镁合金微弧氧化的电解液组分研究

利用交流微弧氧化装置对AZ91D镁合金在1组分、2组分、3组分和4组分电解液中进行了微弧氧化处理,并通过电化学测试技术研究了微弧氧化处理后膜层的耐蚀性能.实验结果表明:能显著提高镁合金耐蚀性能的微弧氧化电解液,多为含NaAlO2组分的碱性溶液;电解液中添加H2O2和C4H4O6Na2等组分,可进一步提高膜层的耐蚀性.微弧氧化处理后,膜层表面光滑、均匀、致密,并由尖晶石结构的MgAl2O4相和MgO相组成.NaAlO2组分的存在,能与膜层中的MgO相在微弧氧化过程中一起烧结形成具有尖晶石结构的MgAl2O4耐蚀相,从而提高镁合金的耐蚀性能.

Electrolyte Components of Microarc Oxidation for Magnesium Alloy

AC microarc oxidation technique was used to process AZ91D magnesium alloy in electrolytes of one, two, three and four components respectively. The corrosion resistance of microarc coatings was measured elec trochemically. The results showed that the optimal electrolytes, which can greatly improve the corrosion resistance of magnesium alloy, mainly consisted of NaOH and NaAlO2 components. The corrosion resistance of microarc coatings could be increased further by the addition of H2O2 and C4H4O6Na2 components. The coating formed on AZ91D alloy was smooth, uniform and compact, and composed of MgAl2O4 and MgO phases. With the participation of MgO, NaAlO2 promoted the formation of corrosion resistant MgAl2O4 phase during the microarc oxidation process, thus enhancing the corrosion resistance of magnesium alloys.