Inhibition Characteristics of Watermelon Oil on Aluminium in Acids and Saline Water

Abstract

The response of aluminium specimens immersed in saline water and 1 molar aqueous solution of acetic and sulphuric acids towards corrosion inhibitive actions of oil locally extracted from seeds of watermelon was investigated. Mirror polished aluminium specimens measuring 10-mm diameter by 20-mm length were immersed in batches of plastic beakers containing 50 ml of saline water and acid solutions with watermelon seed oil concentrations by weight of 0.0, 0.5, 1.0, 1.5 and 2.0% as inhibitors. Weight loss method was used to monitor corrosion rate of the specimens over a period of 240 hours. Results showed that reasonable corrosion and inhibition occurred in specimens immersed in solutions of sulphuric and acetic acids while weight losses in specimens immersed in saline water were very minimal and beyond detectable limits of weighing apparatus used. Statistical average reductions of 26, 1.5, 2 and 16% in corrosion rates were achieved, respectively, with the addition of 0.5, 1.0, 1.5 and 2.0% watermelon seed oil for specimens immersed in sulphuric acid, while 49, 6, 28 and 20% reductions were achieved for aluminium in acetic acid solutions. The oil was therefore more inhibitive in acetic than sulphuric acids.