A thermionic energy converter with an electrolytically etched tungsten emitter

Journal Article · Wed Aug 15 00:00:00 EDT 1990 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.346578· OSTI ID:6494068

Gubbels, G H.M.; Metselaar, R ^[1]

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1. Laboratory for Solid State Chemistry and Materials Science, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (The Netherlands)

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 ({ital I}-{ital V}) characteristics were measured. The influence of the emitter, collector, and cesium reservoir temperatures on the {ital I}-{ital 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 {degree}C, in the case of an unetched tungsten emitter a power density of 1.5 W/cm{sup 2} was found, while for an etched tungsten emitter it was 4.5 W/cm{sup 2}. 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 WO{sub 3}, from the etched tungsten emitter.

• OSTI ID: 6494068
• Journal Information: Journal of Applied Physics; (USA), Vol. 68:4; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
TUNGSTEN
THERMIONIC EMISSION
AUGER ELECTRON SPECTROSCOPY
ELECTRIC CONDUCTIVITY
ETCHING
PLASMA
SCANNING ELECTRON MICROSCOPY
SPRAYS
TEMPERATURE DEPENDENCE
WORK FUNCTIONS
X-RAY DIFFRACTION
COHERENT SCATTERING
DIFFRACTION
ELECTRICAL PROPERTIES
ELECTRON MICROSCOPY
ELECTRON SPECTROSCOPY
ELEMENTS
EMISSION
FUNCTIONS
METALS
MICROSCOPY
PHYSICAL PROPERTIES
SCATTERING
SPECTROSCOPY
SURFACE FINISHING
TRANSITION ELEMENTS
360104* - Metals & Alloys- Physical Properties