HFC-134a为基的混合气体保护下的熔态AZ91D合金保护膜特征  

Characterization of Surface Films Formed on Molten AZ91D Magnesium Alloy Protected by HFC-134a Mixtures

作　　者：刘晓龙[1] 熊守美[1] 

机构地区：[1]清华大学机械工程系清华-东洋镁铝合金成形技术研究开发中心清华大学先进成形制造重点实验室,北京100084

出　　处：《稀有金属材料与工程》2006年第9期1396-1399,共4页Rare Metal Materials and Engineering

基　　金：清华-东洋铝合金成形技术研究开发中心研究项目及新世纪优秀人才支持计划资助

摘　　要：研究了以HFC-134a气体为基的混合气体的保护效果,形成的保护膜形貌,结构及成分;分析了各种元素在保护膜中所起的作用。实验研究表明:保护膜由MgO和MgF2混合生成,厚度一般在0.1μm～0.6μm,且保护膜在厚度方向上成分均匀;在保护膜和基体之间存在大量MgF2的聚集颗粒,这些颗粒在表面呈凹陷状。Molten magnesium oxidizes rapidly during casting and handling process, hydrofluorocarbon gas HFC-134a （1, 1, 1, 2-tetrafluoroethane） mixed with carrier gas can be used to protect molten magnesium. In this article, the microstructure and composition of the surface film formed in controlled atmosphere were studied; the contribution of different elements of cover gas to the surface films was annalyzed. Results showed that the film contains MgO and MgF2 only, AES depth profiling and SEM observation indicated the film thickness to be in the range 0.1 μm-0.6 μm, and the composition of the film was uniform in depth. Spots containing magnesium fluoride formed on the interface between the oxide film and bulk magnesium, which correspond to the concave areas from the surface observation by SEM.

关 键 词：HFC-134A 气体 保护 保护膜 镁 

分 类 号：TG174.4[金属学及工艺—金属表面处理]