Study on preparation and thermionic emission of nanometer rare-earth tungsten emission materials

As one of the alternatives Th-W materials, La-W thermionic emission materials appeared in recent years. Although this emission material has good emissivity, it has not been used commercially because of its poor emission stability. Properties of a material depend on composition and microstructure. In this paper, a fine grain tungsten emission material, activated with nanoscale oxide, was fabricated by freeze-drying and spark plasma sintering, which differs completely compared to the conventional process. Emphasis has been concentrated on the relationship between surface composition and electron emission performance.