Corrosion Inhibition and Adsorption Process of 3-Amino-5-Mercapto-1,2,4-Triazole on Aluminium Alloy : Experimental and Theoretical Studies

The corrosion inhibition effect of 3-amino-5-mercapto-1,2,4-triazole (AMT) on AA2024 aluminium alloy in 3.5 wt.% NaCl solution was investigated, and the corrosion inhibition mechanism was revealed. The influence of AMT concentration on the corrosion inhibition performance was evaluated by potentiodynamic polarization curve and electrochemical impedance spectroscopy (EIS). Surface morphology analysis and surface-enhanced Raman scattering (SERS) spectra were used to study the adsorption process and corrosion inhibition mechanism of AMT on the alloy surface. Polarization curve and EIS results show that when the AMT concentration was 1.5 g/L, the corrosion current density (icorr) was the lowest and the resistance of adsorption film (Rf) was the largest, illustrating the highest corrosion inhibition efficiency. Moreover, the adsorption kinetics process of AMT was revealed by SERS measurement, and a positive correlation between the SERS intensity and Rf values of AMT after different immersion time was achieved. It indicates that the efficient adsorption of corrosion inhibitors significantly enhanced the corrosion inhibition performance. Density functional theory (DFT) was performed to determine the relationship between the corrosion inhibition property of AMT and the molecular structure, and the adsorption process was confirmed by molecular dynamics simulation to give further insight into the reactivity of AMT on aluminium alloy surface