Experimental and theoretical investigation of 3-amino-1,2,4-triazole-5-thiol as a corrosion inhibitor for carbon steel in HCl medium

The inhibition effect of 3-amino-1,2,4-triazole-5-thiol (3ATA5T) was investigated in 0.5 M HCl on carbon steel (CS) by electrochemical impedance spectroscopy and potentiodynamic measurements at various concentrations and temperatures. Results showed that the correlation between experimental (inhibition efficiencies, ΔGads, Ea) and quantum calculation parameters (dipole moment, EHOMO, ELUMO). The high inhibition efficiency was declined in terms of strongly adsorption of protonated inhibitor molecules on the metal surface and forming a protective film.

► The effect of 3-amino-1,2,4-triazole-5-thiol (3ATA5T) on carbon steel corrosion in 0.5 M HCl was investigated. ► The high inhibition efficiency was determined, which attributed to the adherent adsorption of the 3ATA5T. ► Langmuir adsorption isotherm exhibited the best fit to the experimental data. ► Quantum chemical calculations show there is a correlation between inhibitive property and molecular parameters.