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 It’s Electron Emission Property

摘要:

本文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、钪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：钪以Sc2O3的形态均匀分布于平均粒径1 μm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0.46 μm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。

Abstract:

In this paper, uniform scandia doped tungsten powder was prepared by sol-gel method combined with reduction process, and then the scandia 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 scandia doped tungsten powder has the average size of around 1μm and Sc element was uniformly distributed. The morphology of the sponge skeleton have spherical shape, the pore distribution was uniform, the average pore diameter is about 0.46 μm, and scandia is evenly distributed in the matrix. The cathode prepared by the microwave sintering method exhibited good emission properties, e.g., the current density of this cathode reached 137.59 A/cm2 at 950 ℃b, 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 amount of nanoparticles are present on the cathode surface , which promotes emission of the cathode.