The wavelength of the surface of the fiber of carbon paper is about 0.2 μm, and a corresponding surface form with a large ratio of the wavelength of 0.2 μm can be obtained by the immersion treatment for 5 minutes, and the wavelength of 0.2 μm is obtained by the immersion treatment for 60 minutes. The proportion occupied was decreasing. Corresponding to the ratio of the wavelength of 0.2 μm, a significantly lower contact resistance was obtained in 5 minutes of immersion treatment compared to 60 minutes of immersion treatment. This result shows that a surface form with a larger ratio of short wavelengths is effective in reducing the contact resistance, not just the surface roughness Ra.
塩酸に５分浸漬処理したステンレス鋼の表面を、先端径：５μｍの触針式表面粗さ計で測定してもＲa：０.１６μｍと従来の酸洗材と大差ないが、AFM像の断面解析で求められる断面プロファイルではカーボンペーパの繊維表面にある凹凸とほぼ同じピッチの凹凸が形成されていることが判る。その結果、図１(c)で説明した良好なマッチング性でカーボンペーパにステンレス鋼が接触し、接触抵抗が４ｍΩ・ｃｍ2と低い値を示したものと考えられる。 Even if the surface of stainless steel immersed in hydrochloric acid for 5 minutes is measured with a stylus type surface roughness meter with a tip diameter of 5 μm, Ra is 0.16 μm, which is not much different from conventional pickling materials, but the cross section of the AFM image It can be seen from the cross-sectional profile obtained by the analysis that irregularities having substantially the same pitch as the irregularities on the fiber surface of the carbon paper are formed. As a result, it is considered that the stainless steel was in contact with the carbon paper with the good matching described with reference to FIG. 1C, and the contact resistance was as low as 4 mΩ · cm 2 .
次いで、非酸化性酸浸漬処理及びその後の酸化性酸浸漬処理を施したステンレス鋼製セパレータを燃料電池の燃料極側，酸化極側に組み込み、燃料電池を１００時間連続運転し、接触抵抗の増加，出力変化を調査した。
表４の調査結果にみられるように、No.１〜３のステンレス鋼製セパレータを組み込んだ燃料電池では、１００時間の連続運転後も出力低下がなく、接触抵抗の増加量も５ｍΩ・ｃｍ2以下に抑えられていた。接触抵抗の変化を表面積増加率で整理すると、表面積増加率：１５％以上の表面形態に調整されたセパレータは、１００時間の連続運転後にも低接触抵抗を維持していた。
Next, a stainless steel separator subjected to non-oxidizing acid immersion treatment and subsequent oxidizing acid immersion treatment is incorporated into the fuel electrode side and the oxidation electrode side of the fuel cell, and the fuel cell is continuously operated for 100 hours to increase contact resistance. The output change was investigated.
As can be seen from the results of the investigation in Table 4, the fuel cell incorporating the stainless steel separators No. 1 to 3 has no decrease in output even after 100 hours of continuous operation, and the increase in contact resistance is 5 mΩ · cm 2. It was suppressed to the following. When the change in the contact resistance is organized by the surface area increase rate, the separator adjusted to a surface form with a surface area increase rate of 15% or more maintained a low contact resistance even after 100 hours of continuous operation.
他方、マイクロピットを形成していない１８Ｃｒステンレス鋼製セパレータでは、接触抵抗の増加量が大きく出力が低下した。また、表面積増加率が１５％に達しないステンレス鋼製セパレータでは、連続運転後に接触抵抗が大幅に上昇し、それに伴って出力も低下した。
この対比からステンレス鋼表面にマイクロピットを形成することにより長期間にわたって低接触抵抗，高出力が維持され、燃料電池に適した特性が付与されていることが判る。また、表面積増加率を１５％以上とした表面形態でＲaを０.５μｍ以下に抑えることによっても、同様に低接触抵抗の維持，燃料電池出力の低下防止に有効なステンレス鋼製セパレータとなる。
On the other hand, in the 18Cr stainless steel separator in which the micropits are not formed, the increase in the contact resistance is large and the output is reduced. Moreover, in the stainless steel separator whose surface area increase rate does not reach 15%, the contact resistance significantly increased after continuous operation, and the output also decreased accordingly.
From this comparison, it can be seen that by forming micropits on the surface of stainless steel, low contact resistance and high output are maintained over a long period of time, and characteristics suitable for fuel cells are imparted. In addition, by suppressing the surface roughness Ra to 0.5 μm or less with a surface form with a surface area increase rate of 15% or more, a stainless steel separator that is also effective in maintaining low contact resistance and preventing fuel cell output from decreasing is obtained.
実施例２：
３０Ｃｒ‐２Ｍｏのフェライト系ステンレス鋼をセパレータ素材に使用し、非酸化性酸浸漬後の酸化性酸浸漬処理が不動態皮膜中のＣｒ／Ｆｅ原子数比及び接触抵抗に及ぼす影響を調査した。非酸化性酸浸漬に先立って、濃度：５質量％，液温：６０℃のオルトケイ酸ソーダ溶液中で電流密度５Ａ／ｄｍ2で１０秒間陰極電解脱脂処理を施した。非酸化性酸浸漬処理は、濃度：１０質量％，液温：５０℃の塩酸溶液を用いて上記脱脂処理後のステンレス鋼を５分間浸漬する処理で行った。
酸化性酸への浸漬処理による不動態化処理は、上記非酸化性酸浸漬処理に引続き、濃度：３０質量％，液温：５０℃の硝酸中に１０〜１２０分間浸漬した。浸漬処理後、直ちに水洗し、ドライヤーで乾燥させた。
Example 2:
30Cr-2Mo ferritic stainless steel was used as a separator material, and the effect of oxidizing acid immersion treatment after non-oxidizing acid immersion on the Cr / Fe atomic ratio and contact resistance in the passive film was investigated. Prior to the non-oxidizing acid immersion, cathodic electrolytic degreasing treatment was performed for 10 seconds at a current density of 5 A / dm 2 in a sodium orthosilicate solution having a concentration of 5 mass% and a liquid temperature of 60 ° C. The non-oxidizing acid dipping treatment was performed by dipping the degreased stainless steel for 5 minutes using a hydrochloric acid solution having a concentration of 10% by mass and a liquid temperature of 50 ° C.
Passivation treatment by immersion treatment in an oxidizing acid was immersed in nitric acid having a concentration of 30% by mass and a liquid temperature of 50 ° C. for 10 to 120 minutes following the non-oxidizing acid immersion treatment. Immediately after the dipping treatment, it was washed with water and dried with a dryer.
非酸化性酸浸漬処理とその後の酸化性酸浸漬処理が施されたステンレス鋼から試験片を切り出し、ステンレス鋼表面に生成した不動態皮膜の構造をXPSで分析した。XPSでの分析では、Alkα（単色化）の励起線を使い光電子取り出し角を９０度に設定し、皮膜表面からスパッタなしで分析した。使用した分析装置の分析による深さ方向に関する情報量は約５０Åであり、不動態皮膜全体の情報を取り込んでいるものと判断できる。なお、これらの試験片表面には、いずれも５００個程度のマイクロピットが形成されていた。 A test piece was cut out from stainless steel subjected to non-oxidizing acid immersion treatment and subsequent oxidizing acid immersion treatment, and the structure of the passive film formed on the stainless steel surface was analyzed by XPS. In the XPS analysis, Alkα (single color) excitation line was used to set the photoelectron extraction angle to 90 degrees, and the film surface was analyzed without sputtering. The amount of information related to the depth direction by the analysis of the analyzer used is about 50 mm, and it can be determined that the information of the entire passive film is taken in. Note that about 500 micropits were formed on the surfaces of these test pieces.
また、切り出した試験片より、初期接触抵抗及び湿潤試験後の接触抵抗を測定した。初期接触抵抗は、実施例１と同様、試験片を室内に７２時間放置した後、試験片に対し燃料電池における拡散層を形成するカーボンペーパを荷重：１ＭＰａで接触させ、ステンレス鋼／カーボンペーパ間の接触抵抗を測定した。湿潤試験後の接触抵抗は、燃料電池の内部環境を模擬した温度：７０℃，湿度：９８％RHの湿潤環境下に７２時間放置した試験片に同様にカーボンペーパを荷重：１ＭＰａで接触させ、接触抵抗を測定した。
酸化性酸への浸漬時間の違いによる不動態皮膜中のＣｒ／Ｆｅ原子数比及び接触抵抗の変化を表５に示す。
Moreover, from the cut-out test piece, the initial contact resistance and the contact resistance after the wet test were measured. The initial contact resistance was the same as in Example 1. After leaving the test piece in the room for 72 hours, the carbon paper forming the diffusion layer in the fuel cell was brought into contact with the test piece at a load of 1 MPa, and the stainless steel / carbon paper The contact resistance was measured. The contact resistance after the wet test is the same as the test piece left for 72 hours in a wet environment of temperature: 70 ° C. and humidity: 98% RH simulating the internal environment of the fuel cell. Contact resistance was measured.
Table 5 shows changes in the Cr / Fe atomic ratio and contact resistance in the passive film due to the difference in the immersion time in the oxidizing acid.
表５に見られるように、不動態皮膜中の化合物状態のＣｒ／Ｆｅ原子数比は、非酸化性酸に浸漬した状態では、非酸化性酸に浸漬する前よりも小さく１.４となっていた。
これに対して、非酸化性酸浸漬後に、濃度：３０質量％，液温：５０℃の硝酸溶液中に１０分間浸漬する処理を施せば、化合物状態のＣｒ／Ｆｅ原子数比が５.０となり不動態皮膜中のＣｒ濃度が高くなっていた。その結果、接触抵抗は非酸化性酸浸漬のままの状態よりも一段と低くなり、また湿潤環境下においても低接触抵抗を維持できた。
As can be seen from Table 5, the Cr / Fe atomic ratio in the compound state in the passive film is 1.4 smaller in the state immersed in the non-oxidizing acid than in the non-oxidizing acid. It was.
