Characterization of the Protective Surface Films Formed on Molten AZ91D Magnesium Alloy in SO_2/Air Atmospheres in a Sealed Furnace

作     者：Xianfei Wang Shoumei Xiong 

作者机构：Department of Mechanical EngineeringTsinghua University State Key Laboratory of Automotive Safety and EnergyTsinghua University 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2014年第30卷第4期

页      面：353-358页

核心收录：

学科分类：080503[工学-材料加工工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：supported by the Specialized Research Fund for the Doctoral Program of Higher Education under Grant No.20090002110029 the High Technology Research and Development Program of China under Grant No.2009AA03Z114 the MOST(Ministry of Science and Technology)of China under Grant No.2010DFA72760 

主　　题：Magnesium alloy S02 Sealed furnace Gas protection Surface film 

摘      要：Surface films that formed on molten AZ91D magnesium alloy in S02/air cover gases at 680 ℃ in a sealed furnace were characterized by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction and Auger electron spectroscopy. It is revealed that the film formed on molten AZ91D alloy surface in cover gas with high air content can prevent the molten AZ91D alloy from oxidation and ignition. The surface film contained three elements, namely magnesium, oxygen and sulfur, and was mainly composed of MgO and MgS. The properties of the film depended on air content in the cover gas and holding time. Thermodynamic calculation showed that MgSO4 was the stable phase, and it was concluded that the formation of MgS04 was important for the formation of the protective surface film in S02/air atmospheres.