Corrosion resistance of W–Cr–C coatings fabricated by spark plasma sintering method

Abstract

To increase the corrosion resistance of tungsten, W–Cr–C coatings were fabricated on the tungsten matrix with spark plasma sintering (SPS) method from graphite and chromium powders. SEM and XRD analysis illustrated that W–Cr–C coatings with a thickness of 25μm were composed of tungsten carbide layer and chromium carbide (Cr7C3 and Cr3C2) particles distributed in the surface layer of the coatings. The incorporation of chromium carbide largely enhanced the compactness of coating surface and refined the WC grains. In the immersion experiments, W–Cr–C composite coating exhibited better corrosion resistance than pure WC coating after exposure to the de-ionized water for 38days at both room temperature and 60°C. Electrochemical measurement showed that the reinforcement of chromium carbides can largely improve the corrosion resistance of WC coating in a 3.5% NaCl solution.