Crossandra infundibuliformis Leaves as an Effective Inhibitor for Mild Steel Corrosion in 1 M HCl
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Date
2010
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Abstract
Corrosion inhibition of mild steel in 1 M HCl was investigated in the absence and presence of different concentrations
of extract of Crossandra infundibuliformis leaves. Weight loss measurements and electrochemical studies were
employed. The corrosion rate of mild steel and the inhibition efficiencies of the extract were calculated. The results
obtained show that the extract solution of the plant could serve as an effective inhibitor for the corrosion of mild steel
in HCl media. Inhibition was found to increase with increasing concentration of the plant extract. The inhibitive
actions of plant extract are discussed on the basis of adsorption of stable complex at the mild steel surface. Theoretical
fitting of different isotherms, Langmuir, Temkin, Freundlich, Frumkin, Flory-Huggins and the kinetic thermodynamic
model were tested to clarify the nature of adsorption. Polarisation curves revealed that this inhibitor act as a mixed
type inhibitor and the inhibition efficiency up to 97.41 % can be obtained. The surface analysis study confirms the
corrosion of mild steel and its inhibition by the inhibitor.