On the corrosion inhibition of iron in hydrochloric acid solutions, Part I: Electrochemical DC and AC studies

AbstractThe inhibitive action of 4-methyl pyrazole (4MP) against the corrosion of iron (99.9999%) in solutions of hydrochloric acid has been studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). At inhibitor concentration range (10−3–10−2 M) in 1.0M acid, the results showed that 4MP suppressed mainly the anodic processes of iron corrosion in 1.0M HCl by adsorption on the iron surface according to Temkin adsorption isotherm. Both potentiodynamic and EIS measurements reveal that 4MP inhibits the iron corrosion in 1.0M HCl and that the efficiency increases with increasing inhibitor concentration. Data obtained from EIS were analyzed to model the corrosion inhibition process through an equivalent circuit