目的 在镁合金表面制备稀土铈盐转化膜，以改善镁合金的耐蚀性能。方法 利用化学转化技术在镁合金表面制备出稀土铈盐转化膜，进而采用SEM、EDAX及电化学测试技术等系统研究铈盐浓度、添加剂含量、转化时间和转化温度对转化膜形貌、成分和耐蚀性能的影响。结果 稀土铈盐转化膜呈金黄色，由Mg、Ce和O组成，表面存在网状裂纹。转化膜的耐蚀性随铈盐浓度、添加剂含量、转化温度、转化时间的增加呈现先增加后降低的变化规律。结论 稀土铈盐转化膜由Mg和Ce的氢氧化物和氧化物组成。铈盐转化膜的最佳工艺条件为：Ce(NO3)3 质量浓度10~15 g/L，H2O2添加含量25~50 mL/L，转化温度40 ℃，转化时间30 min。经稀土铈盐转化处理后，镁合金的耐蚀性能得到了明显的改善。

The work aims to improve the corrosion resistance of magnesium alloy by preparing rare earth cerate conversion coating on magnesium alloy. The rare earth cerate conversion coating was obtained the surface of magnesium alloy by virtue of chemical conversion technology. Effects of cerate concentration, additive content, conversion time and conversion temperature on coating morphology, composition and corrosion resistance of the conversion coating were studied by scanning electron microscopy (SEM), energy dispersion analyzer of X-ray (EDAX) and electrochemical test. The golden yellow cerium conversion coating consisted of Mg, Ce and O elements and microcracks were present on the surface. The corrosion resistance of coating firstly increased and then decreased with the increase of cerium salt and additive concentration, conversion time and temperature. The cerium conversion coating is composed of hydroxides and oxides of Mg and Ce elements. Optimum process conditions are as follows: Ce(NO3)3 mass concentration of 10~15 g/L, H2O2 additive content of 25~50 mL/L, conversion temperature of 40 ℃ and conversion time of 30 min. After chemical conversion treatment of cerium nitrate, the corrosion resistance of magnesium alloy is greatly improved.