Physicochemical Study on the Effectiveness of Eco-Friendly Anti-Corrosion Agent on the Corrosion of Steel in H₃PO₄ Solution

抄録

The inhibitory effect of extract of Hibiscus Sabdariffa on corrosion of steel in aqueous 8 M H₃PO₄ was investigated by potentiodynamic polarization technique. The inhibition efficiency of Hibiscus extract on corrosion of steel in aqueous 8 M H₃PO₄ solution increases on increasing in concentration of the extract and decreases with a rise in temperature. Potentiodynamic polarization measurement indicates that Hibiscus acts as a corrosion inhibitor. Theoretical fitting of the different isotherms were tested to clarify the nature of adsorption. The increase in activation energy of corrosion process in the presence of the extract indicates that the extract retards the rate of corrosion of steel in 8 M H₃PO₄ solution. The structure and morphology of the extract were characterized by Fourier transform infrared spectroscopy (FTIR). Scanning electron microscopy (SEM) study confirmed the adsorption of inhibitor molecules on steel surface.