预处理对压铸镁合金微弧氧化膜的影响

微弧氧化前,用打磨和喷砂两种方法对基材进行预处理,获得两种氧化膜试样,对比了这两种试样的形貌、化学组成及耐腐蚀性能,分析了预处理方法对微弧氧化电压值的影响。结果表明:打磨后微弧氧化的电压值高于喷砂后微弧氧化;微弧氧化膜的耐蚀性能较基体大幅度提高,打磨试样的耐蚀性能较喷砂试样提高了40%左右;喷砂试样的氧化膜表面整体保留了喷砂后粗糙不平的形貌,而打磨试样的氧化膜较喷砂试样平整,微孔尺寸均匀且较喷砂试样的尺寸小;氧化膜表面的化学成分主要有O,Mg,Si,Al等,预处理对氧化膜化学成分及含量的影响不显著。

Effects of Pre-treatments on Micro-arc Oxidation Film of Die Casting Magnesium Alloy

Two different micro-arc oxidation films were prepared by blasting and polishing pretreatment before micro-arc oxidation.The morphology,chemical composition and corrosion resistance of the two films were compared,the effect of pretreatment on voltage value of micro-arc oxidation was analyzed.The results show that: the polishing samples of voltage value in the oxidation process are higher than the sandblasted specimens;The corrosion resistance of micro-arc oxidation coatings is greatly improved compared with substrate,and the corrosion resistance of polishing oxide film improves about 40% compare for blasting oxide film;The surface morphology of blasting oxide film retaines the rough topography of the sample blasting,while the polishing oxide film surface is smoother,the size of holes are smaller and more and uniform distribution compared with the blasting;The surface composition of oxide film consist of main elements of O,Mg,Si,Al,and have nothing with pretreatment methods.