Stainless steel material, constituting component, cell, and fuel cell stack

A stainless steel material comprising:

• a base material made of ferritic stainless steel;
• a Cr oxide layer formed on a surface of the base material;
• and a spinel-type transition metal oxide layer formed on a surface of the Cr oxide layer, wherein
• a chemical composition of the base material satisfies a following formula (i),
• a thickness of the Cr oxide layer and a thickness of the spinel-type transition metal oxide layer satisfy a following formula (ii),
• the base material contains precipitate including a M23C6-type Cr carbide,
• a part of the precipitate of the base material that contains precipitate protrudes from the surface of the Cr oxide layer:
• 16.0≤Cr+3×Mo−2.5×B−17×C−3×Si≤35.0 (i)
• 0.5≤TCr/TS≤6.7 (ii)
• where each symbol of an element in the formula (i) means content (mass %) of each element contained in the base material, and meaning of each symbol in the formula (ii) is as follows
• TCr:
• thickness of Cr oxide layer
• Ts:
• thickness of spinel-type transition metal oxide layer,
• wherein the chemical composition of the base material consists of, by mass %:
• C:
• more than 0.02% and 0.15% or less;
• Si:
• 0.15 to 0.8%;
• Al:
• 0.001 to 0.025%;
• Mn:
• 0.01 to 1.0%;
• P:
• 0.045% or less;
• S:
• 0.010% or less;
• N:
• 0.05% or less;
• V:
• 0.5% or less;
• Cr:
• 17.0 to 32.5%;
• Mo:
• 0 to 4.5%;
• Ni:
• 0 to 2.5%;
• Cu:
• 0.01 to 0.8%;
• W:
• 0 to 4.0%;
• Co:
• 0 to 4.0%;
• Ti:
• 0 to 6.5×C %;
• Nb:
• 0 to 6.5×C %;
• Sn:
• 0 to 0.05%;
• In:
• 0 to 0.05%;
• Sb:
• 0 to 0.01%;
• Ca:
• 0 to 0.10%;
• Mg:
• 0 to 0.10%;
• REM:
• 0 to 0.10%;
• B:
• 0 to 1.0%;
• and
• the balance:
• Fe and impurity.