Microstructure and electrical conductivity of electroless copper plating layer on magnesium alloy micro-arc oxidation coating

镁合金微弧氧化涂层上化学镀铜层的显微组织和导电性

In order to impart electrical conductivity to the magnesium alloy micro-arc oxidation(MAO)coating,the electroless copper plating was performed.Effects of plating temperature and complexing agent concentration on the properties of the electroless copper plating layers were studied by measuring their microstructure,corrosion resistance and electrical conductivity.It was found that the optimized plating temperature was 60°C,and the most suitable value of the complexing agent concentration was 30 g/L.Under this condition,a complete and dense plating layer could be obtained.The formation mechanism of the plating layer on magnesium alloy MAO coating was analyzed.A three-stage model of the plating process was proposed.The square resistance of the plated specimen was finally reduced to 0.03Ω/□after the third stage.Through electroless copper plating,the MAO coated sample obtained excellent electrical conductivity without significantly reducing its corrosion resistance.

为了赋予镁合金微弧氧化(MAO)涂层以导电特性,对MAO涂层进行化学镀铜处理。通过测试镀层的显微组织、耐蚀性和导电性,研究镀覆温度和络合剂浓度对化学镀铜层性能的影响。结果表明,最优镀覆温度为60℃,最佳络合剂浓度为30 g/L。在此条件下,可获得完整、致密的镀层。分析镀层在镁合金MAO涂层上的形成机制,提出镀覆过程的三阶段模型。镀后试样的表面方阻在经历第三阶段后降低至0.03Ω/。通过化学镀铜,MAO样品在未明显降低耐蚀性的同时获得了良好的导电性。