Studying Protective Coatings on Titanium Bipolar Fuel Cell Plates Obtained by Hot Target Magnetron Sputtering

Abstract

The results of investigations of functional chromium nitride-based coatings obtained by magnetron sputtering of a hot (uncooled) chromium target at different nitrogen contents are reported. The CrN coatings should provide a low-resistance contact in a densely packed fuel cell stack and corrosion protection of fuel cell stack components based on hydrogen‒air fuel cells with a proton-exchange membrane. It is shown that the use of hot targets, compared with the use of cooled ones, allows an almost two-fold increase in the productivity of the coating application process. This changes the surface morphology and structure of the CrN films and the surface contact resistance at the gas diffusion electrode–bipolar plate interface of the PEM fuel cell decreases to R_s = 1.34 mΩ cm². As the nitrogen content in the argon plasma increases at the same hot target magnetron sputtering time, the rate of formation of the protective films increases and the surface contact resistance decreases, while their corrosion characteristics deteriorate.