Application of photoelectrochemical methods for the characterization of Cu(I) oxide layers modified in the presence of corrosion inhibitors

The influence of azole-type corrosion inhibitors (benzotriazole, mercaptobenzothiazole or mercaptobenzoxazole) on the photoelectrochemical behaviour of copper electrodes under open-circuit potential was investigated in a 0.5 M NaCl solution. A correlation between the inhibition efficiency of an inhibitor, the oxide layer thickness, the polarization resistance and the semiconducting properties of the Cu2O layer more or less stabilized by the inhibitor was proposed. It appeared that a protective oxide layer is characterized by simultaneous p and n-type conductivities, and by a decrease of the photocurrent in the cathodic range, with increasing immersion time.