Electrochemical Studies of Mild Steel Corrosion Inhibition in Aqueous Solution by Uncaria gambir Extract

The inhibition of the corrosion of mild steel in aqueous solutions by ethyl acetate extract of Uncaria gambir containing catechin has been studied using weight loss, potentiodynamic polarisation measurements, electrochemical impedance spectroscopy (EIS) and scanning electron microscope technology with energy dispersive X-ray spectroscopy (SEM-EDX). Inhibition was found to be highest at a concentration of 150 ppm in solutions with a pH of 5. The results obtained show that the ethyl acetate extract of U. gambir acts as a mixed-type inhibitor and could serve as an effective corrosion inhibitor of mild steel in aqueous solution.