Structural characterization of SiO2Al2O3 aerogels
| Autor: | H. Bürger, G. Holzhüter, B. Himmel, Th. Gerber, A. Olbertz |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Materials science
Small-angle X-ray scattering Supercritical drying Sintering Mineralogy Aerogel Condensed Matter Physics Electronic Optical and Magnetic Materials Amorphous solid law.invention Electron diffraction Chemical engineering Transmission electron microscopy law Materials Chemistry Ceramics and Composites Crystallization |
| Zdroj: | Journal of Non-Crystalline Solids. 186:149-158 |
| ISSN: | 0022-3093 |
| DOI: | 10.1016/0022-3093(95)00045-3 |
| Popis: | Low-density x SiO 2 -(1 - x )Al 2 O 3 aerogels with x = 0, 0.3, 0.7, 1.0 (mole fractions) were prepared by CO 2 supercritical drying of alkogels formed from Si(OMe) 4 and Al(OBu s ) 3 by hydrolytic polycondensation under different chemical conditions. The resulting aerogels were structurally characterized by X-ray scattering at small and large angles as well as by electron diffraction and transmission electron microscopy. By investigating the dependence of linear shrinkage on the heat treatment it was found that the sintering of the aerogel is influenced by the presence of Al 2 O 3 in the network. Crystallization experiments were also performed up to 1200°C. The reduced height of the first sharp diffraction peak indicates less order in the SiO 2 network of the aerogel in comparison with amorphous SiO 2 prepared by other methods. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect