Application of some oligopolymers as effective corrosion inhibitors for mild steel in 1M HCl: Gravimetric, thermodynamic and electrochemical analysis

Abstract

Three oligopolymers derived from α-Naphthol (N), formaldehyde (F) with aniline (TERP-1), para-aminobenzoic acid (TERP-2) and sulphanilic acid (TER-3) were synthesized and their inhibitive action on corrosion of mid steel in 1M HCl was studied using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, linear polarization and gravimetric methods. The values of activation energy (Ea) and some thermodynamic parameters were calculated to describe the mechanism of adsorption. The inhibition efficiency of the all three inhibitors followed the order TERP-3 > TERP-2 > TERP-1. The potentiodynamic polarization studies reveal that investigated polymers are mixed type inhibitors. Out of three polymers, TERP-3 exhibited the best inhibition efficiency (95% at 50 ppm). © 2014 The Authors.