AZ91D镁合金微弧氧化膜层的高温氧化行为研究

Study on High Temperature Oxidation Behavior of Micro-arc Oxidation Coating on AZ91D Alloy

在AZ91D镁合金表面采用微弧氧化技术制备了不同厚度的陶瓷膜层,研究了不同厚度陶瓷膜层的高温氧化行为,讨论了膜层厚度对膜层高温氧化行为的影响。结果表明:膜层厚度在40μm内的AZ91D镁合金微弧氧化试样,在400℃加热128 h后,随膜层厚度的增加,膜层中疏松层所占比例增加,膜层对氧的阻挡作用增强,膜层增重量降低,膜层表面颜色变化减小,膜层破坏程度减轻,膜层在高温下保持完整的时间延长,高温氧化产物主要由镁和氧组成。

The ceramic coatings with different thickness were prepared on AZ91D alloy by micro-arc oxidation technology, the high temperature oxidation behavior of coatings with different thickness was studied, the effects of thickness of ceramic coating on high temperature oxidation behavior were discussed. The results show that the ceramic coating within40 μm on AZ91D alloy is heated at 400 ℃ for 128 h, the ratio of the loose layer is increased, the blocking effect of the coating is enhanced, the mass gain in the coating and the changes of the color of the coating are reduced, the time of coating maintaining complete is increased with the increase of the coating thickness, and the oxide is mainly composed of Mg and O.