La_2O_3-B_4C系反应合成LaB_6粉末  

SYNTHESIS OF LaB_6 POWDER BY REACTION IN La_2O_3-B_4C SYSTEM

作　　者：郑树起[1] 闵光辉[1] 邹增大[1] 王效志[1] 韩建德[1] 

机构地区：[1]山东大学材料科学与工程学院,济南250061

出　　处：《金属学报》2001年第4期419-422,共4页Acta Metallurgica Sinica

基　　金：国家科技部科技型中小企业创新基金19993703021411;山东省科委国际合作基金970008;山东省科委高新技术基金GX

摘　　要：系统研究了利用 Ｌａ２Ｏ３和 Ｂ４Ｃ粉制备 ＬａＢ６粉末的反应合成工艺 Ｌａ２Ｏ３－Ｂ４Ｃ系反应热力学分析表明反应产物的气体分压对 ＬａＢ６的形成有重要影响，减小气体分压可以明显降低 ＬａＢ６的合成温度，结合 ＤＴＡ 测定结果，确定了 ＬａＢ６粉末的合成温度．利用Ｘ射线衍射分析了不同温度和保温时间条件下所生成粉末的相组成，并分别用扫描电镜和化学分析方法分析了所生成 ＬａＢ６粉末的颗粒尺寸、形貌及纯度实验结果表明， Ｌａ２Ｏ３－Ｂ４Ｃ系制备 ＬａＢ６粉末的优化工艺是真空度 １３３ Ｐａ，１６７３ Ｋ保温２．５ ｈ，所合成的ＬａＢ６粉末颗粒比较规整，大多呈近似圆球形，平均直径３μｍ，纯度达９８．２％．The process to synthesize LaB6 powder from La2O3-B4C system was investigated systematically in this paper. Thermodynamic analysis shows that partial pressure of resultant gas plays an important role in the formation of LaB6, powder, and the synthetic temperature decreases notably by reducing the partial pressure, which implies the effective process can be used through high vacuum or high rate of removing gas. Combined the result of DTA analysis, the synthetic process was determined. The phase compositions of the products achieved at different temperatures and different holding times were analyzed by X-ray diffraction, and powder morphology and purity were analyzed by scanning electronic microscope and chemistry analysis separately. The best process conditions to fabricate LaB6 powder from La2O3-B4C system are 133 Pa vacuum, 2.5 holding time and heating temperature of 1673 K, the purity of powders is 98.2%, and the particles consisting of powder have regular shape and average diameter of 3 mum.

关 键 词：LA2O3 B4C 反应合成 LaB6 粉末冶金 

分 类 号：TF123[冶金工程—粉末冶金]