The Differences between the Direct and Sol-Gel Syntheses of Silicon-Contained Calcium Phosphates


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Comparison of two experimental techniques of silicon-contained and/or silica-substituted calcium phosphate preparation from Ca(NO3)2·4H2O, NH4H2PO4, fumed silica and aqueous solution of NH4OH was performed. The first technique was a traditional one, in which the final product was synthesized in an aqueous solution by the well-known sol-gel process, followed by phase separation, washing off, drying and high-temperature sintering. An environmentally friendly direct preparation route was the second technique, in which the initial chemicals were mixed in the necessary proportions inside a crucible, followed by a high-temperature sintering of the entire mixture. The sintered powders were analyzed by the standard measurement techniques. Intentional variations from the stoichiometry within ±10% of the amounts of the mixed chemicals were employed to compare the vulnerability of both preparation techniques to random fluctuations of the processing parameters. The results revealed a better reproducibility and a higher yield of the direct preparation technique but the traditional sol-gel technique was found to be able to compensate accidental technological imperfections.



Key Engineering Materials (Volumes 361-363)

Main Theme:

Edited by:

Guy Daculsi and Pierre Layrolle




S. V. Dorozhkin et al., "The Differences between the Direct and Sol-Gel Syntheses of Silicon-Contained Calcium Phosphates", Key Engineering Materials, Vols. 361-363, pp. 107-110, 2008

Online since:

November 2007




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