Effect of Grain Boundaries on Thermal Conductivity of Silicon Carbide Ceramic at 5 to 1300 K

• Published in: Journal of the American Ceramic Society Vol. 86; no. 10; pp. 1812 - 1814
• Main Authors: Watari, Koji, Nakano, Hiromi, Sato, Kimiyasu, Urabe, Kazuyoshi, Ishizaki, Kozo, Cao, Shixun, Mori, Katsunori
• Format: Journal Article
• Language: English
• Published: Westerville, Ohio American Ceramics Society 01.10.2003; Blackwell; Wiley Subscription Services, Inc
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Chemical industry and chemicals; Exact sciences and technology; grain boundaries; phonons; silicon carbide; Structural ceramics; Technical ceramics; thermal conductivity; Thermal properties; Silicon Carbides; Temperature effect; Thermal conductivity; High temperature; Experimental study; Low temperature; Non oxide ceramics; Structural ceramic; Grain boundary
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/j.1151-2916.2003.tb03563.x

The thermal conductivity of a SiC ceramic was measured as 270 W·m−1·K−1 at room temperature. At low temperatures (T < 25 K), the decrease in the conductivity was proportional to T3 on a logarithmic scale, which indicated that the conductivity was controlled by boundaries. The calculated phonon mean free path in the ceramic increased with decreased temperature, but was limited to ∼4 μm, a length almost equal to the grain size, at temperatures below 30 K. We concluded that the thermal conductivity of the ceramic below 30 K was influenced significantly by grain boundaries and grain junctions.