Electrochemical and thermodynamic investigation of some soluble terpolymers as effective corrosion inhibitors for mild steel in 1M hydrochloric acid solution

Abstract

Three Terpolymers derived from resorcinol (R) and formaldehyde (F) and diaminoethane (TER-1), urea (TER-2) and thiourea (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 and weight loss methods. The values of activation energy (Ea) various thermodynamic parameters were calculated to describe the mechanism of adsorption. The inhibition efficiency of the synthesized inhibitors followed the order TER-3 > TER-2 > TER-1. Among the studied terpolymers, TER-3 exhibited the best inhibition efficiency (95% at 50 ppm). Potentiodynamic polarizations studies suggest that all terpolymers are mixed type inhibitors. © 2013 by ESG.