亚微米级压制型钪钨阴极粉末的研究

Preparation of Submicron-sized Scandia Doped Tungsten Powders and Reduction Process

偏钨酸铵、硝酸钪、硝酸钡、硝酸钙和硝酸铝液液混合,采用喷雾干燥法结合两步氢气还原成功制备出含有"411"铝酸盐的亚微米尺寸钪钨阴极粉末.利用X射线衍射仪(XRD)、扫描电镜(SEM)、能谱(EDS)和激光粒度分析仪对还原前后粉末的物相组成﹑形貌﹑粒度进行分析.实验结果显示:还原后的压制型钪钨阴极粉末呈亚微米准球形结构,粉末粒度分布集中,平均粒径在400 nm左右,且各种元素分布均匀.采用程序升温还原(TPR)对掺杂粉末的还原机理进行了研究与讨论.

Sub-micrometer sized scandia, barium, calcium and aluminum co-doped tungsten powders had been prepared by spray drying method combined with two-step hydrogen reduction. The powders morphology, elements distribution, particle size distribution and phase transformation process of reduction were characterized by scanning electron microscope （SEM）, laser diffraction particle size analyzer, energy dispersive spectrometer （EDS） and X-ray diffraction （XRD）, respectively. The experimental results show that the morphology of the processor powders prepared by spray drying have spherical shape, and the obtained co-doped tungsten powders have the average size of around 400 nm and elements distribute evenly in the powders. The reduction mechanism of decrease in the co-doped tungsten powders particle size has been discussed by temperature program reduction （TPR） in this paper.