(1. 北京有色金属研究总院， 北京 100088;
2. 西北工业大学 凝固技术国家重点实验室， 西安 710072)
摘 要: 通过Y和Ca的同时加入获得了阻燃效果优异的Mg-3.5Y-0.8Ca阻燃镁合金， 实现了镁合金在大气条件下的无保护熔炼。 俄歇电子能谱仪和X射线衍射表面分析结果表明： Mg-3.5Y-0.8Ca阻燃镁合金在高温下暴露于大气中时，合金表面会生成一层以Y2O3为主的氧化膜； 干燥空气中， Mg-3.5Y-0.8Ca合金在773、 873和973 K下氧化时， 其氧化动力学曲线遵循立方规律； 基于高温氧化热力学分析，建立了Mg-Y合金在高温下的选择性氧化模型， 并分析Ca在Mg-Y合金选择性氧化中的第三元素效应， 即Ca元素加入Mg-Y合金后， 同时起到“吸气剂”作用和增强Y元素表面活性的作用， 因而大大降低了Y2O3发生选择性氧化所需Y含量阈值。
关键字: Mg-3.5Y-0.8Ca; 阻燃剂； 氧化特性；表面分析
Mg-3.5Y-0.8Ca alloys at high temperatures
（1. Beijing General Research Institute for Non-ferrous Metals,
Beijing 100088, China;
2. State Key Laboratory of Solidification Processing,
Northwestern Polytechnical University, Xi'an 710072, China）
Abstract: Ignition-proof magnesium alloy bearing yttrium and calcium was acquired. The alloy Mg-3.5Y-0.8Ca could be melted without any protections. Auger electron spectrometer and X-ray diffraction analysis of oxide scale reveal that the oxide film forms on the surface of Mg-3.5Y-0.8Ca alloy is mainly composed of Y2O3. Thermogravimetric measurements in dry air reveal that the oxidation dynamics curves measured at 773, 873 and 973 K follow the quartic law. Based on the oxidation thermodynamics analysis, the model of the selective oxidation for Mg-Y alloys was established, and both the selective oxidation and the third element effect of Ca lead to the formation of the film composed mainly of Y2O3 for Mg-3.5Y-0.8Ca alloy.
Key words: Mg-3.5Y-0.8Ca; ignition proof agent; oxidation characteristic; surface analysis
