Surface modification and performance of inexpensive Fe-based bipolar plates for proton exchange membrane fuel cells

A reforming pack chromization with rolling pretreatment process is utilized to develop inexpensive and high-performance Fe-based metal bipolar plates (SS 420, SS 430, and SS 316 stainless steels) for PEMFC systems. Rolling process is previously performed to reduce the chromizing temperature and generate a coating possessing excellent conductivity and corrosion resistance on the steels during chromization. The power efficiencies of rolled-chromized and simple chromized bipolar plates are compared with graphite bipolar plates employed in PEMFCs. The results show that the rolled-chromized bipolar plates have a corrosion current (Icorr) of 7.87 × 10−8 A cm−2 and an interfacial contact resistance of 9.7 mΩ cm2. Moreover, the power density of the single cell assembled with rolled-chromized bipolar plates is 0.46 W cm−2, which is very close to that of graphite (0.50 W cm−2), in the tested conditions of this study.