Preparation and performance study of micro-arc oxidation/silane composite film layer

Aluminium and its alloys have low density and excellent electrical and thermal conductivity. However, aluminium is a highly reactive element, which significantly reduces its performance. Micro-arc oxidation (MAO) technology has garnered significant attention due to its unique advantages. In this study, a MAO coating was prepared on the surface of 7050 aluminium alloy as the substrate. To further optimise the coating’s performance, a CeCin-modified MAO/silane composite coating was prepared by adding cerium cinnamate (CeCin). When the CeCin addition was 1.5 g/l, the coating’s corrosion resistance reached its optimal level. Using the MAO coating with a CeCin addition of 1.5 g/l as the base sample, micro-arc oxidation-silane composite coatings (MAO-S) and micro-arc oxidation-modified silane composite coatings (MAO-MS) containing modified nano-gadolinium₂O₃ particles were prepared via silane treatment. The results showed that both composite coatings effectively sealed the MAO coating, while the addition of modified nano-Gd₂O₃ particles significantly enhanced the cross-linking strength of the silane network. After soaking in a 3.5 wt.% NaCl solution for 40 days, the MAO-MS coating maintained its structural integrity, demonstrating its excellent long-term corrosion resistance.