A novel fly ash bifunctional filler for epoxy coating with long-term anti-corrosion performance under harsh conditions

• Bifunctional platform with high corrosion resistance is prepared by Fe 3+ and PFOA. • Corrosion protection is provided by strong shielding and metal passivation function. • Bifunctional platform has strong resistance to extremely corrosive environments. A robust bifunctional platform (FA-PANI-Fe-F) with both shielding performance and corrosion inhibition activity was prepared and observed for its structure and morphology. During the corrosion test, Fe 2+ /Fe 3+ and perfluorinated groups effectively strengthened the shielding performance and corrosion inhibition activity of the coating. The results show that the perfluorinated group not only improved the hydrophobic performance of the functional filler but also provided effective inhibition against corrosion for the anode area. In addition, Fe 2+ /Fe 3+ resulted in the functional filler exhibiting anodic protection and cathodic inhibition properties, thereby forming a dense metal passivation film between the coating and the substrate interface. After the EIS test, the |Z| 0.01 Hz value of FPF-Fe 10% C still reached 7.91 × 10 8 Ω·cm 2 . Additionally, the FPF-Fe 10% C showed a lower cathodic corrosion trend in the SVET test, which indicated that Fe 2+ /Fe 3+ effectively inhibited the corrosion process in the cathode region. This study is expected to open new insights into the anti-corrosion inhibition process between the interior of the coating and the metal substrate, and prepare a robust bifunctional filler platform with long-term corrosion resistance.