Abstract
Morphology-controlled hydroxyapatites (HAp) were prepared by phosphoration of various carcium carbonate used as seeds. Formation and coagulation processes of HAp were investigated by measuring the electrical conductivity and pH in the slurries and by means of X-ray diffraction, electron microscopic observation and measurements of IR spectra. When aqueous slurry of CaHPO4 (DCPD) was titrated into aqueous slurry of aragonite, platy particles were deposited on the aragonite surface and then the rod-like crystal of aragonite were covered with precipitated particles. Platy particles were composed of low crystalline HAp. Aragonite in the center of aggregate was dissolved away in aqueous solution of CH3000H- (CH3000) 2Ca. HAp aggregates with hollow were prepared. Ellipsoidal HAp aggregates with hollow were formed by phosphoration of vaterite used as seeds.
When phosphoric acid was titrated into aqueous slurry of calcite, on the other hand, spherical porous HAp aggregates were formed. Formation model of HAp aggregates with various morphology was proposed.
