Fuel cell separator with chromium rich surface layer and method of producing the fuel cell separator

A method of producing a fuel cell separator forming part of a unit cell of a fuel cell, said unit cell being formed by interposing an electrolyte electrode assembly between a pair of the fuel cell separators, said electrolyte electrode assembly including an anode, a cathode, and an electrolyte interposed between said anode and said cathode, the method comprising the steps of:

• heating said fuel cell separator to aggregate Fe in a surface layer of said fuel cell separator to form an Fe rich layer, and providing a Cr rich layer in an inner portion of said fuel cell separator by movement of Fe toward the surface layer, wherein
• said Cr rich layer having a higher Cr proportion by weight with respect to the weight of the Cr and Fe in comparison with other portions and
• the proportion of Cr in said Cr rich layer being 70% or more by weight with respect to the weight of the Cr and Fe;
• and
• applying an electrolytic treatment to said fuel cell separator to remove said Fe rich layer, and expose said Cr rich layer to the outside on a surface of said fuel cell separator.