AZ91D镁合金表面扩渗铝锌膜层改性研究  

Study of Al and Zn Alloyed Coating on Surface of AZ91D Magnesium Alloy

作　　者：毛广雷[1] 林文光[1] 

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

出　　处：《热加工工艺》2008年第8期32-34,共3页Hot Working Technology

摘　　要：采用Al、Zn固体混合粉末对AZ91D镁合金表面进行化学热扩散处理,在不同扩散温度下得到不同的热扩渗层,并对得到的渗层进行显微组织形貌、物相组成分析,并在3.5%NaCl溶液中对基体材料、扩渗试样进行了浸泡腐蚀实验。结果表明,在410、430和450℃恒温热扩散8h,扩渗层与基体材料表面之间能够形成组织均匀细密的渗层,但在不同扩渗温度形成的渗层结构不同。在410℃扩渗时,扩渗层由Mg-A1-Zn固溶体组成,随着扩渗温度的提高,扩渗层厚度增加,同时渗层开始有合金化合物生成,当扩渗温度为450℃时,则形成了稳定的表面合金层AlMg2Zn与Mg-A1-Zn固溶体层共同组成的扩渗层。同时浸泡腐蚀实验结果也表明,形成的扩渗层组织大幅度提高了AZ91D镁合金表面的耐腐蚀性。The chemical thermal-diffusion on the surface of AZ91D magnesium alloy by suing Al and Zn solid mixed powder was carried out, the thermal diffusion coating was obtained at different diffusion temperature, and its microstructure morphology, phase structure of the diffusion coating were analyzed. XRD image and corrosion resistance ability of alloying layer in 3.5% NaCl solution were investigated. The results show that the Al and Zn alloyed coating on AZ91D magnesium alloy is uniform and fine after thermal diffusion at constant temperature of 410 ℃, 430 ℃ and 450 ℃ for 8 h, but their microstructure is different. Through the microstructure observation, XRD image analysis, the alloying layer is mainly composed of Mg-Al-Zn solid solution after thermal diffusion at 410 ℃ for 8 h. The thickness of alloying layer increases and the surface creates a smaU amount of Mg-Al-Zn intermetaUic compounds at 430 ℃ for 8 h. But at 430 ℃ for 8 h, the alloyed layer is made up of Mg-Al-Zn intermetaUic compounds and Mg-Al-Zn solid solution. The corrosion resistance experiment also shows that the alloyed layer has better corrosion resistance than the AZ91D magnesium alloy.

关 键 词：AZ91D 扩渗铝锌膜 耐蚀性 

分 类 号：TG146.22[一般工业技术—材料科学与工程] O641.4[金属学及工艺—金属材料]