Influence of the dehydration procedure on the physicochemical properties of nanocrystalline hydroxylapatite xerogel

The influence of various dehydration procedures on the physicochemical properties of hydroxylapatite gel was examined. The best dehydration procedure is freezing, leading to the formation of a nanocrystalline hydroxylapatite powder without intermediate formation of a monolithic xerogel. Examination by the layer self-arrangement method, scanning electron microscopy, and atomic-force microscopy showed that the powder particles are spherical aggregates from 0.4 to 2.0 μm in size, consisting of nanoparticles 16–30 nm in diameter.