中文摘要：

采用微弧氧化与溶胶凝胶技术在AZ31B镁合金表面制备微弧氧化．溶胶凝胶复合膜层，并于干、湿热交替盐雾腐蚀环境下，对复合膜层的耐蚀性进行研究。结果表明，随腐蚀时间的延长，复合膜层宏观表面出现白色斑点，且斑点数量逐渐增多。微观形貌分析表明，试样原始复合膜层表面存在一定数量的微裂纹及孔洞，随干、湿热交替盐雾腐蚀的进行，复合膜层表面局部应力状态发生变化，膜层表面微裂纹及孔洞减少、减小，裂纹边缘处复合膜层有轻微剥落现象。在干、湿热交替腐蚀环境中，复合膜层划格实验评级结果均为0级，膜基结合状态良好；电化学分析表明，在腐蚀实验过程中腐蚀电位未发生明显改变，均保持在约-1．43V，复合膜层具有良好的耐蚀性。关键字：镁合金微弧氧化溶胶凝胶干、湿热交替耐蚀性中图分类号：TG174．31文献标识码：A文章编号：1005—4357（2013）05．0435—06

英文摘要：

Abstract： A composite coating was prepared by means of micro-arc oxidation （MAO） and sol-gel technique on a magnesium alloy, the coating consisted of a micro-arc oxidation （MAO） sub-layer and sol-gel top-layer. The corrosion resistance of the composite coating was examined by cyclic heat-NaC1 solution spray/dry test, while the free corrosion potential of the coated alloy was mea- sured in Na2C1 solution. Then the surface topography and adhesion of the composite coating were characterized by SEM with EDS, and cross cut test respectively. The results show that white spots appeared on the coating surface due to cyclic corrosion test and the number of spots increased with time. The adhesion of composite coatings is good. The coating exhibits a free corrosion potential about -1.43 V, and a rather good adhesion to the substrate. It is observed that there exist many mi- cro-cracks and holes on the coating surface, however the number and size of which reduced with the increase of cyclic corrosion time; and a few corrosion pits can be observed until 720 h corro- sion test. It follows that the applied sol-gel permeated into and then sealed the cracks and holes on the coating, thus enhanced the protectiveness of the later. Key words, magnesium alloy, micro-arc oxidation, sol-gel, heat-spray/dry cyclic, corrosion resistance