Anti-corrosion performance of the conductive bilayer CrC/CrN coated 304SS bipolar plate in acidic environment

A bilayer CrC/CrN coating prepared on 304 stainless steels (304SS) using reactive radio frequency magnetron sputtering technique (RF-MS) is investigated in acidic fuel cell environment. Compared to the CrN monolayer, the synergistic function of bilayer structure effectively hinder penetration of corrosive substance through defects, significantly increases anti-corrosion of substrate. This is attributed to the increased compactness of coating and the good matching between layers to effectively enhance interfacial adhesion. Interfacial contact resistance (ICR) of the CrC/CrN covered 304SS is lower than that of substrate. These effects are closely associated with inherent characteristic and combined preparation method of the coating.