An electrochemical study of the formation of Benzotriazole surface films on Copper, Zinc and a Copper-Zinc alloy

The electrochemical behaviour of Cu, Cu-37Zn and Zn in benzotriazole (BTA) containing chloride solutions was studied and compared using potentiodynamic, cyclic voltammetry and electrochemical impedance spectroscopy. The presence of BTA in the chloride-containing solutions gave rise to higher breakdown potentials, significantly higher polarisation resistances and inhibited the formation of CuCl2 and zinc-containing corrosion products. These effects were observed for pure Cu, Cu-Zn and to a somewhat lesser extent pure Zn. The electrochemical impedance data were consistent with the formation of a polymeric BTA-containing layer for all three systems.