HYDROXYAPATITE SYNTHESIZED FROM NANOSIZED CALCIUM CARBONATE VIA HYDROTHERMAL METHOD

Hydroxyapatite (HAp) was synthesized using a hydrothermal treatment method. Nanosized calcium carbonate (CaCO₃) was used as the calcium source, while (NH₄)₂HPO₄ was used as the phosphorous source. Well-crystallized HAp and a small amount of β-tricalcium phosphate (β-TCP) were obtained after the hydrothermal reaction. FT-IR spectra show that under conditions of pH 6 and 250°C, the functional groups of OH^- and PO₄^3- were stronger than those under pH 10. This exhibits that the powder synthesized at pH 6 has more HAp phase than that at pH 10. SEM and TEM images show that HAp exhibits a rod-like shape about 10μm long and about 0.7μm wide at pH 6 and 250°C. After hydrothermal reaction at pH 6 and 250°C, most products are rod-like HAp with a small amount of β-TCP synthesized as a byproduct and some residual CaCO₃.