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Ambipolar Diffusion Contribution to High‐Temperature Thermal Conductivity of Titanium Carbide
Author(s) -
BETHIN JAMES,
WILLIAMS WENDELL S.
Publication year - 1977
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1977.tb15526.x
Subject(s) - ambipolar diffusion , condensed matter physics , thermal conductivity , scattering , materials science , thermal conduction , electron , phonon scattering , diffusion , conductivity , wiedemann–franz law , phonon , chemistry , thermodynamics , physics , composite material , optics , quantum mechanics
The odd thermal conductivity behavior of transition metal carbides– K increasing with increasing T –has been interpreted as resulting from the strong scattering of electrons by carbon vacancies and polar optical phonons and from the strong scattering of phonons by vacancies and conduction electrons. These scattering processes have been used in a Callaway analysis to fit the thermal conductivity of TiC from the liquid He temperature to 1000 K; however, at the highest temperatures a residual contribution to K was noted which increased with increasing T. An analysis of the Lorenz function has indicated that this contribution is electronic. The present work indicates, using a theory modified for semimetals, that the additional conductivity may be ambipolar diffusion (electron‐hole migration and recombination).