A thermionic energy converter with A molybdenum alumina cermet emitter

G.H.M. Gubbels, L.R. Wolff, R. Metselaar

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review


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 .
Original languageEnglish
Title of host publicationProceedings of the 23rd Intersociety Energy Conversion Engineering Conference : 1988 IECEC, Denver, Colorado
EditorsD. Yogi Goswami
Place of PublicationNew York, N.Y.
PublisherAmerican Society of Mechanical Engineers
Publication statusPublished - 1988


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