Ultraviolet Aging Resistance and Corrosion Protection Performance of Silane-modified CeO2/Epoxy Composite Coatings
Aluminum-lithium alloys are critical aerospace structural materials but suffer localized corrosion in chloride environments, necessitating protective coatings that also resist ultraviolet degradation. Conventional epoxy coatings are brittle, prone to microcracking, and photodegrade under UV radiation, leading to chalking, discoloration, and loss of barrier properties. This study synthesizes sheet-like CeO2 nanoparticles via reverse precipitation and functionalizes them with vinyl triethoxysilane (VTEO) and γ-aminopropyl triethoxysilane (KH550) to enhance interfacial compatibility and dispersion in an epoxy matrix. The resulting VTEO−CeO2/Epoxy and KH550−CeO2/Epoxy composite coatings are systematically characterized using FT-IR, XRD, and TEM, confirming successful silane grafting. UV-Vis and fluorescence spectroscopy reveal that modified CeO2 absorbs UV radiation more strongly and converts it to harmless heat, delaying photoxidative degradation of aromatic ether and CH3−C bonds in the epoxy. After 168 h of UV accelerated aging, the VTEO−CeO2/Epoxy coating exhibits the lowest corrosion current density (3.175×10−7 A/cm2) and larger capacitive arc radius, indicating superior and stable corrosion resistance. Contact angle tests show minimal hydrophilicity change after aging. The self-healing mechanism involves Ce3+ reacting with water and oxygen at damage sites to form insoluble CeO2 and Ce(OH)3, blocking micropores and inhibiting corrosive media ingress. This work provides a viable strategy for multifunctional epoxy coatings with integrated UV shielding, corrosion inhibition, and autonomous self-healing for aerospace applications.