Inhibitor effects of triazole derivatives on corrosion of mild steel in acidic media

Abstract

The inhibitive action of triazoles on the corrosion of mild steel has been studied through weight loss and various electrochemical techniques. Results obtained show that these organic compounds are very good inhibitors. Triazoles are able to reduce the corrosion of steel more effectively in 1M HCl than in 0·5M H₂ SO₄. Potentiodynamic polarisation studies clearly reveal the type of inhibitor. Changes in impedance parameters (the charge transfer resistance R_t and the double layer capacitance C_dl) are related to adsorption of triazoles on the metal surface, leading to the formation of a protective film which grows with increasing exposure time. The adsorption of these inhibitors on the mild steel surface in both acids obeys the Langmuir adsorption isotherm. The comparative study of corrosion inhibition of triazole derivatives indicates that the efficiency of the 4-aminotriazole is greater than that of the 4H-triazole.