Evaluation of corrosion resistance of citric acid secondary doped poly(o-toluidine)/titanium dioxide epoxy coatings

Epoxy resins are commonly used for corrosion protection; however, achieving sustained corrosion protection remains a significant challenge. The incorporation of corrosion-resistant fillers into epoxy resins is regarded as a straightforward and effective solution. In the present study, a citric acid secondary doped poly-o-toluidine titanium dioxide composite was prepared (PTA). The resulting composites were then mixed with epoxy resin (EP) to investigate the defense of the composite coatings against carbon steel (CS) in a corrosion-prone environment. 3 wt% PTA-EP maintained the highest impedance modulus of 9864 Ω cm² after 7 days of immersion in 3.5 wt% NaCl solution. Consequently, PTA-EP not only exhibits substantial barrier and corrosion protection properties but also generates a self-repairing passivation layer with augmented corrosion resistance. PTA-EP coatings demonstrate considerable potential for the retardation of metal corrosion.