Thermionic converter performance with oxide collectorsThermionic converters using a variety of metal oxide collector surfaces have been fabricated and tested. Both work function and power output data are presented and evaluated. Oxides of barium, strontium, zinc, tungsten and titanium have been incorporated into a variable spacing converter. Tungsten oxide was found to give the highest converter performance and to furnish oxygen for the emitter at the same time. Oxygenated emitters operate at reduced cesium pressure with an increase in electrode spacing. Electron spectroscopy for chemical analysis (ESCA) performed on several tungsten oxide collectors showed cesium penetration of the oxide layer, possibly forming a cesium tungstate bronze. Titanium oxide showed high performance but did not furnish oxygen for the emitter; strontium oxide, in the form of a sprayed layer, appeared to dissociate in the presence of cesium. Sprayed coatings of barium and zinc oxides produced collector work functions of about 1.3 eV, but had excessive series resistance. Lanthanum hexaboride, in combination with oxygen introduced through a silver tube, and cesium produced a low work function collector and better than average performance.
Document ID
19770066036
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Lieb, D. (Thermo Electron Corp. Waltham, MA, United States)
Goodale, D. (Thermo Electron Corp. Waltham, MA, United States)
Briere, T. (Thermo Electron Corp. Waltham, MA, United States)
Balestra, C. (Thermo Electron Corp. Waltham, Mass., United States)
Date Acquired
August 9, 2013
Publication Date
January 1, 1977
Subject Category
Energy Production And Conversion
Meeting Information
Meeting: Intersociety Energy Conversion Engineering Conference