温度对AZ91D镁合金初期大气腐蚀行为的影响

采用金相显微镜、扫描电镜（SEM）、能谱仪（EDS）、X-射线衍射（XRD）研究温度对AZ91D镁合金初期大气腐蚀的影响，并且分析了AZ91D镁合金在不同温度的大气环境中的腐蚀形貌和腐蚀产物。试验结果表明：镁合金在20℃大气环境中的腐蚀增重随时间变化较小，30℃大气环境中的腐蚀增重在196h后加速，腐蚀428h后镁合金在30℃大气中的腐蚀增重约为20℃的2倍。20℃和30℃大气环境中的腐蚀产物主要以胞状形态生长，胞状产物表面附着大量的针状产物。随温度升高，初期腐蚀速率提高，腐蚀产物覆盖率增加。

Influence of Temperature on Initial Atmospheric Corrosion Behavior of AZ91D Magnesium Alloy

The influence of temperature on initial atmospheric corrosion behavior of AZ91D magnesium alloy was studied by optical microscopy （OM） , scanning electron microscopy （SEM） , energy dispersion spectrum （EDS） and X-ray diffraction （XRD）. The chemical composition and appearance of the corrosion products at different temperatures in atmosphere were analyzed. The results show that the mass gain of AZ91D magnesium alloy in atmosphere increased exponentially at the initial stage. The mass gain of AZ91D at 30 ℃ was nearly double that at 20℃ after testing for 428 h. The mass gain of AZ91D increased slowly during the whole prodess of testing at 20℃. However, the mass gain of AZ91D began Lo accelerate after testing for 196 h at 30 ℃. The corrosion products at 20 ℃ or 30 ℃ mainly presented cellular appearance, and there were many needle-like corrosion products adhering to the surface of the cellular products. Both the initial corrosion rate and the coverage rate of the corrosion products increased with the rise of temperature.