Surface diffusion modification AISI 304SS stainless steel as bipolar plate material for proton exchange membrane fuel cell

Fe-based stainless steels are the promising candidate materials for bipolar plate of proton exchange membrane fuel cell (PEMFC) due to low cost, ease stamping manufacture, good heat and electric conductivity. A surface modification technology of electroplating Cr followed by heat-diffusion in vacuum furnace is applied for AISI 304SS stainless steel in this paper to improve the Interfacial Contact Resistance (ICR) and corrosion resistance. The electrochemical tests such as potentiodynamic and potentiostatic polarization in the simulation PEMFC environments are carried out and the ICR between the carbon paper (diffusion layer) and the sample is evaluated. The results show that ICR is reduced markedly and corrosion resistance is better than the untreated substrate steel. The modified stainless steel with high Cr surface may be better candidate for the bipolar plates of PEMFC. After polarization, the contact resistance increased in some content. A surface nitride formation is under going on to lower the ICR further.