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

Cu electrode behaviour in Cl- and benzotriazole (H-BTA) containing aci dic or neutral solutions was studied by voluntary, ammetry, photocurre nt response, impedance measurements and chemical analysis of BTA conse nt in passive layers. It was shown that the rate of formation of Cu-BT A films in acidic solutions is controlled by the transport of CuCl2- i ons through pores in the film at an early stage of film formation and later by the volume diffusion rate in the film. The photocurrent measu rements have revealed that Cu-BTA formation is accompanied by the simu ltaneous deposition of a Cu2 O underlayer. The main portion of the pol arisation resistance of the passive layer was ascribed to the Cu2 O un derlayer. It is proposed that the role of the Cu-BTA overlayer is to s tabilize the Cu2 O underlayer and maintain its high resistance by prev enting it from being doped by Cl- ions resulting in the formation of s olid CuCl on tope of the Cu2O.