Study on the synergistic effects of additives on the copper corrosion inhibitors

Author(s): A.Rahimi, M.Chaghazardi

The influence ofSodiumBenzoate (SB), PotassiumIodide (KI) and Thiourea (TU), on the inhibitive effect ofBenzotriazole (BT) andTolyltriazole (TT) in acidic medium (pH3) was investigated and Electrochemical Impedance Spectroscopy (EIS), Potentiodynamic Polarization andOpen Circuit Potential (OCP)methodswere used.Results showed that the inhibitive effect of BT and TT increased synergically in the presence of these additives. Fromthe values of Rct,Cdl and Rp, itwas found that the synergistic effect of additives followthe orderKI>SB>TUin their optimumconcentration.Upon addition of these addi-tives, a synergistic effect on inhibition performance of BT and TTwas observed as indicated by impedance and polarization transient curves; also it was found that theOCP shifted towardsmore positive potentials after adding these chemicals. The strong adsorption of Benzotriazole and Tolyltriazole on themetal surface, which also contributes on the corrosion inhibition of substrate have been concluded.

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