A ferritic stainless steel material is provided that has a chemical composition containing, by mass %, C: 0.001 to less than 0.020%, Si: 0.01 to 1.5%, Mn: 0.01 to 1.5%, P: 0.035% or less, S: 0.01% or less, Cr: 22.5 to 35.0%, Mo: 0.01 to 6.0%, Ni: 0.01 to 6.0%, Cu: 0.01 to 1.0%, N: 0.035% or less, V: 0.01 to 0.35%, B: 0.5 to 1.0%, Al: 0.001 to 6.0%, Sn: 0.02 to 2.50%, rare earth metal: 0 to 0.1%, Nb: 0 to 0.35%, Ti: 0 to 0.35%, and the balance: Fe and impurities, in which a value calculated as {Cr content (mass %)+3×Mo content (mass %)−2.5×B content (mass %)} is from 20 to 45%, and M.sub.2B boride-based metallic precipitates are dispersed in and exposed on the surface of a parent phase composed only of a ferritic phase.

A ferritic stainless steel material contains, by mass %, C: 0.02 to 0.15%, Si: 0.01 to 1.5%, Mn: 0.01 to 1.5%, P: 0.035% or less, S: 0.01% or less, Cr: 22.5 to 35.0%, Mo: 0.01 to 6.0%, Ni: 0.01 to 6.0%, Cu: 0.01 to 1.0%, N: 0.035% or less, V: 0.01 to 0.35%, B: 0.5 to 1.0%, Al: 0.001 to 6.0%, rare earth metal: 0 to 0.10%, Sn: 0 to 2.50%, and the balance: Fe and impurities, and a value calculated in mass % as {Cr+3×Mo−2.5×B−17×C} ranges from 20 to 45%. The ferritic stainless steel material has a parent phase comprising only a ferritic phase. At least composite metallic precipitates including M.sub.23C.sub.6 carbide-based metallic precipitates precipitated on surfaces and at peripheries of M.sub.2B boride-based metallic precipitates serving as precipitation nuclei are dispersed and exposed on a parent phase surface.

A ferritic stainless steel material contains, by mass %, C: 0.02 to 0.15%, Si: 0.01 to 1.5%, Mn: 0.01 to 1.5%, P: 0.035% or less, S: 0.01% or less, Cr: 22.5 to 35.0%, Mo: 0.01 to 6.0%, Ni: 0.01 to 6.0%, Cu: 0.01 to 1.0%, N: 0.035% or less, V: 0.01 to 0.35%, B: 0.5 to 1.0%, Al: 0.001 to 6.0%, rare earth metal: 0 to 0.10%, Sn: 0 to 2.50%, and the balance: Fe and impurities, and a value calculated in mass % as {Cr+3×Mo−2.5×B−17×C} ranges from 20 to 45%. The ferritic stainless steel material has a parent phase comprising only a ferritic phase. At least composite metallic precipitates including M.sub.23C.sub.6 carbide-based metallic precipitates precipitated on surfaces and at peripheries of M.sub.2B boride-based metallic precipitates serving as precipitation nuclei are dispersed and exposed on a parent phase surface.

The present invention provides a stainless steel including 21 to 23% by mass of Cr, 0.2 to 0.4% by mass of Mn, 1.0 to 2.0% by mass of Mo, 0.08 to 2.0% by mass or Al, 0.01 to 0.2% by mass of Ti, and 0.2 to 0.5% by mass of Nb, with the balance being Fe and inevitable impurities; an interconnector of a fuel cell or a base material for holding a cell of a fuel cell made of this stainless steel; and a solid oxide fuel cell including this interconnector or this base material for holding a cell.

The present invention provides a stainless steel including 21 to 23% by mass of Cr, 0.2 to 0.4% by mass of Mn, 1.0 to 2.0% by mass of Mo, 0.08 to 2.0% by mass or Al, 0.01 to 0.2% by mass of Ti, and 0.2 to 0.5% by mass of Nb, with the balance being Fe and inevitable impurities; an interconnector of a fuel cell or a base material for holding a cell of a fuel cell made of this stainless steel; and a solid oxide fuel cell including this interconnector or this base material for holding a cell.

A metal support for an electrochemical element has a plate shape as a whole, and is provided with a plurality of penetration spaces that pass through the metal support from a front face to a back face. The front face is a face to be provided with an electrode layer. Each of front-side openings that are openings of the penetration spaces formed in the front face has an area of 3.0×10.sup.−4 mm.sup.2 or more and 3.0×10.sup.−3 mm.sup.2 or less.

Ferritic stainless steel is characterized by including, by mass %: Cr: 12.0% to 16.0%; C: 0.020% or less; Si: 2.50% or less; Mn: 1.00% or less; P: 0.050% or less; S: 0.0030% or less; Al: 2.50% or less; N: 0.030% or less; Nb: 0.001% to 1.00%; one or more of B: 0.0200% or less, Sn: 0.20% or less, Ga: 0.0200% or less, Mg: 0.0200% or less, and Ca: 0.0100% or less; and a balance consisting of Fe and impurities, in which Expression (1) is satisfied.
10(B+Ga)+Sn+Mg+Ca>0.020  (1)

Provided is a ferrite-based stainless steel having superior moldability when molding a fuel cell divider sheet from a material by controlling yield point elongation in accordance with alloy components. The ferrite-based stainless steel comprises, in weight percentages: no more than 0.02% of C; no more than 0.02% of N; no more than 0.4% of Si; no more than 0.2% of Mn; no more than 0.04% of P; no more than 0.02% of S; 25.0-32.0% of Cr; 0-1.0% of Cu; no more than 0.8% of Ni; no more than 0.01-0.5% of Ti; no more than 0.01-0.5% of Nb; no more than 0.01-1.5% of V; and residual Fe and inevitable elements, wherein the content of Ti, Nb, V, C, and N in terms of weight % of steel uses Formula (1) to render a yield point elongation of the material of no more than 1.1%, and wherein a steel material has superior moldability.
9.1C−1.76V+5.37(C+N)/Ti−1.22Nb≦0.7.  Formula (1)

Provided is a ferrite-based stainless steel having superior moldability when molding a fuel cell divider sheet from a material by controlling yield point elongation in accordance with alloy components. The ferrite-based stainless steel comprises, in weight percentages: no more than 0.02% of C; no more than 0.02% of N; no more than 0.4% of Si; no more than 0.2% of Mn; no more than 0.04% of P; no more than 0.02% of S; 25.0-32.0% of Cr; 0-1.0% of Cu; no more than 0.8% of Ni; no more than 0.01-0.5% of Ti; no more than 0.01-0.5% of Nb; no more than 0.01-1.5% of V; and residual Fe and inevitable elements, wherein the content of Ti, Nb, V, C, and N in terms of weight % of steel uses Formula (1) to render a yield point elongation of the material of no more than 1.1%, and wherein a steel material has superior moldability.
9.1C−1.76V+5.37(C+N)/Ti−1.22Nb≦0.7.  Formula (1)

A separator includes a gas flow path forming body, which includes a substrate made of stainless steel, a resin layer arranged on the substrate, and a conductive layer arranged on the surface of the resin layer. The resin layer contains a filler, which has conductivity and greater hardness than an oxide film of the substrate. The conductive layer contains graphite. The filler extends through the oxide film of the substrate and contacts the base material.