Accession Number : AD0769108

Title :   Thermal Expansivity and Conductivity of Pure and Silicon-Alloyed Pyrocarbons,

Corporate Author : GULF GENERAL ATOMIC CO SAN DIEGO CALIF

Personal Author(s) : Price,R. J. ; Koyama,K.

Report Date : 15 OCT 1973

Pagination or Media Count : 20

Abstract : Measurements were made of the thermal expansivity (22 to 1000C) and the thermal conductivity (22 to 800C) of isotropic pyrocarbons deposited in fluidized beds and containing up to 34 wt % silicon in the form of beta-silicon carbide particles. The thermal expansivity of the pure carbons was proportional to their density, while that of the silicon-alloyed carbons decreased with increasing silicon content. The thermal conductivity of both pure and silicon-alloyed pyrocarbons increased with increasing temperature. The room-temperature thermal conductivity of the pure carbons increased with increasing apparent crystallite height (Lc), and the conductivity of the silicon-alloyed carbons was significantly lower than that of pure pyrocarbon with the same Lc. The results suggest that silicon entering substitutionally into the carbon lattice may reduce the conductivity. (Modified author abstract)

Descriptors :   (*Pyrolytic graphite, Thermal properties), (*Silicon carbides, Thermal properties), Thermal conductivity, Thermal expansion, Carbon, Solid solutions, Crystal lattices, Propane

Subject Categories : Ceramics, Refractories and Glass
      Crystallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE