Processing and Properties of Cellular Silica Synthesized by Foaming Sol-gels
A novel process for fabricating lightweight, cellular ceramics from sols is presented. the process utilizes the rapid viscosity change during gelation to stabilize the structure of a foamed silica sol. Manipulation of gel viscosity and foaming agent concentration resulted in a minimum cell size of 90 μm at 31% density and minimum density of 17% with average cell size of 400 μm. the flexural strength compared favorably with space shuttle tiles and sintered hollow glass spheres. From −50° to 150°C, the dielectric constant ranged from 1.51 to 1.55 for a 20% dense foam and was slightly dispersive, whereas the dielectric loss was comparable with fused silica.
T. Fujiu et al., "Processing and Properties of Cellular Silica Synthesized by Foaming Sol-gels," Journal of the American Ceramic Society, Wiley-Blackwell, Jan 1990.
The definitive version is available at http://dx.doi.org/10.1111/j.1151-2916.1990.tb05095.x
Materials Science and Engineering
Keywords and Phrases
Foamed Ceramics; Silica; Fabrication; Viscosity; Sols
Article - Journal
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