微波烧结法制备含钪扩散阴极及其发射性能研究  

Preparation of Scandium Dispenser Cathode by Microwave Sintering and Its Electron Emission Property

作　　者：刘伟[1] 李俊辉 王金淑[1] 周帆 杨韵斐[1] 潘兆柳 吴浩 李世磊 Liu Wei;Li Junhui;Wang Jinshu;Zhou Fan;Yang Yunfei;Pan Zhaoliu;Wu Hao;Li Shilei(Key Laboratory of Advanced Functional Materials,Ministry of Education,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学新型功能材料教育部重点实验室,北京100124

出　　处：《稀有金属材料与工程》2020年第5期1766-1772,共7页Rare Metal Materials and Engineering

基　　金：国家高技术研究发展计划(“863”计划)(2015AA1214);国家自然科学基金(51534009);北京市教委重点项目(KZ201510005003)。

摘　　要：采用溶胶凝胶结合氢还原法制备出Sc均匀掺杂的钨粉,随后采用微波烧结法成功制备出浸渍型含钪扩散阴极。对Sc掺杂钨粉特性、Sc掺杂钨海绵基体微观结构、阴极发射性能和阴极表面活性物质分布进行了分析,结果显示:Sc以Sc2O3的形态均匀分布于平均粒径1μm的钨粉中,海绵体骨架主要由大小均匀的亚微米级准球形颗粒构成,表面孔结构良好,孔分布均匀,平均孔径在0.46μm左右,Sc2O3均匀分布于基体之中。电子发射测试结果表明,该阴极950℃b时脉冲偏离点电流密度Jdiv为137.59 A/cm2,发射斜率1.431。激活后的阴极表面Ba:Sc:O的原子比例为1.8:1:2.2,同时阴极表面存在大量的纳米粒子,对阴极发射有促进作用。Uniform scandium doped tungsten powder was prepared by sol-gel method combined with reduction process,and then the scandium doped impregnated cathode was successfully prepared by microwave sintering.The characteristics of Sc-doped tungsten powder,the microstructure of cathode sponge matrix,the emission properties,and the surface behavior of the active substance were analyzed.The result shows that the scandium doped tungsten powder has the average size of around 1μm and Sc element is uniformly distributed.The morphology of the sponge skeleton is spherical,the pore distribution is uniform,the average pore diameter is about 0.46μm,and scandium is evenly distributed in the matrix.The cathode prepared by the microwave sintering method exhibits good emission properties,e.g.,the current density of this cathode reaches 137.59 A/cm2 at 950°Cb,and the emission slope is 1.431.The atomic ratio of Ba:Sc:O on the cathode surface is 1.8:1:2.2 after activation,and a large amount of nanoparticles are present on the cathode surface,which promotes emission of the cathode.

关 键 词：钨 含钪扩散阴极 热电子发射 微波烧结 

分 类 号：O462[理学—电子物理学]