Effect of surface treatment on the interfacial contact resistance and corrosion resistance of Fe-Ni-Cr alloy as a bipolar plate for polymer electrolyte membrane fuel cells

The bipolar plate is an important component of the PEMFC (polymer electrolyte membrane fuel cell) because it supplies the pathway of electron flow between each unit cell. Fe-Ni-Cr alloy is considered as a good candidate material for bipolar plate, but it is limited to use as a bipolar plate due to its high ICR (interfacial contact resistance) and corrosion problem. In order to explore a cost-effective method on surface modification, various chemical and electrochemical treatments are performed on Fe-Ni-Cr alloy to acquire the effect of the surface modification on the ICR and corrosion behavior. The ICR and corrosion resistance of Fe-Ni-Cr alloy can be effectively controlled by the chemical treatment of immersion in the mixed acid solution with 10 vol% HNO3, 2 vol% HCl and 1 vol% HF for 10 min at 65 °C and then was placed in 30 vol% HNO3 solution for 5 min. The chemical treatment is more effective on reducing ICR and improving corrosion resistance than that of electrochemical methods (be carried out in the 2 mol/L H2SO4 solution with the electrical potential from −0.4 V to 0.6 V) for Fe-Ni-Cr alloy as a bipolar plate for polymer electrolyte membrane fuel cells.