Insight into synergistic corrosion inhibition of thiourea and ZnCl2 on mild steel: Experimental and theoretical Approaches

Document Type : Research Article


Department of Chemistry, Federal University of Petroleum Resources, Effurun, Nigeria



Inhibition is the commonest device used to lessen metals and alloys corrosion, especially in acidic media. The synergistic effect of ZnCl2 on the corrosion inhibition efficiency of thiourea on mild steel, in 0.5 M sulfuric acid solution, has been investigated using gravimetric measurements, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and Fourier transfer infrared spectroscopy (FTIR) studies as well as density functional theory (DFT) calculations and Monte Carlo simulation. The results show that mild steel inhibition efficiency increase with increasing inhibitor concentrations, and a synergistic enhancement in inhibition efficiencies was observed when ZnCl2 was added. On the surfaces of the corroding metal, inhibitor and inhibitor + ZnCl2 adsorptions follow the Langmuir and Freundlich isotherms, respectively. SEM and FTIR examinations revealed that the metal surface had been coated with an inhibitor, preventing corrosion. The experimental results were agreeably interrelated with theoretical investigations.


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