Inhibition of the corrosion of cold rolled steel in hydrochloric acid solution by Tween-40

Purpose - The purpose of this paper is to study the inhibition effect of Tween-40 on the corrosion of cold rolled steel (CRS) in 1.0-8.0 M HCI over the temperature range of 20-50 degrees C. It also aims to make an attempt to correlate both thermodynamic parameters and kinetic parameters with the inhibition effect. Design/methodology/approach - The inhibition efficiencies of Tween-40 are investigated by weight loss and potentiodynamic polarization methods. Findings - Tween-40 acts as a good inhibitor in 1.0 M HCI, and inhibition efficiency increases with the inhibitor concentration, while it decreases with HCI concentration and temperature. The adsorption of inhibitor on the CRS surface obeys the Langmuir adsorption isotherm equation. The inhibition effect is satisfactorily explained by both thermodynamic and kinetic parameters. Polarization curves show that Tween-40 is a mixed-type inhibitor in hydrochloric acid. Originality/value - The experimental data have been treated with adsorption theory and kinetic equations successfully. Both the thermodynamic and kinetic parameters can be obtained, and used in explaining the inhibition effect satisfactorily.