Investigation of Surface Phenomena in Thermionic Energy Conversion.
Abstract
The general goal of this project has been to enhance the understanding of surface phenomena related to thermionic energy conversion (TEC), in particular, surface properties of electrode materials which have the potential of enhancing significantly the performance of practical devices for advanced mode TEC. A variety of surface analysis techniques has been devoted to study of clean surface properties of Lanthanum Boride single crystals. Investigations of residual gas interactions with low work function emitter surfaces has been directed toward the study of 02 interactions with low work function single crystal faces of Lanthanum Boride. Measurements were made on both the clean and oxidized Lanthanum Boride surfaces using Auger electron spectroscopy (AES) and x-ray photoelectron spectroscopy (XPS) and quadrupole mass spectrometry (QMS) for analysis of the desorbing molecular species. The nature of the surface oxide species were correlated with thermal evaporation characteristics. The coadsorption of Zirconium and oxygen onto Tungsten causes a lowering of the work function of the (100) crystal plane from 4.7 to 2.6 eV. The resulting surface is remarkably stable and practical application as a cathode for fine-focussed beam applications.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1986
- Accession Number
- ADA174916
Entities
People
- P. R. Davis