Synergistic Effect of Purpald with Tartaric Acid on the Corrosion Inhibition of Mild Steel: from Electrochemical to Theoretical Insights

The mutually corroborated electrochemical measurements and theoretical calculations were used to investigate the corrosion inhibition performances of purpald (4-amino-3-hydrazino-5-mercapto-1,2,4-triazole, AHMT) and its synergistic effect with tartaric acid (TA) on mild steel in 0.5 M H2SO4 solution. The experimental results show that the inhibition efficiency increases with the concentration of AHMT and increases further when TA exists. Density functional theory (DFT) calculations were performed to interpret the measured data and trends observed in the electrochemical studies. Furthermore, molecular dynamic simulation revealed a nearly flat configuration for molecules on metal surface with negative adsorption energies in a sequence agreed with experimental observation.