Use of <i>Rosmarinus officinalis</i> as Green Corrosion Inhibitor for Carbon Steel in Acid Medium

Abstract

The use of Rosmarinus officinalis as a corrosion inhibitor for 1018 carbon steel in 0.5 M H2SO4 has been evaluated by using weight loss, potentiodynamic polarization curves and electrochemical impedance spectroscopy techniques at 25°. Inhibitor concentrations were included within the range between 0 and 1000 ppm C using three extract solvents, namely acetone, hexane and methanol. Results have shown that Rosmarinus officinalis is a good corrosion inhibitor with its efficiency increasing with the concentration. The best efficiency was obtained with the hexanic extract. The passivating film properties of the steel were improved by the presence of flavonoids in the extract.