A thermionic energy converter with an electrolytically etched tungsten emitter

G.H.M. Gubbels, R. Metselaar

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1 Citation (Scopus)
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Abstract

The bare work functions of etched and unetched plasma-sprayed tungsten were found to be 4.8 and 4.5 eV, respectively. The electron emission of plasma-sprayed tungsten, both etched and unetched, was measured over a wide range of temperatures in a cesium atmosphere. Work functions were derived from the saturation current densities. In the ignited mode, current-voltage (I-V) characteristics were measured. The influence of the emitter, collector, and cesium reservoir temperatures on the I-V characteristics was investigated. Barrier indexes of 2.06 and 2.30 eV were found for etched and unetched tungsten emitters, respectively. At an emitter temperature of 1400¿°C, in the case of an unetched tungsten emitter a power density of 1.5 W/cm2 was found, while for an etched tungsten emitter it was 4.5 W/cm2. This increased power density could be attributed to a lower collector work function. The lower cesiated collector work function resulted from the evaporation of oxygen, as WO3, from the etched tungsten emitter.
Original languageEnglish
Pages (from-to)1883-1889
Number of pages7
JournalJournal of Applied Physics
Volume68
Issue number4
DOIs
Publication statusPublished - 1990

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direct power generators
thermionics
tungsten
emitters
accumulators
cesium
radiant flux density
electric potential
electron emission
temperature
evaporation
current density
saturation
atmospheres
oxygen

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Gubbels, G.H.M. ; Metselaar, R. / A thermionic energy converter with an electrolytically etched tungsten emitter. In: Journal of Applied Physics. 1990 ; Vol. 68, No. 4. pp. 1883-1889.
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A thermionic energy converter with an electrolytically etched tungsten emitter. / Gubbels, G.H.M.; Metselaar, R.

In: Journal of Applied Physics, Vol. 68, No. 4, 1990, p. 1883-1889.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - A thermionic energy converter with an electrolytically etched tungsten emitter

AU - Gubbels, G.H.M.

AU - Metselaar, R.

PY - 1990

Y1 - 1990

N2 - The bare work functions of etched and unetched plasma-sprayed tungsten were found to be 4.8 and 4.5 eV, respectively. The electron emission of plasma-sprayed tungsten, both etched and unetched, was measured over a wide range of temperatures in a cesium atmosphere. Work functions were derived from the saturation current densities. In the ignited mode, current-voltage (I-V) characteristics were measured. The influence of the emitter, collector, and cesium reservoir temperatures on the I-V characteristics was investigated. Barrier indexes of 2.06 and 2.30 eV were found for etched and unetched tungsten emitters, respectively. At an emitter temperature of 1400¿°C, in the case of an unetched tungsten emitter a power density of 1.5 W/cm2 was found, while for an etched tungsten emitter it was 4.5 W/cm2. This increased power density could be attributed to a lower collector work function. The lower cesiated collector work function resulted from the evaporation of oxygen, as WO3, from the etched tungsten emitter.

AB - The bare work functions of etched and unetched plasma-sprayed tungsten were found to be 4.8 and 4.5 eV, respectively. The electron emission of plasma-sprayed tungsten, both etched and unetched, was measured over a wide range of temperatures in a cesium atmosphere. Work functions were derived from the saturation current densities. In the ignited mode, current-voltage (I-V) characteristics were measured. The influence of the emitter, collector, and cesium reservoir temperatures on the I-V characteristics was investigated. Barrier indexes of 2.06 and 2.30 eV were found for etched and unetched tungsten emitters, respectively. At an emitter temperature of 1400¿°C, in the case of an unetched tungsten emitter a power density of 1.5 W/cm2 was found, while for an etched tungsten emitter it was 4.5 W/cm2. This increased power density could be attributed to a lower collector work function. The lower cesiated collector work function resulted from the evaporation of oxygen, as WO3, from the etched tungsten emitter.

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