中文摘要：

为了提高镁合金的耐蚀性能,采用扫描电镜（SEM）、电化学测试和盐雾试验等技术,对不同阳极氧化液中得到的镁合金AZ91D阳极氧化膜层的微观结构及其耐蚀性能进行了评价.所有工艺采用交流电源、氧化液无氟、铬和无磷,有利环境保护.先后对外加交流电压、Na2SiO3浓度、NaAlO2浓度,以及Na2SiO3和NaAlO2的协同作用对膜层腐蚀性能的影响规律进行了考察.结果表明,外加电压和氧化液组成对氧化膜的微观结构及其性能有着至关重要的影响.在碱性溶液中,NaAlO2和Na2SiO3的协同作用下,得到的阳极氧化膜的综合耐蚀性能优异,自腐蚀电流密度达到1.87×10-7A/cm^2,耐中性盐雾大于500 h（氧化膜未封孔）.

英文摘要：

To improve the corrosion resistance of magnesium alloys, anodization was applied in basic elec trolyte. The microstructures of anodic films formed in different anodizing electrolytes on cast magnesium alloy AZglD and their corrosion protection were investigated by scanning electron microscopy （SEM）, electrochemical test and salt spray test. All techniques were carried out in AC power source, and the composition of electrolytes was free of fluorine, chromium and phosphorus. The effect of applied AC potential, concentration of Na2SiO3 and NaAlO2, synergetic process of NaAlO2 and Na2SiO3 were investigated in turn. The results show that the compositions of the electrolytes play an important role in microstructures and corrosion resistance of anodic film. In the alkali electrolytes, corrosion resistance of the anodic film formed with synergetic effect of NaAlO2 and Na2SiO3 is excellent. The corrosion current density is 1.87×10-7A/cm^2 and time of anti salt spray is over 500 hours （naked anodic film, unsealing）.