Conclusions
Formamide is the first DCCA that shows the feasibility of the use of organic solvents as a means of improving the processing of metal organic derived gels. It reduces gelation, aging, drying times, the drying stress, and increases the size of gel monolith that can be made up to about 100 cm3 after drying for 2 days. This is facilitated by acid catalysis and the correct solvent volume. The acid catalysis caused rapid hydrolysis allowing a stronger gel to be formed. FTIR spectroscopy liquid cell monitoring of the sol reactions confirms the influence of HNO3 and NH2CHO on the sol reaction rates. A DCCA modified silica gel can be densified by 1000°C without devitrification, but further work on a new DCCA is needed to densify large monoliths.
Similar content being viewed by others
References
L.C. Klein and E. J. Garvey in: Ultrastructure Processing of Ceramics, Glasses and Composites, L.L. Hench and D. R. Ulrich, eds. (John Wiley and Sons 1984) in press.
J. Zarzycki in: Ultrastructure Processing of Ceramics, Glasses and Composites, L.L. Hench and D.R. Ulrich, eds. (John Wiley and Sons 1984) in press.
S. Wallace and L.L. Hench, “Metal Organic Derived 20L Gel Monoliths,” to be published in the Proceedings of the 7th Annual Conf. on Composites and Advanced Ceramic Materials, Am. Ceram. Soc.
H. Schmidt, H. Scholze and A. Kaiser, “Principles of Hydrolysis and Condensation Reactions of Alkoxysilanes,” Proceedings of 2nd International Workshop on Glasses and Glass Ceramics from Gels.
M. Prassas and L.L. Hench in: Ultrastructure Processing of Ceramics, Glasses and Composites, L.L. Hench and D. R. Ulrich, eds. (John Wiley and Sons 1984) in press.
M. Nogami and Y. Moruja, Yogyo-Kyokai-Shi 87, 34–42 (1979).
J. Phalippou, T. Woignier and J. Zarzycki in: Ultrastructure Processing of Ceramics, Glasses and Composites, L.L. Hench and D. R. Ulrich, eds. (John Wiley and Sons 1984) in press.
S.H. Wang and L.L. Hench, “Processing Variables of Sol-Gel Derived 20 Soda Silicates,” to be published in the Proceedings of the 7th Annual Conf. on Composites and Advanced Ceramic Materials, Am. Ceram. Soc.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Wallace, S., Hench, L.L. The Processing and Characterization of DCCA Modified Gel-Derived Silica. MRS Online Proceedings Library 32, 47 (1984). https://doi.org/10.1557/PROC-32-47
Published:
DOI: https://doi.org/10.1557/PROC-32-47