Corrosion behavior of TiC/amorphous carbon coated stainless steel as bipolar plate for proton exchange membrane fuel cell

PurposeThe purpose of this paper is to improve the corrosion resistance of stainless-steel bipolar plate by magnetron sputtering. Design/methodology/approachTiC/amorphous carbon composite film was deposited by magnetron sputter at four different temperature of 25 degrees C, 200 degrees C, 300 degrees C and 400 degrees C. The morphology, composition and structure of the film were characterized by scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. And its corrosion behavior was analyzed through electrochemical impedance spectroscopy, potentiodynamic and potentiostatic polarization tests. FindingsA compact TiC/amorphous carbon film was prepared by magnetron sputtering on 316L stainless steel, and the particles of the film were refined with the increase in sputtering temperature. High temperature promoted the formation of TiC and C-C sp(2) hybrid carbon, but excessively high temperature caused the oxidation of Ti and a significant decrease in sp(2) hybrid carbon. The corrosion resistance of the film increased with the temperature, and the corrosion current density polarization at 0.86 V and 1.8 V for TiC/a-C film prepared at 400 degrees C is only 1.2% and 43.2% of stainless steel, respectively. Originality/valueThe corrosion resistance of amorphous carbon films was improved by the doping of Ti carbide, and the appropriate sputtering temperature was obtained.