Processing and Properties of Cellular Silica Synthesized by Foaming Sol-gels

Abstract

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.

Department(s)

Materials Science and Engineering

Keywords and Phrases

Foamed Ceramics; Silica; Fabrication; Viscosity; Sols

International Standard Serial Number (ISSN)

0002-7820; 1551-2916

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1990 Wiley-Blackwell, All rights reserved.

Publication Date

01 Jan 1990

Link to Full Text

Share

 
COinS