镁合金微弧氧化配方的优化及膜层耐蚀性能评价

在以氟化钠、甘油及硅酸钠作为稳定剂的电解液中采用恒电流密度对AZ31B镁合金进行微弧氧化处理。通过4因素3水平的正交实验，确定了电解液中以上3种稳定剂的适宜含量分别为2g/L、10ml／L、6g/L。研究了各种辅助成分如铝酸盐、氢氧化物等对微弧氧化过程及陶瓷膜层性能的影响，结果发现氢氧化钾的加入有利于火花的产生，但易于引起尖端放电现象，应严格控制其加入量；同时它还会使膜层的颜色从灰色逐渐转变为白色，显著提高膜层的耐蚀性。动点位极化曲线及电化学交流阻抗测试表明，微弧氧化处理后的镁合金耐蚀性显著提高

Electrolyte formula optimization of micro-arc oxidation for magnesium alloys and evaluation of film corrosion resistance

AZ31B magnesium alloys were treated by micro-arc oxidization under a constant current density in a kind of solution containing sodium fluoride, glycerin, sodium silicate used as stabilizers. The electrolyte solution was optimized by orthogonal test, and the suitable concentration of the three kinds of stabilizers mentioned above are 2 g/L, (10 mL/L,) 6 (g/L) respectively. Auxiliary ingredients such as aluminate, alkali metals hydroxide etc. were respectively added into the solution and their influences on oxidization process and film properties were studied. The results show that potassium hydroxide is beneficial to producing spark on the electrode surface, but too high potassium hydroxide content results in point discharge. Therefore, its content should be controlled strictly. The corrosion resistance of the film was improved considerably and the film color was changed from gray to white as adding potassium hydroxide into the solution. Zeta potential curves and electrochemical AC impedence test demonstrate that micro-arc oxidization improves the corrosion resistance of Mg alloys greatly.