镁合金在硅酸盐体系中微弧氧化膜层的性能研究

Properties of microarc oxidation coating of magnesium alloy oxidized in silicate system

利用交流微弧氧化装置对AZ91D镁合金在硅酸盐体系中进行了微弧氧化处理,并通过扫描电镜、电化学测试技术和表面性能测试仪等研究了氧化时间和电流密度对微弧氧化膜层表面形貌、厚度、耐蚀性、摩擦磨损性能和结合力的影响。结果表明:随氧化时间和电流密度的增大,镁合金微弧氧化膜层中微孔的数量减少,但微孔的直径和表面粗糙度增大。膜层厚度随氧化时间和电流密度的增加呈线性增大,但与基体的结合力明显降低。镁合金微弧氧化膜层的耐蚀性和耐磨性随氧化时间和电流密度的增大呈先增大后减小的趋势。镁合金在硅酸盐体系中微弧氧化处理的最佳工艺为氧化时间40min、电流密度0.20A/cm2。

Magnesium alloy AZ91D was processed in silicate system under different current densities for different time. The morphology, thickness, corrosion resistance, friction and wear properties and adhesion force with the matrix of the microarc oxidation coatings were observed and examined by scanning electron microscopy, electrochemical testing methods and surface performance apparatus. The results show that with the increasing of processing time and current density, the amount of micropores in the microarc oxidation coating decreases, but the size of micropore and the roughness of coating become larger. The microarc oxidation coating obtained under long processing time and high current density has a greater thickness and a lower adhesion force than that at short time and low current density. The corrosion and wear resistance of microarc oxidation coating increase firstly and then decrease with increasing of processing time and current density. The optimum processing parameters of microarc oxidation for magnesium alloy in silicate system are processing time of 40 min and current density of 0.20A/cm2.