铝锌合金在镁合金AZ91D中的扩渗机理及腐蚀性能研究  

Mechanism and Corrosion Resistance of Surface Alloying Layer on AZ91D with Aluminum and Zinc

作　　者：姚军[1] 林文光[1] 孙广平[2] 

机构地区：[1]内蒙古工业大学材料科学与工程学院,内蒙古呼和浩特010051 [2]吉林大学教育部汽车材料重点实验室,吉林长春130025

出　　处：《中国材料科技与设备》2011年第5期51-55,共5页Chinese Materials Science Technology & Equipment

摘　　要：采用包埋铝和锌的方法在镁合金AZ91D表面制备了铝-锌合金化涂层，并且利用x射线衍射、能谱分析研究了该涂层的组织和耐腐蚀性能。该涂层外层为AlMg2Zn, Mg7Zn3 和Mg17Al12 金属间化合物层；内层为Mg17Al12金属间化合物分布于α-Mg晶界。研究表明，与镁合金基体相比较在质量分数为3.5wt.% NaCl扩渗层显示出较好的耐腐蚀性能。盐雾腐蚀说明，Al-Mg-Zn合金化扩渗层对于降低腐蚀速率起到有效作用。此外，合金化扩渗层与基体的结合是冶金结合，且涂层的显微硬度显著提高。An aluminized and zinced alloying layer on AZ91D magnesium alloy was conducted by pack aluminum and zinc powder in the furnace and its microstructure characteristic and corrosion resistance were investigated. X-- ray diffraction and energy dispersive spectrum （EDS） arialysis showed that the alloying diffusion layer could be divided into： the outer layer is mainly composed of AlMg2Zn, Mg7Zn3 and Mg17Al12 intermetallic compounds zone; and the inner zone was α-Mg phase and Mg17Al12 intermetallic compounds distributed in grain boundary. It was found that the surface alloying layer displayed better corrosion resistance compared to the unpacked substrate in the continued immersion test of 3.5wt.% NaCl solution. The salt fog test indicated that the Al--Mg--Zn intermetallic compounds in the coating were an effective corrosion barrier to decrease the corrosion rate for aluminized and zinced alloying layer. In addition, the bonding between the alloying layer and the substrate was metallurgical and the microhardness of surface alloying layer increased significantly.

关 键 词：镁合金 合金化 组织 耐腐蚀性 铝 锌 

分 类 号：TG174[金属学及工艺—金属表面处理]