镁合金无铬微弧氧化新工艺  

Chromium-Free Micro-Arc Oxidation Process for Magnesium Alloy

作　　者：周玲伶[1] 易丹青[1] 邓姝皓[1] 王斌[1] 

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083

出　　处：《材料保护》2006年第1期20-24,共5页Materials Protection

基　　金：2004年中俄国际合作项目(2004-07-20)

摘　　要：利用正交试验对MB2镁合金无铬、磷、镁微弧氧化成膜工艺进行了研究,同时利用表面分析技术,分析了氧化膜层的显微硬度、截面形貌和相结构,采用动电位扫描法考察了氧化膜的耐腐蚀性能。研究的最佳工艺条件为:30g/LKOH,45g/LAl(OH)3,2g/LK2SiO3,2g/L添加剂M,电流密度铬65mA/cm2,温度45℃。该微弧氧化新工艺能在镁合金上形成银灰色的氧化膜层,其显微硬度值及耐腐蚀性远优于传统含铬工艺DOW17所形成的膜层;微弧氧化膜主要由MgO,MgAl2O4,Al2O3组成,具有多孔结构,孔径较为均匀,分为内外两层,外层为疏松层,内层为与基体结合牢固的致密层;在成膜过程中,电解液的铝盐浓度和微弧氧化电流密度是影响性能的主要因素。A new micro-arc oxidation process for MB2 magnesium alloy was studied using orthogonal test. The micro-hardness of the resulting ceramic coating was measured, while its microstructure and phase structure were studied by means of scanning electron microscopy and X-ray diffraction. Moreover, the corrosion resistance of the oxide coating was investigated making use of dynamic potential scanning method. The results showed that the titled oxidation film was silver-gray and had much higher microhardness and better corrosion resistance than the micro-arc oxidation film prepared using traditional DOW17 process. The titled ceramic film, mainly composed of MgO, MgAl_2O_4, and Al_2O_3, had uniform and porous structure and could be classified into loose top layer and compact inner layer strongly adhered to the substrate. Moreover, the properties of the ceramic film were closely dependent on the current density and the concentration of the aluminum ions in the electrolyte solution.

关 键 词：微弧氧化 镁合金 耐蚀性 

分 类 号：TG174.451[金属学及工艺—金属表面处理]