采用微弧氧化表面处理技术在SiCw/AZ91镁基复合材料表面制备保护性涂层。通过与AZ91镁合金对比，研究镁基复合材料的微弧氧化行为及其形貌特征，并采用电化学方法评价了微弧氧化涂层的耐腐蚀性能。结果表明，由于SiC晶须的加入影响了阻挡层的形成，使复合材料的微弧氧化行为不同于基体合金。与合金相比，复合材料在恒电流模式下进行微弧氧化的过程中电压随时间的演变趋势不够理想，而且在相同条件下镁基复合材料的起弧时间比合金要长，导致复合材料在火花放电之前发生腐蚀。SiCw/AZ91镁基复合材料在微弧氧化过程中可能会出现烧蚀现象。虽然SiC晶须会影响复合材料表面涂层的形成，微弧氧化处理仍然能够增强镁基复合材料的耐腐蚀性能，在提高其腐蚀电位的同时降低腐蚀电流。当采用恒压模式制备涂层时，涂层耐腐蚀性能随电压的提高而增强。
Protective coatings were fabricated on the surface of SiCw/AZ91 Mg matrix composite by microarc oxidation (MAO) surface treatment technique. Microarc oxidation behaviors of SiCw/AZ91 composite were investigated by comparing with AZ91 Mg alloy. The corrosion resistance enhancement of the composite after MAO treatment was also evaluated by electrochemical method. The results show that, microarc oxidation behaviors of the composite are different from those of the alloy because the presence of SiC whisker has influenced the formation of barrier film at the initial stage of MAO. Compared with the alloy, the composite doesn’t exhibit ideal voltage evolution trend during MAO, especially at the early stage of MAO. And that for the composite, the time corresponding to occurrence of dielectric breakdown is longer than that of the alloy. This will result in corrosion of the composite in the electrolyte before occurrence of sparking discharge. Nonetheless, corrosion resistance of the composite still is improved by the MAO coating. After the composite is coated by MAO, the corrosion current is decreased and the corrosion potential is increased.
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