Adsorption and Thermodynamics Behaviors of Ferroin [tris(1,10-phenanthroline Iron(II) Sulphate Complex] as Corrosion Inhibitor for Mild Steel in Acidic Medium

The inhibition effect of Ferroin solution [tris(1,10-phenanthroline iron(II) sulphate complex] as a corrosion inhibitor was analysed against corrosion of mild steel (MS) in 0.5 M HCl solution, by using weight loss method, linear polarization, electrochemical impedance spectroscopy and scanning electron microscopic. The weight loss study of MS samples has proved that the reagent used was an efficient corrosion inhibitor with inhibition efficiency of >90%. The mixed mode of inhibition was confirmed by electrochemical polarizations. The results of electrochemical impedance spectroscopy have shown the changes in the impedance parameters, like Rct and Cdl, which confirmed the adsorption phenomenon taking place on the MS surface. The inhibition action of the compound was assumed to occur through adsorption on the steel surface at the active centers present in the inhibitor.