Electrochemical and molecular dynamics simulation studies on the corrosion inhibition of aluminum in molar hydrochloric acid using some imidazole derivatives

The corrosion inhibition and adsorption characteristics of three selected imidazole derivatives namely, 2-amino-4,5-imidazoledicarbonitril (AID), 5-amino-4-imidazolecarboxamide (AIC) and imidazole (IM) on aluminum in 1.0 M HCl was investigated at 25 °C. Measurements were carried out under various experimental conditions using chemical (weight loss), and electrochemical (Tafel polarization and impedance) methods. Molecular dynamics (MD) method and density functional theory were also applied here for theoretical study. Results obtained showed that inhibition efficiency of these compounds increases with increase in their concentrations due to the formation of a surface film on the aluminum surface. Adsorption energy as well as hydrogen bond length calculations showed that AID was the best corrosion inhibitor among the tested imidazole derivatives. Polarization measurements reveal that the selected imidazole derivatives function mainly as cathodic-type inhibitors. Physisorption, followed by chemisorption was proposed as the mechanism for the inhibition process. Adsorption via H-bond formation was also considered here. Results obtained from theoretical study were found to confirm experimental findings.