镁合金低压恒流阳极氧化膜研究

采用环保型阳极氧化工艺,在低压恒流条件下,在镁合金AZ31表面获得了质量良好的白色氧化膜层,用SEM,XRD和XPS等分析手段,研究氧化膜层的微观形貌、相组成和化学组成,并采用动电位扫描的电化学方法考察氧化膜的耐腐蚀性能。结果表明:不同电流密度时,都可在阳极表面观察到细小电火花。制得的阳极氧化膜的主要相组成是MgO,同时含有Al2O3,Na4(AlSiO4)3(OH)等;膜层具有多孔结构,孔径较为均匀,膜层与基体结合牢固;在质量分数为3.5%的NaCl溶液中,阳极氧化的镁合金耐腐蚀性优于没有经过阳极氧化试样的耐腐蚀性。

Study on anodic films on Mg alloy obtained with applied constant current densities at low voltages

A novel white film was formed on the surface of AZ31 magnesium alloy through a new environment-friendly anodizing process with applied constant current densities at low voltages.The microstructures and phase structures of coating were studied by means of SEM,XRD and XPS.The corrosion resistance of the anodic film was investigated by dynamic potential scanning method.The results showed that a multitude of small sparks covered the entire surfaces of the samples at applied constant current densities.The structure of the anodized film was uniform and porous.The anodized film was conjoined strongly to the substrate.The films were mainly consisted of MgO,Al2O3,Na4(AlSiO4)3(OH).The corrosion resistance property of anodic films on the AZ31 magnesium surface was superior to the original samples in the 3.5 wt% NaCl solutions.