真空硅热直接还原制备镁锂合金研究

Production of Mg-Li Alloy by Vacuum Silicothermic Reduction

提出真空硅热还原制备Mg-Li合金的新方法。热力学分析结果表明,硅热法还原制备Mg-Li合金的适宜条件为:真空度≤102Pa,还原温度≥1400 K;还原温度为1473 K时,同步液化冷凝镁锂的温度T<1062 K,同步固化冷凝镁锂的温度T<454K。在温度1200℃、真空度10～20 Pa、还原时间2 h和冷凝温度168～210℃的条件下进行实验研究,制得结晶较好的块状Mg-Li合金。X射线衍射结果表明,Mg-Li合金主要成分为Mg、Li3Mg17和Li0.92Mg4.08,残渣主要成分为Ca2SiO4。扫描电镜分析表明,Mg-Li合金呈羽毛状。X射线荧光及原子吸收分光光度计检测表明,Mg-Li合金中镁含量与锂含量分别为77.58%,8.27%。

A novel technique was developed to produce Mg-Li alloy by silicothermic reduction in vacuum.The impacts of various factors,including the pressure,reduction temperature and time,on contents and phases of the Mg-Li alloy were calculated with thermodynamics and experimentally evaluated.The condensate of Mg-Li and the slag were characterized with X-ray diffraction.The results show that the newly-developed technique is feasible to produce high quality Mg-Li alloy.Under the favorable conditions：a pressure ≤102 Pa,a reduction temperature ≥1400 K,and a reduction time for 2 h,the alloy ingot consists of Mg 77.58%（wt） and Li 8.27% of Li,in the phases of Mg,Li3Mg17,and Li0.92Mg4.08.The Ca2SiO4 dominated in the slag.At a reduction temperature of 1473 K,the synchronous liquefaction and solidification temperatures were lower than 1062 K and 454 K,respectively.