Interrelation between partial reactions during alternating-current polarization of copper in chloride environments

Infralow-frequency alternating-current polarization of a copper electrode in chloride environments causes an increase in the pH of a near-electrode layer, as well as the concentration of hydroxide ions adsorbed at the electrode, during the cathodic half-period. This facilitates the oxidation of copper during the subsequent anodic half-period and changes the character of the oxidation products, that is, instead of soluble, insoluble compounds form. During the anodic half-period, consumption of hydroxide ions restores the initial pH in a near-electrode layer. The oxidation products of copper may become soluble again.