添加剂对AZ91D镁合金微弧氧化膜的影响

Effects of Electrolyte Additives on the Performance of Micro-Arc Oxide Films on AZ91D Magnesium Alloy

摘要:

铝酸钠和氢氧化钠为主要组元，分别添加蒙脱石、EDTA、阿拉伯树胶的电解液对AZ91D镁合金进行微弧氧化，并用SEM、EDS、XRD和动电位极化曲线分析其微观组织结构和耐腐蚀性。结果表明，3种膜层的表面呈蜂窝状微观形貌，陶瓷氧化膜中主要存在相有MgAl2O4、MgO和Mg2SiO4。与AZ91D镁合金基体相比其耐蚀性均有不同程度提高，其中以蒙脱石添加后膜层的耐蚀效果最好

Abstract:

Micro-arc oxide (MAO) films were prepared on AZ91D magnesium alloy in an electrolyte bath of aluminate and sodium hydroxide with different additives such as montmorillonite, EDTA and arabin. The effects of additives on the chemical composition and corrosion resistance of MAO films were examined by means of SEM, EDS, XRD and potentiodynamic polarization in a 3.5% NaCl solution. The results show that the morphology of MAO films is like alveolate, and the microstructure is consisted of MgAl2O4, MgO and Mg2SiO4 phases. Compared with the untreated magnesium alloy, the MAO treated specimen exhibits higher corrosion resistance, especially for the films using montmorillonite as additive