Corrosion protective properties of epoxy coating containing tetraaniline modified nano-α-Fe2O3

In this study, a self-healing epoxy coating containing tetraaniline modified alpha-Fe2O3 (TAFe) was prepared for corrosion protection of Q235 steel. The TAFe particles were synthesized using bio-inspired catechol chemistry and the evaluation of the corrosion resistant benefits of TAFe as additive in the epoxy coating were conducted. The time-dependent corrosion protective ability of the epoxy composite coating containing TAFe applied on Q235 carbon steel were characterized by electrochemical techniques such as EIS and LEIM. Characterization of corrosion layer was done by SEM and XRD after removing coatings after 70 days of immersion in 3.5 wt% NaCl solution. Findings of corrosion measurements confirmed the existence of a small amount TAFe (0.7 wt%) resulted in improvement of corrosion protective properties of steel during corrosion process compared with neat epoxy coating and the coating with 0.7 wt% non-modified Fe2O3. Moreover, surface techniques showed compact passivated iron oxide layer beneath the coatings and presence of different metallic oxide phases for coatings. The corrosion protective enhancement of composite coating could be ascribed to electroactive function of tetraaniline layer on alpha-Fe2O3.