Calcium phosphate (CaP) materials are chemically similar to human bone and tooth enamel. As a result, they have been used in numerous biomedical and dental applications. The aim of the current work was to synthesise two CaP powders, namely hydroxyapatite (HAp) and dicalcium phosphate dihydrate (DCPD) via a wet chemical precipitation method. During synthesis, pH was either kept constant using a pH-stat autotitrator or allowed to drift, age times were varied and in some experiments seed material was added to induce crystal growth. Phase identification was achieved using Fourier-transform infared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis. Crystal morphology was evaluated using scanning electron microscopy (SEM). It was found that CaP phase precipitation is highly dependent on pH and not on initial Ca/P molar ratio. Ageing time of solutions in non-seeded experiments had a significant effect on crystallinity and phase precipitation from solution. Seeding effected the rate of phase transformation, crystallinity and morphology of CaP powders. A novel ‘grapevine’ morphology was observed for precipitates obtained from metastable solutions which had been seeded with highly crystalline DCPD.
Journal of the Australian Ceramic Society – Springer Journals
Published: Sep 22, 2017