Effect of hydrolysis on the phase evolution of water-based sol-gel hydroxyapatite and its application to bioactive coatings

Dean-Mo LIu*, T. Troczynski, D. Hakimi

*Corresponding author for this work

研究成果: Article同行評審

36 引文 斯高帕斯(Scopus)

摘要

In a previous report, we demonstrated a successful synthesis of crystalline hydroxyapatite (HA) through the use of a water-based sol-gel process. It was shown that the apatite can be obtained at temperatures generally below 400°C, providing a great advantage for practical bioactive coating purposes. The influence of hydrolysis of phosphorus sol solution on the phase evolution of the resulting HA is the focus of this investigation. Experimental results show that, in the absence of acid catalyst, a long-term hydrolysis, i.e. > 4 h, is required for better evolution of apatitic phase. Such a phase evolution is mainly attributed to an increased concentration of apatitic phase, rather than improved crystallinity in the calcined gels. With the aid of acid catalyst, we found that a well-crystalline HA can be synthesized over a time period shorter by 2-3 orders of magnitude than those without catalyst, i.e. a few minutes. In almost all cases, a small amount of tricalcium phosphate (TCP) was detected, which may be explainable by the formation of oligomeric derivatives of the phosphorus sol during synthesis, where calcium phosphate derivatives with lower Ca/P ratio than stoichiometry can be developed. By selecting an optimal sol as a dipping source, highly-porous dental root specimens were coated and a thin, dense, adhesive (upon finger-nail scratching test) coating was achieved after calcinations at 375°C. An in vitro test also shows a bioactive character of the coating.

原文English
頁(從 - 到)657-665
頁數9
期刊Journal of Materials Science: Materials in Medicine
13
發行號7
DOIs
出版狀態Published - 17 七月 2002

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