目的 通过共生沉积技术将α-Al2O3微粒引入到铸造Al-Si合金微弧氧化膜中，并研究其对膜层耐蚀性的影响。方法 利用SEM和XRD分析α-Al2O3微粒对微弧氧化膜微观结构及成分的影响。通过极化曲线、交流阻抗谱及中性盐雾试验评价膜层的耐蚀性。结果表明α-Al2O3微粒复合改变了微弧氧化膜的组成及结构。微弧氧化膜呈双层结构，表面存在大量微孔，主要组成为γ-Al2O3；加入α-Al2O3微粒后，微弧氧化复合膜的表面微孔大幅减少，致密度提高，且膜层中α-Al2O3相增多。此外，α-Al2O3微粒复合改善了微弧氧化膜的耐蚀性。微弧氧化膜在3.5 wt.%NaCl溶液中的自腐蚀电流密度约为1.476×10-5 A?cm-2，多孔层电阻Rp及阻挡层电阻Rb分别为0.259KΩ?cm2及69.18 KΩ?cm2，耐盐雾试验时间为1200h。加入α-Al2O3微粒后，微弧氧化复合膜的自腐蚀电流密度仅为微弧氧化膜层的28%，Rp大幅增加至为274.5 KΩ?cm2，且Rb也上升了一个数量级，耐盐雾试验时间可达1440h。结果α-Al2O3微粒的引入可以大幅提高铸造Al-Si合金微弧氧化膜的耐蚀性。

Objective To study the effect on corrosion resistance of composite ceramic coatings were formed on Al-Si cast alloy by microarc oxidation (MAO) in electrolyte with α-Al2O3 microparticles. Methods Using SEM and XRD analysis of α-Al2O3 particles on the micro structure and composition of coating. and Through the polarization curve, ac impedance spectroscopy and neutral salt spray test evaluation of the corrosion resistance of coating. Results show that the incorporation of α-Al2O3 microparticles changed the microstructure and phase composition of microarc oxidation (MAO) coating. MAO coating had double-layer structure and was porous, what’s more the main phase composition was γ-Al2O3.and after adding α-Al2O3,the composite coating had much less porous and appeared α-Al2O3.In addition,α-Al2O3 particle also improved corrosion resistance of MAO coating. In the 3.5wt.% NaCl solution, the corrosion current density of MAO coating was 1.476×10-5 A?cm-2, Moreover the resistance of porous layer (Rp) and the resistance of barrier layer (Rb) of MAO coating were 0.259KΩ?cm2 and 69.18 KΩ?cm2 respectively, Resistant to salt spray test time was 1200 h. However, the corrosion current density of composite coating only was 28% of the MAO coating, And showed better corrosion resistance, the resistance of porous layer (Rp) of composite coating was 274.5 KΩ?cm2 and more than that of MAO coating. In addition the resistance of barrier layer (Rb) of composite coating were higher than MAO coating an order of magnitude, and resistant to salt spray test time was 1440 h. Conclusion α-Al2O3 microparticles can effectively improve the corrosion resistance of MAO coating.