Poly(2-chloroaniline) and poly(aniline-co-2-chloroaniline) films on ZnFe alloy plating

Purpose The purpose of this paper is to evaluate and compare the protective, anticorrosion behaviors and electrochemically synthesis of poly(2-chloroaniline) (PCANI) and poly(2-chloroaniline-co-aniline) P(CANI-co-ANI) films on thin zinc–iron plated carbon steel (CS). Design/methodology/approach Zinc–iron (ZnFe) alloy plating was successfully achieved on CS applying 3 mA constant current value. The PCANI and P(CANI-co-ANI) films on ZnFe-plated CS electrode were synthesized by cyclic voltammetry technique using monomer(s) containing 0.20 M sodium oxalate solution. The CS/ZnFe electrodes with and without PCANI or P(CANI-co-ANI) films were characterized using SEM and anodic linear sweep voltammograms. The anticorrosive behaviors of uncoated and coated electrodes were studied in 3.5 per cent NaCl solution by corrosion techniques which include open circuit potential measurements, the anodic polarization curves and alternative current electrochemical impedance spectroscopy (EIS) technique. Findings The protection efficiency values (E per cent) for CS/ZnFe, ZnCS/ZnFe/PCANI and CS/ZnFe/P(CANI-co-ANI) electrodes were calculated as 71.05, 84.53 and 92.79, respectively, after 168 h of immersion time. The results showed that P(CANI-co-ANI) coating on ZnFe-plated CS electrode exhibited higher corrosion resistance and provided better barrier property in comparison with PCANI coating and ZnFe alloy plating, in longer exposure time. Originality/value A number of reports on the synthesis and characterization of PANI have appeared in the literature during the past decade, but there is no such publication of PCANI. At the same time, the synthesis of PCANI onto the surface of metal alloy coating being the first of this kind, no such proceedings have been reported in the literature so far.