A Study on La2O3-Y2O3-Mo Secondary Emission Material

The substrate molybdenum doped with La2O3, Y2O3 cathode material was made by the powder metallurgy method. The secondary emission coefficients of them aterials were tested. The experimental results show that Mocathodes doped with La2O3,Y2O3 have good secondary emission properties. When the cathodes are activated, the maximal secondary emission coefficients of these cathodes are higher than 2.0 and can meet the practical requirement. The distribution of the rare earth in the interior and at surface of this kind of cathode material before and after emission was studied using Scanning Electronic Microscopic (SEM) and X -Ray Photoelectron Spectrum(XPS). The analysis results show that the rare earth is easy to gather at grain boundaries and the relevant concentration of rare earth on the surface after emission is obviously greater than that before emission .