Calcium apatite prepared from calcium hydroxide and orthophosphoric acid
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Calcium hydroxyapatite has been prepared due to a direct precipitation reaction between 0.3m orthophosphoric acid solution and 0.1 mol calcium hydroxide dispersed in 200 ml water. The effect of the addition rate of the acid solution, reaction temperature and mixing molar Ca/P ratio is examined on the thermal stability and stoichiometry of the precipitates. Optimum conditions for HAp suitable for dense ceramics are derived from the results. The non-stoichiometry is interpreted in terms of the pH profile in the vicinity of the hydroxide particles and the state of the orthophosphate ions.
KeywordsPrecipitation Thermal Stability Acid Solution Reaction Temperature Apatite
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