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采用真空固体粉末热扩渗法,对AZ91D镁合金表面实施Al-Zn及Al-Zn-Nd共渗处理。对扩散合金层进行显微组织形貌和物相组成分析,并在3.5%NaCl溶液中测量镁合金基体及其扩渗试样的耐腐蚀性能。结果表明,在385℃下恒温热扩散10 h,能在试样表面获得一定厚度的连续均匀的渗层,且Al-Zn-Nd共渗层组织比Al-Zn共渗层组织更加细小致密;Al-Zn共渗的膜层主要由Mg_(17)Al_(12)、Al_5Mg_(11)Zn_4和α-Mg三相构成,而Al-Zn-Nd共渗的膜层主要由Mg_(17)Al_(12)、Al_5Mg_(11)Zn_4、NdAl_3和α-Mg四相构成;扩渗处理明显改善了AZ91D镁合金的耐蚀性,且Al-Zn-Nd共渗试样的耐蚀性优于Al-Zn共渗试样。
Al-Zn and Al-Zn-Nd osmosis were carried out on AZ91D magnesium alloy by vacuum solid powder thermal diffusion method. The microstructure and phase composition of the diffusion alloy layer were analyzed, and the corrosion resistance of the magnesium alloy matrix and its expanded sample was measured in 3.5% NaCl solution. The results show that the uniform diffusion layer with a certain thickness can be obtained on the sample surface by thermal diffusion at 385 ℃ for 10 h, and the microstructure of Al-Zn-Nd co-diffusion layer is more compact and compact than that of Al-Zn co-diffusion layer. The Al-Zn co-infiltrated film is mainly composed of Mg 17 Al 12, Al 5 Mg 11 Zn 4 and α-Mg three phases, while the Al-Zn-Nd co-infiltrated film mainly consists of Mg 17 Al 1 O 3, (12), Al_5Mg_ (11) Zn_4, NdAl_3 and α-Mg. The corrosion resistance of AZ91D magnesium alloy was obviously improved by the infiltration treatment, and the corrosion resistance of Al-Zn- -Zn osmosis sample.