| abstract |
A titanium or titanium alloy material for a separator of a polymer electrolyte fuel cell having high contact conductivity with carbon and high durability, and including an oxide film formed on a titanium or titanium alloy substrate by a stabilization treatment performed after a passivation treatment, and one or more kinds of conductive materials selected from carbide, nitride, carbonitride, and boride of tantalum, titanium, vanadium, zirconium, and chromium, the conductive materials being dispersed in the oxide film and having a major axis diameter of from 1 nm to 100 nm. A contact resistance value with a carbon paper is 20 mΩ·cm 2 or less at a surface pressure of 10 kgf/cm 2 before and after an accelerated deterioration test in which the titanium or titanium alloy material is immersed in a sulfuric acid aqueous solution having an adjusted pH of 4 at 80° C. for four days. |