Inhibition of corrosion of aluminium in alkaline medium by succinic acid in conjunction with zinc sulphate and diethylene triamine penta (Methylene phosphonic acid)

Shanmugam Rajendran, C. Thanga

Abstract

The inhibition efficiency (IE) of succinic acid (SA) in conjunction with Zn2+ and diethylene triamine penta (methylene phosphonic acid) [DTPMP] on the corrosion of aluminium in 0.01M NaOH was investigated by weight loss and electrochemical techniques. The ternary system SA (240 ppm) – Zn2+ (20 ppm) - DTPMP (20ppm) has 98% IE. IE values calculated from electrochemical polarization studies were in good agreement with those calculated from weight loss studies. ΔG Values were calculated from surface coverage values. Effect of temperature on the IE was also studied from which Ea and ΔH were computed. Surface morphology studies were done using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The inhibitors act as mixed inhibitors and obey Langmuir adsorption isotherm.