以氢直流电弧法制备CeHx纳米粉末, 再采用放电等离子(SPS)反应液相烧结纳米CeHx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.
CeHx nano-powders were prepared by hydrogen arc plasma method, and then the mixed powders of nano-CeHx 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.
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