AZ91镁合金表面微弧氧化膜微观结构的TEM表征  

Characterization of Microstructure of Micro-arc Oxidation Coating on AZ91 Magnesium Alloy Surface Using Transmission Electron Microscopy

作　　者：陈显明[1] 罗承萍[2] 刘江文[2] 

机构地区：[1]肇庆学院电子信息与机电工程学院,肇庆526061 [2]华南理工大学材料科学工程学院,广州510640

出　　处：《机械工程材料》2011年第2期58-62,共5页Materials For Mechanical Engineering

基　　金：广东省科技工业攻关项目(2003C103013)

摘　　要：在硅酸盐碱性电解液中,以AZ91镁合金为基体采用恒电流控制模式制备出微弧氧化陶瓷薄膜,采用透射电镜对微弧氧化膜的微观结构进行了分析,并测试了相关性能。结果表明：镁合金在以硅酸盐溶液为主的电解液中进行微弧氧化形成的产物主要是纳米晶MgO和MgAl2O4,并且形成了少量的非晶态物质和一定比例的较粗大MgO、MgAl2O4和MgSiO3晶粒,但这些粗大晶粒尺寸也在100~300 nm之间;形成的晶粒之所以如此细小主要是由于微弧氧化过程是一个快速烧结和快速冷凝的过程;制备的氧化膜在中性盐雾36 h后的腐蚀率小于0.09 g.cm-2.d-1,而显微硬度在1 000 HV以上。Micro-arc oxidation（MAO） ceramic coating was formed on the AZ91 magnesium alloy substrate in silicate alkaline electrolytic solution employing a constant-current controlled mode,and the microstructure of the MAO coating was analyzed using transmission electron microscopy.The relative properties were also tested.The results show that the products formed during the micro-arc oxidation were mainly nanocrystalline MgO and MgAl2O4 in silicate alkaline electrolytic solution,and a little amorphous substrate and some coarse grains of MgO,MgAl2O4 and MgSiO3 with the size of 100-300 nm.The formation of the fine grains was attributed to that the MAO was a fast sintering and fast cooling process.The corrosion rate of the obtained oxide layer in the neutral salt atmosphere for 36 h was less than 0.09 g·cm-2·d-1,and the microhardness was above 1 000 HV.

关 键 词：镁合金 微弧氧化膜 透射电镜 

分 类 号：TG146[一般工业技术—材料科学与工程]