Thermal conduction mechanism of aluminium nitride ceramics
- 303 Downloads
Extremely large grain size AIN ceramics were produced by HIP sintering at an ultra-high temperature of 2773 K without reducing the oxygen content in order to determine experimentally whether the factor controlling thermal conductivity is either grain boundaries or the internal structure of the grains. The room-temperature thermal conductivity of the HIPed AIN with a grain size of ∼40 μm was 155 Wm−1 K−1, and was almost equal to that of the normally sintered AIN with a grain size of 4 μm. Therefore, thermal conductivity at room temperature is independent of AIN grain size, or the number and amount of grain-boundary phase for reasonably well-sintered AIN ceramics. The calculated phonon mean free path of sintered bodies was 10–30 nm at room temperature, which is too small to compare with the AIN grain size. Consequently, it is shown that the thermal conductivity of sintered AIN is controlled by the internal structure of the grains, such as oxygen solute atoms.
KeywordsOxygen Polymer Aluminium Grain Size Thermal Conductivity
Unable to display preview. Download preview PDF.
- 4.N. Kuramoto, H. Taniguchi, Y. Numata and I. Aso, J. Ceram. Soc. Jpn 93 (1985) 517.Google Scholar
- 10.K. Ishizaki, in “Euro-ceramics, Vol. 1, Processing of Ceramics”, edited by G. D. With, R. A. Terpstra and R. Metselaar (Elsevier Applied Science, London, New York, 1989) p. 1.314.Google Scholar
- 12.K. Uehara and Y. Sakashita, in “Proceedings of the 9th HIP Seminar” (Kobe Steel Ltd, Kobe, Japan, 1989) p. 31.Google Scholar
- 13.Y. Sakashita, C. Manabe, K. Muramatsu, S. Kofune, T. Fujikawa and T. Kanda, in “Proceedings of the 2nd International Conference on Hot Isostatic Pressing — Theory and Application” (ASM International, Gaithersburg, USA, 1989) in press.Google Scholar
- 15.Idem., J. Ceram. Soc. Jpn Int. Ed. 97 (1989) 170.Google Scholar
- 16.E. Udagawa, N. Makihara, N. Kamehara and K. Niwa, in “Proceedings of the 1st Fall Meeting of the Ceramic Society of Japan”, Nagaoka, Japan (1987) p. 241.Google Scholar