Ferritic stainless steel for fuel cell and method for producing the same
AssigneeNippon Steel & Sumikin Stainless Steel Corporation
InventorsMasaharu HATANO, Atsutaka HAYASHI, Kazuhisa MATSUMOTO
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Abstract
A ferritic stainless steel for a fuel cell includes, in mass %, Cr: 11 to 25%, C: 0.03% or less, Si: 2% or less, Mn: 2% or less, Al: 0.5 to 4.0%, P: 0.05% or less, S: 0.01% or less, N: 0.03% or less, Ti: 1% or less, and a balance composed of Fe and unavoidable impurities. Furthermore, in the ferritic stainless steel, the maximal concentration of Al in a surface of the ferritic stainless steel is 30 mass % or more in cation ion fraction excepting 0 in an depth direction region having twice a thickness of an oxide film having less than 0.1 μm.
Claims32
A ferritic stainless steel for a fuel cell comprising, in mass %, Cr:
- 11 to 25%, C:
- 0.03% or less, Si:
- 2% or less, Mn:
- 2% or less, Al:
- 0.5 to 4.0%, P:
- 0.05% or less, S:
- 0.01% or less, N:
- 0.03% or less, Ti:
- 1% or less, and a balance composed of Fe and unavoidable impurities, wherein,
- a maximal concentration of Al in a surface of the ferritic stainless steel is 30 mass % or more in cation ion fraction excepting O in an depth direction region having twice a thickness of an oxide film having less than 0.1 μm.
A ferritic stainless steel for a fuel cell comprising, in mass %, Cr:
- 11 to 25%, C:
- 0.03% or less, Si:
- 2% or less, Mn:
- 2% or less, Al:
- 0.5 to 4.0%, P:
- 0.05% or less, S:
- 0.01% or less, N:
- 0.03% or less, Ti:
- 1% or less, and a balance composed of Fe and unavoidable impurities, wherein,
- a maximal concentration of Al in a surface of the ferritic stainless steel is 30 mass % or more in cation ion fraction excepting O in an depth direction region having twice a thickness of an oxide film having less than 0.1 μm, after heating the ferritic stainless steel in an atmosphere containing 50 vol % or more of hydrogen gas and a balance substantively composed of nitrogen gas at a temperature of 800 to 1000° C. within 10 minutes or less and cooling thereof to room temperature.
A ferritic stainless steel for a fuel cell comprising, in mass %, Cr:
- 11 to 25%, C:
- 0.03% or less, Si:
- 2% or less, Mn:
- 2% or less, Al:
- 0.5 to 4.0%, P:
- 0.05% or less, S:
- 0.01% or less, N:
- 0.03% or less, Ti:
- 1% or less, and a balance composed of Fe and unavoidable impurities, wherein,
- a maximal concentration of Al in a surface of the ferritic stainless steel is 30 mass % or more in cation ion fraction excepting O in an depth direction region having twice a thickness of an oxide film having less than 0.1 μm, after heating the ferritic stainless steel in an atmosphere of air at a temperature of 850° C. for 100 hours and cooling thereof to room temperature.
A ferritic stainless steel having advantages of a resistance to Cr vaporizing for a fuel cell comprising, in mass %, Cr:
- 11 to 25%, C:
- 0.03% or less, Si:
- 2% or less, Mn:
- 2% or less, Al:
- 0.5 to 4.0%, P:
- 0.05% or less, S:
- 0.01% or less, N:
- 0.03% or less, Ti:
- 0.5% or less, and a balance composed of Fe and unavoidable impurities, wherein,
- the ferritic stainless steel further comprises one or two or more of elements selected from a group consisting of Ga:
- 0.1% or less, Mg:
- 0.01% or less and Zn:
- 0.05% or less,
- a total amount Ga+Mg+Zn satisfies Ga+Mg+Zn>0.001%, and
- a balance is composed of Fe and unavoidable impurities.
Dependencies are inferred from the claim text.