Evaluation of anticorrosion properties of Chrysophyllum albidum leaves extract for mild steel protection in acidic media

Abstract

The inhibition efficiency of Chrysophyllum albidum extract in controlling corrosion of mild steel in 1 M HCl has been evaluated by weight loss, potentiodynamic polarization and electrochemical impedance techniques at 303 K. The effect of immersion time and temperature on inhibition efficiency of the extract was also studied. Inhibition was found to increase with increasing concentration of the extract but decrease with increasing time and temperature. Data from electrochemical measurements suggest that the extract functioned by adsorption of the organic matter on the metal/corrodent interface, inhibiting both the anodic and cathodic half reactions of the corrosion process. The increase in concentration of the inhibitor causes an increase in the activation energy and a decrease in the exponential factor k. The plant extracts follow Langmuir adsorption isotherm. Moreover, the process of adsorption is spontaneous, stable and considered to be physical adsorption. The thermodynamic properties recorded suggest that the process of film formation is higher than the destruction of the metal surface and that the adsorption process is exothermic.