Accession Number:

AD0296577

Title:

THERMIONIC EMITTER MATERIAL PROPERTIES

Descriptive Note:

Technical summary rept. 15 Sep 1961-15 Sep 1962

Corporate Author:

GENERAL ELECTRIC CO PLEASANTON CA

Report Date:

1962-10-15

Pagination or Media Count:

224.0

Abstract:

U and Th bearing carbides, EuB6 and YB6 were studied to determine how these materials would react in the thermal and chemical environments associated with thermionic applications. Some of the data obtained includes Thermal shock resistance of the U bearing carbides is, very probably, inadequate for applications which require that the fuel emitter retain structural integrity under thermal cycling andor severe temperature gradient conditions. Thermophysical properties, thermal conductivity, electrical resistivity, and emissivresponding oxide materials and approach properties exhibited by metallic materials. Vapor pressure properties of the rare earth borides indicate an upper temperature limit in the neighborhood of 1400 C. Work functions of bulk carbides generally fall slightly below that of W. Cs compatibility tests showed the very marked sensitivity of carbon-rich carbide materials to Cs attack in time periods less than 500 hours. TY OF CARBIDE MATERIALS ARE SUPERIOR TO CORRESPONDING OXIDE MATERIALS AND APPROACH PROPERTIES EXHIBITED BY METALLIC MATERIALS. Vapor pressure properties of the rare earth borides indicate an upper temperature limit in the neighborhood of 1400 C. Work functions of bulk carbides generally fall slightly below that of W. Cs compatibility tests showed the very marked sensitivity of carbon-rich carbide materials to Cs attack in time periods less than 500 hours. Boride materials, on the other hand, appear resistant to Cs attack.

Subject Categories:

  • Electrical and Electronic Equipment
  • Radiofrequency Wave Propagation

Distribution Statement:

APPROVED FOR PUBLIC RELEASE