Study on Preparation and Thermionic Emission of Nanometer Rare-earth Tungsten Emission Materials

摘要

1. During the course of heating, La, O existed in the body of material in the form of La_2O_3 molecular diffuse to the surface and form a La, O segregation layer about 10nm depth from the surface at 1573K. 2. An excess La active layer was formed at high temperature, which may do good to the electron emission. 3. The zero-field current density of nanometer La-W material is 2.52 Acm-~2 at 1773K and the average effective work function at 1523K～1773K is about 2.916eV.