Accession Number : AD0288935

Title :   STUDIES OF ELECTRON TUBE MATERIALS AND THERMIONIC EMISSION PROCESSES

Corporate Author : GENERAL TELEPHONE AND ELECTRONICS LABS INC BAYSIDE N Y

Personal Author(s) : FLORIO,JOHN V. ; POLANYI,T.G.

Report Date : 30 SEP 1962

Pagination or Media Count : 1

Abstract : A comparison of the emission properties of pureNi base cathodes with cathodes containing known impurities in either the base metal or the coating permitted a more critical evaluation of the effects of the impurities on emission. The slow activation of the W-Ni base oxide cathodes and the enhancement of emission with successive high-temperature processing treatments (increased reaction between W and the oxide) are in sharp contrast to results obtained with the binder. Electrolytic activation of an oxide cathode by drawing plate current has usually been ascribed to electrolytic dissociation of the cathode coating, evaporation of oxygen, and activation by the excess Ba residue. The results obtained on a special tube with movable anodes indicate that, under electron bombardment, evaporation of Ba from the anode back to the cathode is responsible for activation. The sublimation from a Ta-base oxide cathode has been measured as a function of cathode temperature. The sublimate is predominantly atomic Ba and the sublimation rates are considerably greater than those found for the Pt, pure Ni or N4 Ni cathodes. The Ta base cathode can thus be used as a convenient controlled source of Ba atoms in the study of cathode coating activation. (Author)

Descriptors :   *ELECTRON TUBES, *OXIDE CATHODES, *THERMIONIC EMISSION, BARIUM, BARIUM COMPOUNDS, CATHODES (ELECTRON TUBES), CHEMICAL REACTIONS, COATINGS, DIODES, EVAPORATION, IMPURITIES, L BAND, MATERIALS, MOLYBDENUM, NICKEL, OXIDES, PLATINUM, SUBLIMATION, TANTALUM, THIN FILMS (STORAGE DEVICES)

Distribution Statement : APPROVED FOR PUBLIC RELEASE