Effect of Grain Boundaries on Thermal Conductivity of Silicon Carbide Ceramic at 5 to 1300 K |
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| Authors: | Koji Watari Hiromi Nakano Kimiyasu Sato Kazuyoshi Urabe Kozo Ishizaki Shixun Cao Katsunori Mori |
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| Affiliation: | National Institute of Advanced Industrial Science and Technology, Nagoya 463-8560 Japan;Electron Microscope Laboratory and Department of Materials Chemistry, Ryukoku University, Seta, ôtsu 520-2194, Japan;School of Mechanical Engineering, Nagaoka University of Technology, Nagaoka 940-2188, Japan;Faculty of Engineering, Toyama University, Toyama 930-8555, Japan |
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| Abstract: | 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 T 3 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. |
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| Keywords: | silicon carbide grain boundaries thermal conductivity phonons |
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