Pore structures and microstructures of silica gel monoliths at different stages of sintering
- Battelle Columbus Div., OH (USA)
The pore structures and microstructures of silica gel monoliths derived from the polycondensation of tetramethoxysilane (TMOS) in basic pH were characterized after various stages of sintering, using N{sub 2} gas adsorption-desorption, mercury porosimetry, and TEM. Gels dried by supercritical drying, i.e., aerogels and gels dried slowly in air have different pore structures and sinter with contrasting results when heat-treated under identical conditions. The air-dried gels do not sinter to full density and exhibit bloating on heating to high temperatures (1,100{degree}C), whereas under the same condition aerogels sinter to dense, transparent glass without bloating. Transmission electron microscopy shows that the microstructure of gels is composed of 5- to 10-nm primary spherical particles which clustered to form large (100 nm) spherical aggregates loosely bound to each other. In aerogels, two types of porosity exit: macroporosity and ultraporosity.
- OSTI ID:
- 5964522
- Journal Information:
- Advanced Ceramic Materials; (USA), Journal Name: Advanced Ceramic Materials; (USA) Vol. 3:5; ISSN 0883-5551; ISSN ACEME
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
ADSORBENTS
CRYSTAL STRUCTURE
DATA
ELECTRON MICROSCOPY
EXPERIMENTAL DATA
FABRICATION
INFORMATION
MEASURING INSTRUMENTS
MEASURING METHODS
MICROSCOPY
MICROSTRUCTURE
NUMERICAL DATA
PH VALUE
POROSIMETERS
POROSITY
SILICA GEL
SINTERING
TRANSMISSION ELECTRON MICROSCOPY