In this paper, the dual-component silane films composed of trimethoxysilane and bis[3-(triethoxysilyl)propyl]tetrasulfide (BTESPT) were prepared on the surface of AZ31B Mg alloys. The selected trimethoxysilanes had different chain length. The results showed that the dual-component silane films could effectively enhance the corrosion resistance of Mg alloys. Moreover, with the enlarging of the chain length of trimethoxysilane, the hydrophobic property and the corrosion resistance of the dual-component silane films were enhanced. And the dual-component silane film composed of BTESPT and octadecyltrimethoxysilane (OTMS) showed the highest contact angle and the best corrosion resistance. It could be ascribed to the high density of CH 2 groups and –S–S–S–S– in the dual-component silane film, greatly improving the hydrophobicity and the anticorrosion property. Simultaneously, the substantial Si–O–Si network in the dual-component silane film also enlarged the length of the penetration paths for corrosive media, delaying the corrosion of the Mg alloy.
Octaglycidyldimethylsilyl polyhydric silsesquioxane (OG-POSS) in coordination with tetraethyl orthosilicate, tetrapropyl orthosilicate and tetrabutyl orthosilicate mixed solution was applied to the bonding of metal substrate and silicone resin thermal protective coating. The influence of OG-POSS addition on the interface of primer was systematically investigated by means of scanning electron microscope (SEM), salt spray test, thermogravimetric infrared spectroscopy (TGA-IR) and back temperature test. Results showed that the addition of OG-POSS favored the formation of a silane film of the primer, resulting in a more compact and continuous film. At the same time, the silane film had excellent corrosion resistance and adhesion, with a maximum adhesion strength of about 1.42 MPa. In addition, OG-POSS provided a unique Si-O-Si cage structure in the primer, which improved the ablation resistance of the interface layer, preventing the degradation and peeling of the coating in harsh environments.
Micro-arc oxidation (MAO) has gained widespread adoption in aluminum alloy protection due to their remarkable corrosion resistance. Nevertheless, the inherent microporous defects of MAO layer persist in exposing the substrate to corrosive damage during operational conditions. While silane-based sealing techniques have emerged as a promising solution for these defects, their practical implementation still faces critical challenges including insufficient defect-filling capacity and compromised mechanical durability. The present work employs electrochemical-assisted method that selectively generates hydroxyl/hydroxide ions at microporous defect sites within the MAO layer. Such local alkalinization conditions enable the directed assembly of silane hydrolysis products, driving interfacial adhesion-condensation reactions to achieve in situ silane film deposition with spatial selectivity. The optimized sealing system demonstrates a 50 % improvement in long-term corrosion resistance (150 MΩ·cm 2 ) compared to conventional impregnation methods, accompanied by significantly enhanced self-cleaning, wear-resistant property. This provides a solution for the multifunctional anti-corrosion, wear-resistant, self-cleaning of aluminum alloy surfaces.
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