The roles of mercapto, benzene and methyl groups in the corrosion inhibition of imidazoles on copper: I. Experimental characterization

The electrochemical behaviour and long-term immersion tests of copper were studied in 3 wt.% NaCI solution, with and without addition of imidazole (ImiH), benzimidazole (BimH) and its methyl and mercapto derivatives (1-methyl-imidazole (ImiMe), 2-mercapto-1-methyl-imidazole (SH-ImiMe) and 2-mercaptobenzimidazole (SH-BimH)). The polarization resistance of inhibitors at 1mM concentration differs markedly and displays the following trend: SH-BimH > SH-ImiMe > BimiH> lmiH > ImiMe. These inhibitors act as mixed inhibitors with a stronger effect on the anodic side. X-ray photoelectron analysis showed that the differences in inhibition efficiency are related to differences in composition and structure of the protective layer formed. (C) 2015 Elsevier Ltd. All rights reserved.