One-step-synthesized azole-based compounds were used as corrosion inhibitors for mild steel in 1.0 M HCl solution at 40 °C. Electrochemical impedance spectroscopy and potentiodynamic polarization showed that the triazole-based compound had the best inhibitive performance (efficiency >90%) at a concentration of 850 μM. Their inhibitive properties are attributed to their molecular structure, which features an aromatic ring with N-heterocyclic azole substituents capable of adsorbing on a metal surface to form a protective layer. The electrochemical results were supported by analyses obtained from scanning electron and atomic force microscopy, which showed improved metal topology and decrease in surface roughness by up to a factor of five, and x-ray diffraction, which revealed the extent of oxide layer formation. The adsorption of a protective inhibitor layer on the metal surface was confirmed by Raman spectroscopy, while the underlying mode and mechanism were postulated based on a Langmuir adsorption isotherm and computational studies, which showed good correlation between the inhibitive ability and the electron donating and accepting capability of the compounds.
Caldona, E. B.; Zhang, M.; Liang, G.; Hollis, T. K.; Webster, C. E.; Smith Jr, D. W.; Wipf, D. O. Corrosion Inhibition of Mild Steel in Acidic Medium by Simple Azole-Based Aromatic Compounds. J. Electroanal. Chem. 2020, 114858.
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