论文部分内容阅读
本文以CeH2,PrH2纳米粉和B粉为原料,在无氧环境下采用放电等离子原位反应成功制备了单相多元稀土六硼化物Pr1-xCexB6(x=0.2—0.8)阴极材料.系统研究了掺杂元素Ce对Pr1-xCexB6的物相组成、力学性能及热电子发射性能的影响.结果表明,当烧结温度为1450C,烧结压强为50MPa时可制得单相的Pr1-xCexB6多晶块体材料并且该系列样品具有良好的力学性能,维氏硬度和抗弯强度最高值分别达到了24.34GPa和226.02MPa,已达到单晶水平.热电子发射性能结果表明,随着Ce掺杂量的增加Pr1-xCexB6的发射电流密度线性增加.当阴极温度为1973K,外加电压为950V时,Pr0.4Ce0.6B6最大发射电流密度达到47.3A·cm2,该值远高于传统热压烧结法制备的发射电流密度.因此,本文该方法制备的Pr1-xCexB6多晶块体具有良好的力学性能和发射性能,作为热阴极材料将会有很好的应用前景.
In this paper, Pr1-xCexB6 (x = 0.2-0.8) single-phase polycrystalline rare earth hexaboride cathode material was successfully prepared by discharge plasma in-situ reaction using CeH2, PrH2 nanopowder and B powder as raw materials. The effect of doping Ce on the phase composition, mechanical properties and thermoelectron emission properties of Pr1-xCexB6 was investigated. The results show that when the sintering temperature is 1450C and the sintering pressure is 50MPa, single phase Pr1-xCexB6 polycrystalline Materials and the series of samples have good mechanical properties, Vickers hardness and flexural strength reached the highest value of 24.34GPa and 226.02MPa, has reached the level of single crystal.HELP performance results show that with the increase of Ce doping The emission current density of Pr1-xCexB6 increases linearly when the cathodic temperature is 1973K and the applied voltage is 950V, the maximum emission current density of Pr0.4Ce0.6B6 reaches 47.3A · cm2, which is much higher than that of the conventional hot-pressing Current density.Therefore, the Pr1-xCexB6 polycrystalline block prepared by this method has good mechanical properties and emission performance, and will be a good application prospect as a hot cathode material.