Corrosion inhibition of copper by heterocyclic compounds

The corrosion inhibition of copper in aerated 0.5 M H2SO4 solution in presence of two classes of heterocyclic compounds, namely phenylazo-pyrazolones (PAP) or hydroxy quinoline and bromobenzyl-carboxy-1,2,3 triazole (BCT) derivatives was studied. The corrosion parameters were obtained at different inhibitor concentrations and the temperature effect was also investigated. The corrosion rate of copper was determined; using Tafel method and the polarization resistance (R-P) technique. The electrolyte solution was analysed using cyclic voltammetry and UV-visible spectroscopy. The results were compared with that of some prepared Cu-complexes in order to explain the inhibition mechanism. Moreover, the thermodynamic activation parameters of the Cu-corrosion reaction were calculated and discussed in relation to the stability of the protective layer. The inhibition effect was attributed to the adsorption of the dye molecules, the precipitation of Cu-chelates and/or formation of pi-complexes at the electrode surface. (C) 1999 Elsevier Science Ltd. All rights reserved.