Modified salicylaldehyde@ZIF-8/graphene oxide for enhancing epoxy coating corrosion protection property on AA2024-T3

Salicylaldehyde@ZIF-8/graphene oxide (SZG) nanosheets were fabricated by anchoring salicylaldehyde@ZIF-8 nanoparticles on graphene oxide. SZG nanosheets were modified by amino silane 3-aminopropyltriethoxysilane (f-SZG) to improve the compatibility with epoxy coating. Sedimentation test showed the excellent dispersion stability of f-SZG in resin epoxy even after standing for 480 h. The cross-sectional microstructure of coatings implied the strong f-SZG/coating matrix interface by transforming the cleavage fracture to the ductile. Additionally, the stimuli-responsive release to H + and Al 3+ ions of f-SZG is maintained after the silanization. Compared with other samples, f-SZG0.5 epoxy coatings show the optimal long-term corrosion protection property with the lowest reduction rate of |Z| 0.01Hz (13.6%) after 480 h immersion and the intact surface after 27d salt spray test due to the stronger interfaces of f-SZG/epoxy matrix and coating/substrate, the proper content (0.5 wt.%) and the enhanced cross-linked density of coating.