PANI-Fe2O3 composite for enhancement of active life of alkyd resin coating for corrosion protection of steel

In-situ synthesized PANI-Fe2O3 composite was incorporated into a commercial alkyd resin and developed an efficient anticorrosive coating for mild steel. Both the composite and the fabricated alkyd resin coating were systematically characterized by using FTIR, XRD, SEM, TEM, XPS, TGA, OSP, SKPM, and EDS. Corrosion-resistant characteristics of the nanocomposite coatings were evaluated by potentiodynamic polarization, impedance spectroscopy, and long-term open circuit potential measurements in 3.5% NaCl and 1 M HCl. The much-improved corrosion resistance of the PANI-Fe2O3 incorporated coating was correlated with the better barrier performance and the passivation protection offered. The higher corrosion resistance observed in the acidic medium was explained by the complimentary cathodic reaction of the conductive emeraldine-PANI to the nonconductive leuco-PANI. The fabrication method provided can be beneficial for developing eco-friendly anticorrosion ‘conducting polymer-metal oxide-alkyd resin’ coatings.