中文摘要：

采用水热法在Mg-3Nd-Zn-Zr合金表面制备无铬化学转化膜,研究了乙酸钠对膜层的影响.用场发射扫描电镜、X射线衍射、电化学测试方法分别研究了转化膜的形貌、相组成和耐蚀性能.结果表明,转化膜主要由球形颗粒状和层片状的Mg（OH）_2相、以及少量含Si的非晶化合物组成;适量的乙酸钠能促进球形颗粒状和层片状Mg（OH）_2发生团聚,缩小层片间隙,且对转化膜的生长速率影响小;膜层厚度可以达到约25μm,与基体结合牢固,耐蚀性得到明显提高.

英文摘要：

A chrome-free chemical conversion film for Mg-3Nd-Zn-Zr alloy by hydrothermal process was studied.The effect of CH_3COONa on the properties of the films was then examined. The surface morphology,microstructure and corrosion resistance of the films were characterized by FE-SEM,XRD and electrochemical testing method.The results show that the conversion films mainly consist of granular particles and flakes of Mg（OH）_2 phase.A few of amorphous compounds containing Si also are found in the films.Moderate CH_3COONa can promote agglomerating of granular particles and flakes of Mg（OH）_2 without affecting the growth rate of films,which shrinks the gap of flakes Mg（OH）_2,so the porosity of the conversion films is decreased.The thickness of the film which has great adhesion with the substrate can reach about 25μm,and the corrosion resistance is improved significantly.