Experimental and Theoretical Investigations on the Corrosion Inhibition action of Thiadiazole Derivatives on Carbon Steel in 1M HCl medium

Abstract

Novel thiadiazole derivatives of Schiff bases namely (E)-N-(anthracen-9-ylmethylene)-5-(4-nitrophenyl)-1,3,4-thiadiazol-2-amine (A9CNPTDA) and N-(anthracen-9(10H)-ylidene)-5-(4-nitrophenyl)-1,3,4-thiadiazol-2-amine (ANNPTDA) were synthesized, characterized and corrosion inhibition behaviour, as well as the mechanism of inhibition were investigated by different monitoring techniques like gravimetric measurements, electrochemical impedance spectroscopy, potentiodynamic polarization, quantum chemical and SEM studies. Both of the thiadiazole derivatives showed excellent corrosion inhibitor action on carbon Steel in acid medium. A9CNPTDA exhibited highest inhibition efficiency of 98.04% at 1mM concentration while ANNPTDA showed a maximum of 95.32%. In HCl medium, both derivatives obeyed Langmuir adsorption isotherm and thermodynamic parameters (Kads, ΔG0ads) were calculated. An acceptable relationship was observed between the results of quantum chemical calculations and other corrosion monitoring analysis.