Liangliang Xiong,Mei Yu,Yingquan Li,Xiangxin Kong,Songmei Li,Jianhua Liu
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.
A two-dimensional nanocomposite, salicylaldehyde@ZIF-8/GO (SZG), was synthesized by anchoring the ZIF-8 nanoparticles containing the inhibitor salicylaldehyde (SA) on GO nanosheets for corrosion protection of AA2024 aluminum alloy. Its stimuli-responsive release of SA under acid and Al 3+ cations conditions was proved by UV–vis. Electrochemical impedance spectroscopy demonstrated that SZG nanocomposites prominently improved the protection properties of PVB coating by enhanced passive and active protection compared with the controlled samples. The enhanced passive protection derived from the two-dimensional structure of SZG, while inhibitor SA acted the active protection. Quantum chemical calculation clearly clarified the release and inhibition mechanisms of SA.