A thermionic energy converter with A molybdenum alumina cermet emitter

The I-V characteristics of a thermionic converter equipped with a Mo-1w/o AI203 emitter and a Mo collector were measured. The conditions were varied over a limited range without, as well as with Cs. Work functions of Mo as well as Mo-1w/o AI203 were determined. Measurements were carried out in a metal confinement research diode as well as in a glass confinement low pressure Cs diode , The results were compared with earlier measurements carried out in a electron emission microscope. They were also compared to the results obtained with another cermet material: Mo-U02. The minimum work function of a Mo-15w/o A1203 cermet as determined by electron emission microscopy was 1.2 eV. In a low pressure Cs diode we found a minimum work function for a Mo-O.5w/o Al203 cermet of 1.5 eV. When treated in a hydrogen plasma, we found a minimum workfunction of 1.3 eV for a cesiated Mo electrode, when measured in the low pressure Cs diode. The bare work function of Mo-lw/o AI203 as determined in a research diode was 4.9 eV as compared to 4.4 eV for a pure Mo collector (measured in the retarding range). The power density obtained in a research diode using a Mo-lw/o Al203 emitter was lower than the power density obtained with a Mo emitter