Acid Extracts of Ervatamia coronaria Leaves for Corrosion Inhibition of Mild Steel

Abstract

Corrosion inhibitors for acid cleaning processes are used to restrict dissolution of the base metal and decrease acid consumption and hydrogen gas evolution. Because of the toxic nature and high cost of some chemicals currently in use, it is necessary to develop environmentally acceptable and less expensive inhibitors. Natural products can be considered as a good source for this purpose. An evaluation of the effective performance of extract of Ervatamia coronaria leaves on the corrosion inhibition of mild steel in 1 M HCl and 0.5 M H₂SO₄ at ambient temperature has been made. Conventional weight loss and electrochemical measurements were used for the evaluation. Electrochemical studies reveal that the plant extracts act as mixed type inhibitors. The Ervatamia coronaria (Nandhiyavatai) leaves extracts yielded a maximum of 98 % in acid medium. Surface coverage values were tested graphically for suitable adsorption isotherm.