不同电解液体系中高纯镁表面微弧氧化膜的组织与性能

Microstructure and Properties of Micro-Arc Oxidization Coatings on Surface of High Purity Magnesium Prepared in Different Electrolyte Systems

在硅酸盐、铝酸盐、硅酸盐与铝酸盐复合3种电解液体系中对纯镁表面进行微弧氧化处理,通过扫描电镜观察、能谱分析、X射线衍射分析和电化学测试等方法研究了微弧氧化膜的组织及性能。结果表明:硅酸盐体系中得到的微弧氧化膜最厚,其厚度为34.54μm,组织相对致密均匀,主要由MgO和Mg2SiO4构成;复合体系中得到的微弧氧化膜的表面粗糙度最小,为0.19μm,组织致密均匀,主要由MgO、Mg2SiO4和MgAl2O4构成;铝酸盐体系中得到的微弧氧化膜组织的致密性最差,主要由MgO和MgAl2O4构成;硅酸盐体系中得到的微弧氧化膜耐蚀性最好,其自腐蚀电流密度比基体的小一个数量级。

The surface of pure magnesium was treated by micro-arc oxidation in three electrolyte systems of silicate system,aluminate system,silicate and aluminate composite system.The microstructure and properties of micro-arc oxidation coatings were studied by scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),X-ray diffraction(XRD)and electrochemical testing.The results show that the micro-arc oxidation coating obtained in the silicate system had the thickest thickness of 34.54μm,the structure was relatively dense and uniform,and the coating was mainly composed of MgO and Mg2SiO4.The micro-arc oxidation coating obtained in the composite electrolyte system was composed of MgO,Mg2SiO4and MgAl2O4,and had the lowest surface roughness of 0.19μm and a dense and uniform structure.The micro-arc oxidation coating obtained in the aluminate system was also composed of MgO and Mg2SiO4,and had the worst compactness in three electrolyte systems.The coating obtained in the silicate system had the best corrosion resistance,whose free corrosion current density was one order of magnitude less than that of magnesium substrate.