The effect of thiocyanate ions on the corrosion of copper in perchloric acid

Abstract

The effect of thiocyanate ions on the corrosion of copper in 0.1 M HClO4 was investigated in the presence of various concentrations of thiocyanate ions using weight loss and polarization methods. The corrosion rate decreased markedly in the presence of thiocyanate ions and maximum percentage protection (93.7%) was obtained at 10-3 M thiocyanate ions. The drift of the corrosion potential in the less noble direction and the increase in the anodic Tafel slope are consistent with the inhibition by thiocyanate ions of both the anodic and the cathodic reactions of the corrosion process. The variation in the corrosion rate with the concentration of thiocyanate ions is attributed to the specific adsorption of thiocyanate ions and precipitation of cuprous thiocyanate on the copper surface. © 1980