June 22-27, 2014
Highly porous fibrous ceramics were fabricated by vacuum-molding the fiber slurry and sintering the dried felt. The materials comprised of a random network of ceramic fibers and air, with the pore sizes on micron scale. The effects of binder content and porosity on the microstructure and room-temperature thermal conductivity of fibrous ceramics were investigated. It was found that the room-temperature thermal conductivity increased with increasing binder content. In addition, the thermal conductivity decreased from 0.18 to 0.06 W/(m·K) when porosity increased from 73% to 90%, showing nearly a linear relationship. The high-temperature thermal conductivity in the range of 200-1200℃ for three different porosities were also investigated. The thermal conductivity increased as temperature and density increased. Furthermore, the porous ceramics were impregnated with silica aerogel to further lower the thermal conductivity. The room-temperature thermal conductivity decreased from 0.049 to 0.040 W/(m·K), and the back temperature decreased from 870℃ to 750℃ after the aerogel impregnation, showing better high-temperature insulation performance.
Jingjing Sun, Zijun Hu, Jiejie Zhuo, Xiaoyan Wang, and Chencheng Sun, "Thermal properties of highly porous fibrous ceramics" in "5th International Conference on Porous Media and Their Applications in Science, Engineering and Industry", Prof. Kambiz Vafai, University of California, Riverside; Prof. Adrian Bejan, Duke University; Prof. Akira Nakayama, Shizuoka University; Prof. Oronzio Manca, Seconda Università degli Studi Napoli Eds, ECI Symposium Series, (2014). http://dc.engconfintl.org/porous_media_V/5