Study on behavior of plasma nitrided 316L in PEMFC working conditions

Stainless steel bipolar plates for the polymer electrolyte membrane fuel cell (PEMFC) offer many advantages over conventional machined graphite and graphite-composites. However, the interfacial ohmic loss between the metallic bipolar plate and membrane electrode assembly due to corrosion decreases the overall power output of PEMFC. A lower temperature (at 370 °C) plasma nitriding was applied to modify the surface of stainless steel 316L bipolar plates. The results of electrochemical measurements show that corrosion resistance of the plasma nitrided 316L is improved in simulated PEMFC anode/cathode environments purged with H2/air at 70 °C. The surface conductivity of the nitrided layer is better than that of the air-formed oxide film. The interfacial contact resistance (ICR) between the passive film and carbon paper increases very little after potentiostatic polarization for 4 h, which indicates potential for good stability of this material in highly corrosive fuel cell environments.