中文摘要：

采用显微红外成像技术对镁合金阳极氧化膜表面的腐蚀特性进行了研究。镁合金在7．3Wt％Na2SO4溶液中浸泡后，表面氧化层中的部分MgO逐渐转化为Mg（OH）2，进而发生溶解和脱落，使得镁合金失去保护作用。当浸泡时间达到2h时，显微红外成像结果表明阳极氧化膜中Mg（OH）2的红外吸收信号最强，Mg（OH）2的含量最多。而4h后Mg（OH）2的红外吸收信号开始减弱，Mg（OH）2开始减少，镁合金不断被腐蚀。氧化膜中另一成分Al2O3随浸泡时间的显微红外成像信息与Mg（OH）2的变化规律相同。采用电化学阻抗谱技术对阳极氧化膜的阻抗进行测试，其阻抗随时间的变化特点基本符合氧化膜腐蚀规律。本研究对于镁合金阳极氧化膜的表征具有很好的指导作用和推广应用价值。

英文摘要：

Micro-FTIR mapping technology was used to monitor the amount and distribution of Mg（OH）2 on the anodic coating of magnesium alloy which was immersed in the 7.3 Wt% Na2 SO4 solution for different time. In the solution, part of the MgO on the surface of the Mg alloy could gradually transform into Mg（OH）2 which could be detached from the Mg alloy surface and dis-solved into the solution. With immersion time of 2 h in 7. 3 Wt% Na2 SO4 solution 2h, FTIR mapping results showed that FTIR absorption signal of Mg（OH）2 was strongest and Mg（OH）2 was most on the surface of the anodic coating. After 4 hours, the content of Mg（OH）2 began to decrease, and the Mg alloy was etched gradually. The FTIR mapping results of another compo- nent Al2O3 with immersion time were almost similar to those of Mg（OH）2. The impedance of the oxide film was also analyzed using electrochemical impedance spectroscopy. It showed that the impedance changed with the immersion time and conformed to the corrosion law of the oxide coating. This research has a good guidance and application value for characterization of the anodic coating on magnesium alloy.