A STUDY OF THE ELECTROCHEMICAL FORMATION OF CU(I)-BTA FILMS ON COPPER ELECTRODES AND THE MECHANISM OF COPPER CORROSION INHIBITION IN AQUEOUS CHLORIDE BENZOTRIAZOLE SOLUTIONS

Cu electrode behaviour in Cl- and benzotriazole (H-BTA) containing acidic or neutral solutions was studied by voluntary, ammetry, photocurrent response, impedance measurements and chemical analysis of BTA consent in passive layers. It was shown that the rate of formation of Cu-BTA films in acidic solutions is controlled by the transport of CuCl2- ions through pores in the film at an early stage of film formation and later by the volume diffusion rate in the film. The photocurrent measurements have revealed that Cu-BTA formation is accompanied by the simultaneous deposition of a Cu2 O underlayer. The main portion of the polarisation resistance of the passive layer was ascribed to the Cu2 O underlayer. It is proposed that the role of the Cu-BTA overlayer is to stabilize the Cu2 O underlayer and maintain its high resistance by preventing it from being doped by Cl- ions resulting in the formation of solid CuCl on tope of the Cu2O.