Development of Nanocrystalline LaB₆ Electron Emitters Processed Using Arc Thermal Plasma Route.

Present article discusses the role of plasma parameters on the morphology of nanocrystalline powders of lanthanum hexaboride (LaB6) synthesized by arc plasma gas-phase condensation method. The nanocrystalline powders so obtained were used to fabricate pellet-shaped cathodes of 5 mm diameter and thickness of 1 mm. Moreover, thermal plasma plume was used for sintering the cathodes and achieve desired densification. Prior to fabrication of cathodes, the synthesized powders of LaB6 were characterized using X-ray diffraction, Raman spectroscopy, and transmission electron microscopy to investigate phase purity and morphological properties. Finally, an indigenously developed thermionic emission experimental set-up was used to record thermionic emission current obtained from LaB6 cathode at different temperatures. Richardson Dushman equation was used to find out the work function of the cathode under investigation. [ABSTRACT FROM AUTHOR]