Accession Number : AD0645854

Title :   THERMOEMISSIVITY CHARACTERISTICS OF TRANSIENT METALS AND THEIR COMPOUNDS,

Corporate Author : FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Samsonov,G. V. ; Paderno,Yu. B. ; Fomenko,V. S.

Report Date : 04 OCT 1966

Pagination or Media Count : 14

Abstract : A discussion is given of the connection of the thermoemissive characteristics of transitional metals, their alloys and compounds with non-metals (boron, carbon, silicon and nitrogen) with the electronic structure of both the metal and non-metal. Dependences of the work function of metals, as well as of carbides, borides, nitrides and silicides, on the position of the elements in the periodic system are presented. Cases are considered of alloys of d-transitional metals, transitional metals with non-transitional (having outer s-and p-electrons), transitional metals with non-metals (boron, carbon, silicon, nitrogen). Proceeding from the results of the discussion, the conclusion may be drawn that the work function of the electrons substantially depends on the nature of filling of p - d electron states of metal atoms and on the degree of their stability. The value of the work function is, in addition, determined by the degree of non-filling of the electron states of transitional metals and ionization potential of the metalloid atom. The maximum values of the work function should belong to systems with completely or half filled stable states. The work function of electrons from metalloid refractory compounds is lowered as a result of a lesser degree of coupling of electrons with the cores of metal and metalloid atoms. This property in conjunction with the very high melting points permits creation of effective thermocathodes on their base. (Author)

Descriptors :   (*CATHODES(ELECTRON TUBES), MATERIALS), (*THERMIONIC EMISSION, TRANSITION METALS), (*TRANSITION METALS, *WORK FUNCTIONS), ALLOYS, BORIDES, CARBIDES, SILICIDES, NITRIDES, ATOMIC ORBITALS, STABILITY, IONIZATION POTENTIALS, REFRACTORY MATERIALS, USSR

Subject Categories : Electrical and Electronic Equipment
      Ceramics, Refractories and Glass
      Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE