STAINLESS STEEL, COMPONENT, CELL AND FUEL CELL STACK

• Main Authors: TARUYA YOSHIO, SATO HISASHI, NISHIMOTO TAKUMI
• Format: Patent
• Language: English; Japanese
• Published: 05.09.2019
• Subjects: ALLOYS; BASIC ELECTRIC ELEMENTS; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; ELECTRICITY; FERROUS OR NON-FERROUS ALLOYS; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; TREATMENT OF ALLOYS OR NON-FERROUS METALS

To provide a stainless steel that has excellent oxidation resistance, has low contact resistance, and can prevent a deterioration of battery performance due to sublimation of Cr, a component employing the stainless steel, a cell and a fuel cell stack.SOLUTION: A stainless steel has a base material composed of ferritic stainless steel, and a surface modification layer formed on the surface of the base material. The base material has a chemical composition satisfying [16.0≤Cr-2.5×B-17×C≤30.0]. In the chemical composition of the surface modification layer, the proportions of Cr, Al, C and B contents represented by [[Cr]: [Al]: [C]: [B]=1: x: y: z] satisfy [0.4≤x≤0.6], [0.4≤y+z≤0.6]and [z/y≤0.5]. The base material contains MCCr carbide or the like. The deposit partially projects from the surface of the surface modification layer.SELECTED DRAWING: Figure 1 【課題】耐酸化性に優れ、かつ、接触抵抗が低く、さらにＣｒの昇華による電池性能の低下を抑制しうるステンレス鋼材、前記ステンレス鋼材を適用した構成部材、セルおよび燃料電池スタックを提供する。【解決手段】フェライト系ステンレス鋼からなる基材と、該基材の表面上に形成された表面改質層とを備え、前記基材の化学組成が、［１６．０≦Ｃｒ−２．５×Ｂ−１７×Ｃ≦３０．０］を満足し、前記表面改質層の化学組成において、［［Ｃｒ］：［Ａｌ］：［Ｃ］：［Ｂ］＝１：ｘ：ｙ：ｚ］で示されるＣｒ、Ａｌ、ＣおよびＢの成分量の比が、［０．４≦ｘ≦０．６］、［０．４≦ｙ＋ｚ≦０．６］および［ｚ／ｙ≦０．５］を満足し、前記基材中に、Ｍ２３Ｃ６型Ｃｒ系炭化物等を有し、前記析出物は、その一部が前記表面改質層の表面から突出している、ステンレス鋼材。【選択図】図１