Corrosion inhibition of Q235 steel by epoxy coatings containing FG@ZIF-8

In this study, ZIF-8 modified fluorinated graphene composite (FG@ZIF-8) was innovatively prepared and used as a novel functional filler to improve the anticorrosion performance of epoxy coating on Q235 carbon steel. The morphology and structure of FG@ZIF-8 composites were characterized by scanning electron microscopy (SEM), x-ray powder diffractometer (XRD), Fourier transform infrared spectrometer (FT-IR), and x-ray photoelectron spectroscopy (XPS) tests. The results showed that the structure and morphology of the composites largely depended on the composition ratio of FG and ZIF-8. The mechanical properties and corrosion resistance of FG@ZIF-8 modified coatings were also investigated. The unique two-dimensional sheet structure and insulation of FG in the FG@ZIF-8 filler can not only inhibit the penetration of corrosive media but also discourage electron migration effectively on the interface of coating/matrix during the electrochemical reaction. Meanwhile, the chemical cross-linking between the amine groups in ZIF-8 and the epoxy group increases the degree of densification of the coatings. Besides, the 2-methylimidazole from the dissolution of ZIF-8 on FG@ZIF-8 will also inhibit the corrosion reaction. These advantages endow the FG@ZIF-8 modified epoxy coatings an excellent long-term corrosion resistance. Our findings may inspire the development of new graphene-based materials with superior protective properties for metallic materials.