Rare Earth Boride Electron Emitter Materials Fabrication and Evaluation.
Final technical rept. 10 Jul 80-9 Jul 81,
OREGON GRADUATE CENTER BEAVERTON
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Techniques were developed for routine preparation of single crystal rods of LaB6, CeB6 and PrB6 by arc float zone refining. Single crystal, oriented samples were prepared from these rods and mounted as cathodes for testing. Several mounting systems were used, and flat, pointed cone and truncated cone thermionic cathodes were studied. Pointed field emitters of LaB6100 were also investigated. Variation of thermionic emitted current density and thermal stability of materials were studied as functions of rare earth element, bulk stoichiometry and crystal orientation. Life tests were performed on several different LaB6100 cathodes. One such cathode operated for over 3000 hours at approximately 10 Asq cm emitted current density with no serious physical degradation. Surface properties of the materials were investigated by various surface analysis techniques. Author
- Inorganic Chemistry