CORROSION PROTECTION OF MILD STEEL AND ALUMINIUM IN 0.1M AND 1M HCL ACID SOLUTIONS USING PTEROCARPUS OSUN.

The inhibition effect of Pterocarpus osun on the corrosion of mild steel and aluminium in acidic medium was studied using gravimetric techniques. Weight loss measurements were determined on metal coupons in 0.1M and 1M HCl acid within the immersion time of 24-h for 5 consecutive days. Inhibition efficiency was determined by comparing the corrosion rates of mild steel and aluminium in 0.1M and 1M HCl in the presence and absence of additives. The trend of inhibition efficiency was used to propose the mechanism of inhibition. It was found that the plant extract act as inhibitor for acid-induced corrosion of mild steel and aluminium in 0.1M and 1M HCl. Inhibition efficiency of 94.5% and 94.9% were obtained for P. osun for aluminium in 0.1M and 1M HCl and 98.9%and 96.9% for mild steel in 0.1M and 1M HCl respectively. The inhibition efficiency was found to increase with increase in inhibitor concentrations. The adsorption of the inhibitor obeyed Langmuir Adsorption Isotherm. Based on the findings, P. osun stem extract is highly recommended as an alternative to synthetic, toxic chemical inhibitors.