Hydrothermal Synthesis of Ultrafine Hydroxyapatite Single Crystals

Abstract

Hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂; HAp) ultrafine powders sy nthesized by a wet method were treated under hydrothermal conditions. The HAp particles obtained at 200°C under 2MPa for 10 h were hexagonal prism-shaped fine single crystals, about 25 nm×90 nm in size, the median aspect ratio obtained from the transmission electron micrograph. was 3.2.
The quantitative chemical analysis, infrared (IR) spectra and X-ray diffraction (XRD), showed the presence of small amounts of CO₃^2- in the OH^- site. The HAp could be given by the formula: Ca₁₀(PO₄)₆(OH)_1.81±0.03(CO₃)_0.095±0.015.