Corrosion protection of Ti/TiN, Cr/TiN, Ti/CrN, and Cr/CrN multi-coatings in simulated proton exchange membrane fuel cell environment

The coating performance can be improved by reducing the number of defects of a coating by layering two materials on the nanometer scale. In this study, Ti/TiN, Cr/TiN, Ti/CrN, and Cr/CrN multilayer coatings were examined to determine the corrosion resistance of the multi-coating system and to obtain information on the appropriate materials for bipolar plates in proton exchange membrane fuel cells. The results showed that the Cr/CrN coating gains excellent coating performance due to the lowest passive current density as well as the highest protective efficiency and charge transfer resistance. X-ray diffraction analysis confirmed the formation of a preferred (111) orientation along with crystalline-refined (200).