电流密度对ZK60镁合金微弧氧化膜微观结构及性能的影响

Effect of Current Density on Microstructure and Properties of ZK60 Alloy MAO Coating

以ZK60作为研究对象在优化电解液中进行微弧氧化,研究不同电流密度对ZK60镁合金微弧氧化膜层的影响,利用电压-时间曲线、扫描电镜、X射线衍射分析及全浸试验等手段对膜层的微观组织和性能等进行测试。结果表明:不同电流密度下微弧氧化过程分为阳极氧化阶段、起弧阶段和微弧氧化膜快速生长阶段,微弧氧化电压随电流密度增加而增大;电流密度为30 A/dm2时膜层微观结构均匀致密,耐蚀性最好;XRD分析表明MgO和Mg2SiO4为膜层主要构成相。

Micro-arc oxidation process was carried out in electrolyte system of Na2SiO3on ZK60 magnesium alloy. The influences of current density on microstructural characteristics of coating were investigated by voltage-time curve,SEM and XRD. Test of mass loss was conducted in 3.5% Na Cl solution to assess the resistance to corrosion. The results show that micro-arc oxidation coating growth process is divided into three stages： anodic oxidation stage,arcing stage and micro-arc oxidation stage,the voltage during MAO process increases with the increase of current density. The corrosion resistance of the coating is the best and the microstructure is uniform and dense when the current density reaches 30A/dm2. Compositional analysis indicates that Mg2 Si O4and Mg O are the main phases of ceramic coating.