Thermal Conductivity of ß-Si3N4: I, Effects of Various Microstructural Factors |
| |
Authors: | Mikito Kitayama,&dagger ,Kiyoshi Hirao,Motohiro Toriyama,Shuzo Kanzaki |
| |
Affiliation: | Synergy Ceramics Laboratory, Fine Ceramics Research Association, Nagoya, Aichi 463-8687, Japan;National Industrial Research Institute of Nagoya, Nagoya, Aichi 463-8687, Japan |
| |
Abstract: | Calculations based on a simple modified Wiener's model for thermal conductivity of a composite material predict that the thermal conductivity of ß-Si3N4 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-Si3N4 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-Si3N4. |
| |
Keywords: | |
|
|