放电等离子反应液相烧结制备CeB6阴极与性能研究

以氢直流电弧法制备CeH_x纳米粉末, 再采用放电等离子（SPS）反应液相烧结纳米CeH_x和微米B的混合粉末, 制备了高性能CeB₆多晶块体热阴极材料. 研究了SPS制备CeB₆的烧结反应式及反应液相烧结机制, 确定SPS烧结CeB₆的最佳工艺为： 压力50MPa, 烧结温度1500℃, 保温时间5min. 实验结果表明, SPS制备得到了高纯单相CeB6多晶块体, 纯度达到99.89％, 相对密度达到99.61％, 维氏硬度达到2051kg/mm², 抗弯强度达到254.2MPa. 样品在1600℃温度下拐点发射电流密度达到20.38A/cm², 功函数为2.42eV. 与传统制备法相比, SPS制备显著降低了CeB₆的烧结温度, 缩短了烧结时间, 提高了力学和发射性能.

Properties of CeB6 Cathode Fabricated by Spark Plasma Reactive Liquid Phase Sintering Method

CeHx nano-powders were prepared by hydrogen arc plasma method, and then the mixed powders of nano-CeH_x and micron boron were sintered by Spark Plasma Reactive Liquid Phase Sintering (SPS) method to fabricate high-properties polycrystalline bulk CeB6 cathodes. The reaction equation of sintering CeB₆ and reactive liquid phase sintering mechanism were studied. The optimum process parameters are listed as follows, pressure of 50MPa, temperature of 1500℃, and holding time of 5min. The experimental results show that the CeB₆ sintered body with purity of 99.89％ and relative density of 99.61% is single-phase of cerium hexaboride. The hardness and bend strength of the sintered CeB₆ reach 2051kg/mm² and 254.2MPa. The electron emitting density of the CeB₆ sintered by SPS is 20.38A/cm² at 1600℃, the work function is 2.42eV. In contrast to traditional preparation method, SPS method obviously reduces the sintering temperature and shortens the sintering time of CeB₆, and improves the mechanics and emission properties.