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Thermal Conductivity of ß‐Si3N4: I, Effects of Various Microstructural Factors
Author(s) -
Kitayama Mikito,
Hirao Kiyoshi,
Toriyama Motohiro,
Kanzaki Shuzo
Publication year - 1999
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.1151-2916.1999.tb02209.x
Subject(s) - thermal conductivity , materials science , grain size , grain boundary , conductivity , composite material , range (aeronautics) , thermal , nanometre , mineralogy , crystal (programming language) , composite number , condensed matter physics , thermodynamics , microstructure , chemistry , physics , computer science , programming language
Calculations based on a simple modified Wiener's model for thermal conductivity of a composite material predict that the thermal conductivity of ß‐Si 3 N 4 decreases quickly as the grain‐boundary film thickness increases within a range of a few tenths of a nanometer and also that it initially increases steeply with increased grain size, then reaches almost constant values. Because of the faceted nature of the ß‐Si 3 N 4 crystal, the “average” grain‐boundary film thickness is much greater than that in equilibrium. The present study demonstrates both theoretically and experimentally that grain growth alone cannot improve the thermal conductivity of ß‐Si 3 N 4 .