Corrosion Inhibition of Aluminum Alloy by 2-Aminobenzothiazole Derivatives: A Combined Experimental and Theoretical Study

Abstract

Three 2-aminobenzothiazole molecules, 6-bromobenzo[d]thiazol-2-amine (AMBT-1), 2-aminobenzo[d]thiazole-6-carbonitrile (AMBT-2), and 6-ethylbenzo[d]thiazol-2-amine (AMBT-3) were successfully synthesized and fully characterized. The compounds were investigated as corrosion inhibitors of AA7075 aluminum alloy in 3% NaCl medium at room temperature. Different techniques were employed including weight loss analysis, electrochemical techniques, and scanning electron microscopy (SEM). The influence of the concentration was examined and the mode of adsorption of these inhibitors on the metal surface was highlighted by assigning the appropriate isotherm and determining the corresponding thermodynamic parameters. Electrochemical measurements revealed that the three inhibitors have good inhibition efficiencies (IE) obtained in the order AMBT-3 (96.80%) > AMBT-2 (95.90%) > AMBT-1 (79.24%). SEM analysis revealed an adherent and stable film adsorbed on the metal surface. In addition, the experimental results were supported by DFT and molecular dynamic (MD) calculations. MD investigations showed that the inhibitors adopted a flat position thus assuring a good protection of the aluminum surface from aggressive molecules.