Mechanism of inhibition of corrosion of mild steel by polyacrylamide, phenyl phosphonate and Zn2+

Abstract

The formulation consisting of 50ppm polyacrylamide (PAA), 300ppm phenyl phosphonic acid (PPA) and 50ppm Zn2+has 95 per cent inhibition efficiency in controlling corrosion of mild steel in a neutral aqueous environment, containing 60ppm Cl—, a situation commonly encountered in cooling water systems. A discussion of mechanistic aspects of corrosion inhibition is based on the results obtained from a potentiostatic polarization study, UVvisible, FTIR and luminescence spectra. The protective film is found to be luminescent and to consist of Fe2+–PAA complex, Fe2+–PPA complex and Zn(OH)2.