On the other hand, after immersion in a non-oxidizing acid, a treatment of immersion in a nitric acid solution having a concentration of 30% by mass and a liquid temperature of 50 ° C. for 10 minutes gives a compound Cr / Fe atomic ratio of 5.0. The Cr concentration in the passive film was high. As a result, the contact resistance was much lower than that in the non-oxidizing acid immersion state, and the low contact resistance could be maintained even in a wet environment.
次いで、非酸化性酸浸漬処理及びその後の酸化性酸浸漬処理を施したステンレス鋼製セパレータを燃料電池の燃料極側，酸化極側に組み込み、燃料電池を３００時間連続運転した後の電流−電圧特性で評価した。
図３に見られるように、非酸化性酸への浸漬処理後に酸化性酸への浸漬処理を施して不動態皮膜中のＣｒ濃度を増加させたステンレス鋼をセパレータに用いた燃料電池は、出力が最も高かった。一方、非酸化性酸浸漬処理のみを施したステンレス鋼を用いた場合は、やや出力が低かった。さらに、酸浸漬処理を全く施さなかったステンレス鋼を用いた燃料電池では、低い出力しか得られなかった。
Next, the current-voltage after the stainless steel separator subjected to the non-oxidizing acid immersion treatment and the subsequent oxidizing acid immersion treatment is incorporated in the fuel electrode side and the oxidation electrode side of the fuel cell and the fuel cell is continuously operated for 300 hours. The characteristics were evaluated.
As shown in FIG. 3, the fuel cell using stainless steel as a separator, which has been subjected to an immersion treatment in an oxidizing acid after an immersion treatment in a non-oxidizing acid to increase the Cr concentration in the passive film, Was the highest. On the other hand, when stainless steel subjected only to the non-oxidizing acid immersion treatment was used, the output was slightly low. Furthermore, only a low output was obtained in a fuel cell using stainless steel that was not subjected to acid immersion treatment at all.
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001032056A (en) * | 1999-07-22 | 2001-02-06 | Sumitomo Metal Ind Ltd | Stainless steel for conductive parts and solid high polymer type fuel battery |
| JP2001214286A (en) * | 2000-01-31 | 2001-08-07 | Sumitomo Metal Ind Ltd | Method for producing stainless steel for conductive part |
| WO2002023654A1 (en) * | 2000-09-12 | 2002-03-21 | Nisshin Steel Co., Ltd. | Separator for low-temperature type fuel cell and production method therefor |
| JP2002270196A (en) * | 2001-03-07 | 2002-09-20 | Matsushita Electric Ind Co Ltd | High molecular electrolyte type fuel cell and operating method thereof |
| JP2003223904A (en) * | 2001-02-22 | 2003-08-08 | Jfe Steel Kk | Separator for fuel cell, its manufacturing method, and polymer electrolyte fuel cell |
| JP2003297380A (en) * | 2002-04-03 | 2003-10-17 | Nisshin Steel Co Ltd | Stainless steel separator for fuel cell |
| JP2005302713A (en) * | 2004-03-18 | 2005-10-27 | Jfe Steel Kk | Metal material for energizing member, fuel cell separator using it and fuel cell |
-
2006
- 2006-10-03 JP JP2006271388A patent/JP2008091225A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001032056A (en) * | 1999-07-22 | 2001-02-06 | Sumitomo Metal Ind Ltd | Stainless steel for conductive parts and solid high polymer type fuel battery |
| JP2001214286A (en) * | 2000-01-31 | 2001-08-07 | Sumitomo Metal Ind Ltd | Method for producing stainless steel for conductive part |
| WO2002023654A1 (en) * | 2000-09-12 | 2002-03-21 | Nisshin Steel Co., Ltd. | Separator for low-temperature type fuel cell and production method therefor |
| JP2003223904A (en) * | 2001-02-22 | 2003-08-08 | Jfe Steel Kk | Separator for fuel cell, its manufacturing method, and polymer electrolyte fuel cell |
| JP2002270196A (en) * | 2001-03-07 | 2002-09-20 | Matsushita Electric Ind Co Ltd | High molecular electrolyte type fuel cell and operating method thereof |
| JP2003297380A (en) * | 2002-04-03 | 2003-10-17 | Nisshin Steel Co Ltd | Stainless steel separator for fuel cell |
| JP2005302713A (en) * | 2004-03-18 | 2005-10-27 | Jfe Steel Kk | Metal material for energizing member, fuel cell separator using it and fuel cell |
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