ABSTRACT:
The Mentha spicata plant extract was tested as a corrosion inhibitor for mild steel in 2M H2SO4 solution by weight loss and thermometric methods. It has been found that the extract acts as an effective corrosion inhibitor for mild steel in Sulphuric acid medium. The inhibition process is attributed to the formation of an adsorbed film of inhibitor on the metal surface which protects the metal against corrosion. The inhibition efficiency (%IE) and Surface coverage (?) of M. spicata extract increased with increase in inhibitor concentration but decreased with increasing the temperature. The adsorption of plant extract constituents on the mild steel surface was discussed by Langmuir’s adsorption isotherm. The free energy value (?Gads), indicated that the adsorption of inhibitor molecules was physisorption. The surface morphology of metal plate was analyzed using scanning electron microscopy which showed the formation of protective layer on the mild steel surface. The results obtained show that M. spicata extract can be employed as an excellent corrosion inhibitor with good anticorrosion properties in 2M Sulphuric acid for mild steel.