Abstract
A study is made of the properties of cermets as electrode materials for thermionic energy converters. For thermodynamic reasons it is expected that all cermets composed of pure Mo and refractory oxides have the same bare work function. From data on the work function of Mo in an oxygen atmosphere this bare work function is estimated to be F=4.9 eV (at T=1400¿°C). Experimentally, the bare work function of Al2O3-Mo cermets was found to be F=4.5 eV, independent of the relative amounts of Al2O3 and Mo. The cesiated work function of the Al2O3-Mo cermets was found to be 0.15 eV lower than the cesiated work function of pure Mo. The bare work function of Mo3Al was found to be F=4.0 eV. The cesiated work function of Mo3Al at collector temperature conditions was 0.3 eV lower than the cesiated work function of pure Mo. The electrical power density of a diode with an Al2O3-Mo cermet emitter was 0.4 W/cm2 at 1300¿°C. The barrier index at this temperature was 2.36 V. The high barrier index is attributed to a high plasma voltage drop Vd=0.91 V.
| Original language | English |
|---|---|
| Pages (from-to) | 5856-5865 |
| Number of pages | 10 |
| Journal | Journal of Applied Physics |
| Volume | 68 |
| Issue number | 11 |
| DOIs | |
| Publication status | Published - 1990 |