Comparison of metal-inhibitor systems by electrochemical impedance spectroscopy

Abstract

The inhibiting effect of several organic compounds on copper corrosion in boric-borate buffer with 0.1M NaCl (pH = 9) was studied. The organic compounds 1 mM benzotriazole (BTA), 1 mM 5-methyl-benzotriazole (TTA), 1 mM potassium ethyl xantate (KEX) and the mixture [1 mM TTA+1 mM KEX], were used as inhibitors. Analysis of impedance spectra data was done by fitting an equivalent circuit to these data. The best inhibiting action was found with the mixture TTA+KEX. From the results, it can be concluded that the application of the electrochemical impedance spectroscopy to the corrosion inhibition has made possible the attainment of new information about the interaction of the inhibitors with the metallic surfaces when copper is exposed to corrosive environments.