Study on preparation and emission properties of nano-composite W-La2O3 material

This paper describes the preparation of nano-composite W-La,03 material by freeze-drying and spark plasma sintering (SPS). The thermionic electron emission capability and surface properties of this material have been investigated. The surface compositions and depth profiles of the prepared material were checked in situ by means of AES from 298 K to 1573 K. Nanocomposite W-La2O3 material exhibits good electron emission performance: a saturated emission current density of 1.46 A cm(-2) can be reached at 1673 K with a corresponding work function of 2.79 eV The surface analysis results showed that the good emission capability might be related to an about 10 nm surface layer contained excess La caused by diffusion of La from bulk material to the surface. (c) 2005 Elsevier B.V. All rights reserved.