EN
The corrosion inhibition performances of leave extracts of Evolvulus alsinoideson (EA) X70 carbon steel in 5% HCl was investigated using weight loss and surface analysis. Weight loss measurement showed that this leave extract has high inhibiting properties for X70 steel corrosion in acidic solution and the inhibition efficiency increased with the increase in inhibitor concentration. The inhibitive action of plant extract is discussed on the basis of adsorption of stable complex at the X70 steel surface. Adsorption of EA on the X70 steel surface in 5% HCl obeys the Langmuir adsorption isotherm. Gibbs free energy of adsorption was calculated and indicated that adsorption occurred through physical and spontaneous process. Scanning electron microscopy (SEM) of the inhibitor-adsorbed steel surface affirmed the adsorption of inhibitor and improvement in the surface smoothness of the X70 steel.