Investigation of the corrosion stability of stainless steels under simulated low and high temperature proton exchange membrane fuel cell operating conditions

Stainless steels for low and high temperature proton exchange membrane fuel cell present several advantages over graphitic materials. The fabrication of bipolar plates from these kinds of alloys could reduce weight of the stack and provide high mechanical stability. Test results show that bipolar plates fabricated from standard V2A or V4A steel can withstand the corrosive conditions in a low-temperature (50 {degree sign}C) proton exchange membrane fuel cell. For water cooled applications with an operating temperature around 80 {degree sign}C and thus resulting heavily corrosive conditions, two high-alloyed steel specimens have proven to be suitable. Further analyses show variations in corrosion resistance after pre-treating steel samples with e.g. physicochemical surface treatments, electro-polishing, thermal annealing and corrosion protective coating solution. The high temperature PEMFC test condition with 85% phosphoric acid and 160 {degree sign}C operation temperature leads to visible corrosion traces on all specimens except one.