Corrosion and electrical properties of carbon/ceramic multilayer coated on stainless steel bipolar plates

A carbon/ceramic multilayer is deposited onto the stainless steel to enhance the corrosion and electrical properties of metallic bipolar plates under polymer electrolyte membrane fuel cells (PEMFCs). The multilayer is composed of 1.22 μm CrN and 7 nm carbon layers. The corrosion durability tests conducted in an aggressive environments of the PEMFC reveal that a low corrosion current density of 0.12 and 0.07 μA cm− 2 is obtained for the multilayers at anodic and cathodic conditions, respectively, and the highest protective efficiency of 99.80% is recorded in the cathodic condition. Furthermore, the interfacial contact resistance of the carbon/ceramic multilayer is also reduced significantly, by seventeen times, compared to bare stainless steel. A low value of ICR is maintained even after corrosion tests. These tests show that the carbon/ceramic multilayer deposited onto the stainless steel improve the corrosion resistance of the metal substrate and lead to high surface conductivity in the aggressive environments of the PEMFC.