Stainless steel for fuel cell separator

A stainless steel for fuel cell separators wherein the stainless steel contains, by mass, C:

• not more than 0.03%, Si:
• not more than 1.0%, Mn:
• not more than 1.0%, S:
• not more than 0.01%, P:
• not more than 0.05%, Al:
• not more than 0.20%, N:
• not more than 0.03%, Cr:
• 16 to 40%, and one or more of Ni:
• not more than 20%, Cu:
• not more than 0.6% and Mo:
• not more than 2.5%, the balance being Fe and inevitable impurities, and
• wherein according to X-ray photoelectron spectroscopy, the surface of the stainless steel contains fluorine and satisfies the following relation:
• (Cr+Fe) in other than metallic forms/(Cr+Fe) in metallic forms≧3.0
• wherein (Cr+Fe) in other than metallic forms indicates the total of atomic concentrations of Cr and Fe in other than the metallic forms calculated from data resulting from the separation of peaks of Cr and Fe into metallic peaks and peaks other than the metallic peaks, and (Cr+Fe) in metallic forms indicates the total of atomic concentrations of Cr and Fe in the metallic forms calculated from the data resulting from the separation of the peaks of Cr and Fe into metallic peaks and peaks other than the metallic peaks.