๐”– Bobbio Scriptorium
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Thermal conductivity of polycrystalline graphite

โœ Scribed by R. Taylor; K.E. Gilchrist; L.J. Poston


Publisher
Elsevier Science
Year
1968
Tongue
English
Weight
630 KB
Volume
6
Category
Article
ISSN
0008-6223

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โœฆ Synopsis


Measurements of thermal conductivity from 100 to 900ยฐK and electrical resistivity at 80ยฐK have been made on two mutually perpendicular directions of two types of anisotropic polycrystalline graphites and of two isotropic graphites of different densities. The thermal conductivity curves can be fitted using expressions calculated for thermal resistance due to boundary and isotope scattering and a relationship for Umklapp scattering derived from pyrolytic graphite. By invoking a factor to account for the reduction in conductivity due to porosity and irregular arrangement of crystallites in polycrystalline graphite, crystallite sizes values are obtained from thermal conductivity analysis. Crystallite sizes obtained from electrical resistivity measurements using the simple two band model are about Z/3 those derived from thermal conductivity and various reasons are suggested to explain the difference.


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