Corrosion Behavior of WC–10 wt % Ni 3 Al Composite in Acidic Media

The room temperature corrosion behavior of WC–10 wt % Ni 3 Al composite and WC–8 wt % Co hardmetal in various acidic solutions (1 M H 2 SO 4 , 1 M HCl and 1 M HNO 3 ) were compared and investigated utilizing immersion test, electrochemical measurement and surface analytical techniques. The results show that in H 2 SO 4 solution WC–10Ni 3 Al composite has a nobler free corrosion potential, lower corrosion current density ( I corr ) values and intrinsically better corrosion resistance than WC–8Co. Notably, pseudopassivity was observed in the polarization curves of WC–10Ni 3 Al in both HCl and H 2 SO 4 solutions. In addition, although WC–10Ni 3 Al is corroded much faster in HNO 3 solution than in the other two mediums, it exhibits a superior corrosion resistance compared to WC–8Co. The corrosion mechanism of WC–10Ni 3 Al composites is dominated by Ni dissolution.