Comprehensive evaluation of anti-corrosion capacity of electroactive polyaniline for steels

Abstract

Purpose This study aims to present the fabrication of the two-layer system, coating it on steel surface and evaluating the system’s anti-corrosion performance using the ASTM Standard Salt-Spray Test: B117 and the technique of Electrochemical Impedance Spectroscopy (EIS). Design/methodology/approach A synthesized electroactive polyaniline (PANi) was utilized in this study to make a PANi-based primer, with which a two-layer coating system was fabricated by overlaying the primer with a polyurethane top-coat. Findings In the Salt-Spray test, the two-layer PANi/polyurethane system exhibited higher corrosion resistance than the two-layer control epoxy/polyurethane system. In particular, the PANi/polyurethane system tended to mitigate the production of rust on substrate surface and demonstrated higher delamination resistance. The EIS analysis confirmed the high corrosion resistance and delamination resistance of the two-layer PANi/polyurethane system based on parameters obtained using the best-fit equivalent circuits. Practical implications The demonstrated anti-corrosion capacity of this new PANi/polyurethane system laid a solid base for industrial applications. Originality/value This novel coating system is expected to achieve improved corrosion protection for steels than the conventional zinc-rich three-layer coatings.