Effects of tungsten carbide and cobalt particles on corrosion and wear behaviour of copper matrix composite

Copper matrix composites reinforced with various contents (10–20 wt-%) and sizes (1–9 μm) of tungsten carbide particles (WC_p) and cobalt particles (Co_p, 1·5 μm and 5 wt-%) were fabricated by hot pressing. The effects of WC_p and Co_p on the wear and corrosion properties of the copper composites were evaluated. Dry wear testing was conducted in ambient conditions and wear corrosion testing was carried out in 3·5 wt-%NaCl solution (pH 6·7). The results show that the hardness, wear resistance and static corrosion weight loss of Cu/WC_p composites increase with a decrease of WC_p size or with an increase of WC_p content. Also, the corrosion current density I _corr increases with a decrease of WC_p size or with an increase of WC_p content, and the corrosion potential E _corr exhibits no specific trend with varying WC_p content and size. The wear corrosion rate increases with an increase in WC_p content, yet shows no direct correlation with WC_p size. On the other hand, Cu/WC_p/Co_p composites exhibit better wear resistance in both dry wear and corrosive wear conditions. The Cu/WC_p/Co_p composites show a much lower E _corr and significantly more passivity than Cu/WC_p composites in polarisation tests. The Cu/WC_p/Co_p composites exhibit excellent wear corrosion resistance, especially in the passive potential (E_p) state.