AZ31镁合金表面锡酸盐化学转化膜的研究

Investigation on Stannate Chemical Conversion Coatings on AZ31 Magnesium Alloy

对AZ31镁合金表面采取锡酸盐化学转化处理,采用对比试验测定了转化膜在质量分数3.5%NaCl溶液中的腐蚀率,利用扫描电镜(SEM)及能谱(EDS)观察分析了转化膜的形貌和元素含量。结果表明:经锡酸盐转化后的AZ31镁合金的腐蚀率为2.65mm/a,未经转化的AZ31镁合金的腐蚀率为30.36mm/a,耐蚀性有明显提高;锡酸盐转化液pH值在3.5～12范围时对AZ31镁合金均形成了转化膜保护层。

AZ31 magnesium alloy has been adapted by stannate chemical process. The corrosion behavior and rate of specimens with and without conversion coating have been investigated by experiment of compare in 3.5wt% NaCl solution. The microstructure morphology and element contents have been analyzed by scanning electron microscopy and energy dispersive spectrometer. The results indicated that conversion film was uniform and dense covering the surface of AZ31 magnesium alloy. After chemical conversion treatment, the rate of corrosion was 2.645mm/a for AZ31 magnesium alloy in the stannate solution, the rate of corrosion was 30.36mm/a without chemical conversion treatment. The ability of corrosion resistance improved obviously. The value of pH between 3,5 and 12 has formed conversion film protection for AZ31 magnesium alloy in the stannate conversion solution.