WSi_2/MoSi_2复合粉末材料的机械合金化合成

Sythesis of WSi_2/MoSi_2 Powders by Mechanical Alloying

通过机械合金化和热处理工艺成功地制备了MoSi2 +5 0 % (摩尔分数x)WSi2 复合粉末材料 ,利用X射线衍射手段分析了相的形成过程 ,并从热力学和球磨能量角度比较了MoSi2 和WSi2 相生成的难易程度。球磨 40h后在高于 10 0 0℃热处理可获得 (Mo ,W )Si2 合金 ;因G0(MoSi2 ) <G0(WSi2 ) ,WSi2 相较MoSi2 难生成 ,其所需球磨能量分别为 12 0 2 40kJ/g和 30 .0 6

MoSi 2+50 mol% WSi 2 powders were synthesized by means of mechanical alloying and heat treatment. Formation process of phases was characterized by X ray diffraction. The difficult degree of formation of MoSi 2 and WSi 2 phases was compared in thermodynamics and milling energy. The results show that (Mo,W)Si 2 alloy can be attained by milling for 40 h followed by heat treatment at more than 1000℃. WSi 2 is more difficult to be synthesized than MoSi 2 because of the free energy of MoSi 2 is smaller. The milling energies required for formation of MoSi 2 and WSi 2 are 30 060 kJ/g and 120.240 kJ/g, respectively.