Calcium apatite prepared from calcium hydroxide and orthophosphoric acid

Abstract

Calcium hydroxyapatite has been prepared due to a direct precipitation reaction between 0.3 m 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. © 1991 Chapman and Hall Ltd.