Aqueous potential-pH equilibria in copper-benzotriazole systems

Thermodynamic data, together with equilibria involving 1-H-benzotriazole (BTAH) and cuprous benzotriazole species (CuBTA), have been used to construct aqueous E-pH diagrams for Cu-BTAH-H2O and Cu-BTAH-Cl~ H2O systems. The diagrams are the first of their kind for BTAH-containing solutions and show the domains of stability of the CuBTA salt. They are in reasonable agreement with the reported major effects of multilayer CuBTA polymer films on the corrosion inhibition of copper. Some kinetic considerations are discussed and the overall results provide a basis for understanding the combined effects of E, pH, Cl-, and BTAH concentrations (activities) on corrosion inhibition of Cu. 2 figs., 1 tab., 15 refs.