Stainless steel material for a separator of a solid polymer fuel cell and a solid polymer fuel cell using the separator

A stainless steel member for a separator of a solid polymer fuel cell, the member comprising:

• a stainless steel base metal;
• an oxide film located on a surface of the stainless steel base metal;
• an electroconductive layer located on a surface of the oxide film opposite to the oxide film surface located on the stainless steel base metal, and comprising a nonmetallic electroconductive material, wherein the nonmetallic electroconductive material comprises graphite and the value of a lattice spacing of d002 of the graphite is at most 3.390 angstroms;
• and
• an electroconductive material which is located so as to penetrate the oxide film and which electrically contacts the stainless steel base metal and the electroconductive layer;
• wherein when comparing peak intensities of diffraction lines of atomic planes of a crystal of the graphite located on the surface of the oxide film as measured by wide-angle X-ray diffraction, the ratio of a peak intensity of a diffraction line of a (110) atomic plane to a peak intensity of a diffraction line of a (004) atomic plane is less than 0.1,
• wherein the electroconductive material is formed of a boride-type metallic inclusion which has a M2B-type structure and which is partly embedded in the stainless steel base metal, wherein M is a metal.