Gd掺杂CeB_6基阴极材料的制备及性能

Preparation and Properties of the CeB_6 Base Cathode Material with Gd Doping

以CeB_6和GdB_6粉末为原料,采用放电等离子烧结技术(SPS)制备了高致密的多元稀土六硼化物Gd_xCe_(1-x)B_6(x=0.0~1.0)多晶块体。系统研究了Gd掺杂对Gd_xCe_(1-x)B_6多晶块体的物相组成、力学性能、电阻率及热发射性能的影响。研究结果表明,在烧结温度为1550℃,烧结压强为50 MPa,保温5 min的工艺条件下,可获得高致密的Gd_xCe_(1-x)B_6单相块体材料。烧结块体的维氏硬度可达24.02 GPa。热电子发射性能测试结果表明,适量的Gd掺杂可以显著提高电子发射性能,其中Gd_(0.1)Ce_(0.9)B_6成分块体具有最佳的热电子发射性能,在1600℃,4 kV外加电压条件下,发射电流密度达到101.57 A·cm^(-2),零场电流密度达到21.94 A·cm^(-2),平均有效逸出功为2.34 eV,优于同一条件下GdB_6和CeB_6块体的热发射性能。

GdB6 and CeB6 were used as raw materials, and hexaborides GdxCe（1-x）B6（x=0.0-1.0） bulk materials were prepared by spark plasma sintering（SPS）. The effects of Gd doping on the phase composition, the mechanical properties, the resistivity and the thermionic emission properties of the CeB6 base material were studied. The results show that high density GdxCe（1-x）B6 single-phase block material can be obtained with the sintering parameters including the temperature 1550 ℃, the pressure 50 MPa and holding time 5 min. And the Vickers hardness of the sintered samples can reach 24.02 GPa. The thermionic emission properties results show that the proper amount of Gd doping can significantly improve the electron emission properties of bulk materials. Gd（0.1）Ce（0.9）B6 composition block has the best thermal emission properties; its emission current density is 101.57 A/cm2, the zero field current density is 21.94 A/cm^2, and the average effective work function is 2.34 eV under the applied voltage condition of 4 kV at 1600 ℃, which are better than those of GdB6 and CeB6 block samples under the same conditions.