Corrosion inhibition of Monel 400 in hydrochloric solution by some green leaves

Purpose The purpose of this study was to investigate the inhibitive action of some green leaves on Monel 400 alloy in acidic media. Design/methodology/approach Green leaves of Mespilus japonica, Ricinus communis L and Vitis vinifera were immersed in methanol solutions, separately, and filtrated after 48 h of immersion; the obtained filtrates were examined as corrosion inhibitors of Monel 400 alloy in hydrochloric acid solution (1.0M HCl). The performance of these inhibitors was evaluated using electrochemical impedance spectroscopy and potentiodynamic polarization. The effect of temperature on corrosion behavior of Monel 400 was also studied. Findings The results obtained showed that all tested inhibitors performed as good corrosion inhibitors. The inhibition process is attributed to the adsorption of the inhibitors on Monel surface. The adsorption behavior was found to follow Langmiur isotherm. The inhibition efficiencies of extracts increased with increasing the concentration of each inhibitor and deceased with increasing the temperature. Practical implication These inhibitors could have application in industries where hydrochloric solutions were used to remove the surface impurities of Monel 400. Originality/value This paper helps to find new corrosion inhibitors that are safe and eco-friendly.