Corrosion and electrical properties of CrN- and TiN-coated 316L stainless steel used as bipolar plates for polymer electrolyte membrane fuel cells

Cathode arc ion plating was applied to deposit CrN and TiN coating layers on stainless steel 316L (SS316L) to produce metallic bipolar plates for polymer electrolyte membrane fuel cells (PEMFCs). The interfacial contact resistance between samples and carbon paper was measured and found to be 10 and 23 mΩ ∗ cm2 for TiN and CrN coating layer respectively under 150 N cm− 2 compaction forces. The corrosion properties were investigated in the operating environments of PEMFC. While TiN coating layer was dissolved in the operating environments of PEMFC, the corrosion current density of 0.1 μA cm− 2 was obtained for CrN coating layer at anodic condition and its protective efficiency was revealed as 99%. This analysis indicates that the improvement may be attributed to the extremely dense coating and the synergistic function of the CrN layered structure.