Synthesis and properties of CeB6 thermionic cathode with {001} fiber texture by reactive spark plasma sintering method

Rare earth hexaborid have attracted much attention because of their excellent properties such as low work function, high melting temperature, strength, and chemical stability [1]. Hexaboride des are of great technological significance as thermionic cathodes in electronic devices [2–3]. CeB6 is one of the rare earth borides owning high emission density with low work function and low operating temperature. CeB6 is resistant to the negative impact of carbon contamination than LaB6. Moreover, CeB6 has higher resistivity than LaB6, this means it is more suitable as direct cathode than LaB6. Hence, CeB6 is the material of choice for high current density cathode. However, in fact, because of the long sintering time and high temperature, the traditional hot pressure sintering preparation of polycrystalline CeB6 bulk causes coarse grains and low density which decrease the emission property. In this paper, we report a study on quick spark plasma sintering (SPS) method for synthesizing the polycrystalline CeB6 bulk.