Electrochemical evaluation of corrosion protection performance of epoxy/polyaniline-imidazole modified ZnO nanocomposite coating on mild steel

In this research, ZnO nanoparticles modified with imidazole in O-xylene solution and characterized with Fourier transform infrared FTIR spectroscopy. Then, polyaniline-ZnO unmodified and imidazole modified nanocomposites were synthesized via in-situ emulsion polymerization method. The synthesized nanocomposites were characterized by FTIR and scanning electron microscopy SEM. The anti-corrosion behavior of the epoxy coating in the presence of unmodified ZnO, imidazole modified ZnO, polyaniline-ZnO unmodified and imidazole modified were studied in NaCl 3.5 wt solution at 65 ℃ for 100 h by electrochemical impedance spectroscopy EIS. The coating resistance Rcoat of epoxy coating containing unmodified ZnO, imidazole modified ZnO, polyaniline/ unmodified ZnO and polyaniline/ imidazole modified ZnO after 100 h immersion in saline electrolyte found to be 7.2×104 , 1.3×105 , 2.3×105 and 1.7×107 Ω cm2, respectively. It can be seen that polyaniline/ imidazole modified ZnO nanocomposite exhibited higher corrosion resistance and provided better barrier properties against ingress of corrosive electrolyte.