Methanolic Extract of Salvia Officinalis plant as a green inhibitor for the corrosion of carbon steel in 1 M HCl

The corrosion inhibition properties of methanolic extract of Salvia Officinalis (MESO) on carbon steel in hydrochloric acid (1 M HCl) solution has been examined and characterized by weight loss, Tafel polarization and electrochemical impedance spectroscopy (EIS) methods. These methods were complemented with SEM and EDX examinations of the electrode surface. The experimental results reveal that the inhibitor has a good inhibiting effect on the carbon steel in 1 M HCl solution. The protection efficiency increases with increasing inhibitor concentration, but the temperature decrease the effect on the inhibition efficiency of MESO. The adsorption of MESO is found to obey the Langmuir adsorption isotherm. Thermodynamic data show that the adsorption mechanism of MESO on carbon steel surface in 1 M HCl solution is probably electrostatic-adsorption. Potentiodynamic polarization studies have shown that MESO acts as a mixed type of inhibitor.