Designing a novel GO@AAP reinforced epoxy coating for achieving the long-term corrosion protection of steel substrate

Abstract

In this study, 4-amino-antipyrine (AAP) was grafted on graphene oxide (GO) via the hydrothermal strategy (GO@AAP) to improve the corrosion resistant property of epoxy coating. Transmission electron microscope (TEM), scanning probe microscope (SPM) and Raman techniques were employed to investigate the morphology and structure of GO@AAP nanohybrid, which also effectively confirmed the successful AAP grafted on GO surface. Electrochemical and salt spray results indicated that incorporating as-synthesized GO@AAP into epoxy coating powerfully enhanced the anti-corrosion property, which was greatly consistent with the mild steel morphology after corrosion experiment. Besides, after 60 days of immersion, the |Z|0.01 Hz was 3.7 × 108 Ω·cm2, which was two order of magnitude higher than that of pure epoxy coating. Local electrochemical impedance spectroscopy (LEIS) was visually demonstrated the synergistic effect of physical shielding and corrosion inhibition of GO@AAP in 3.5 wt% NaCl solution. This work provides a new method to achieve the barrier and inhibition activities of epoxy coatings, which are suitable for heavy corrosion resistant application in harsh environment.