Anticorrosive Performance of Nano-SnO₂/Polyaniline/Epoxy Composite Coatings

Nano-SnO2/polyaniline composite materials with different mass ratios were successfully prepared by in situ chemical polymerization. The as-synthesized materials were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD). And the composite coatings were prepared on the surface of 304 stainless steel (SS). The anticorrosive performance of those composite coatings was investigated by electrochemical tests and immersing experiments. The results showed that the nano-SnO2/polyaniline had superior anticorrosion performance than polyaniline. When the mass ratio of SnO2 was 4% in the mixture of SnO2 and polyaniline，the composite coating exhibited the best anticorrosive property. Based on the structure of the composite coating on 304SS surface, a reasonable equivalent circuit was established. Combining with the EIS data, the mechanism on improving the electrochemical corrosion resistance of the nano-SnO2/polyaniline/epoxy coatings was investigated.