Noble metal-and its oxide- particulates dispersed hydroxyapatite (HAp) composite powders were prepared by ultrasonic spray-pyrolysis method. The morphology of the resulting particles was spherical; these fine powders consisted of the primary particle with sizes of about 100 nm. The particle size of the powders increased with the amount of noble metal ions in the starting solution. The obtained powders were composed of stichiometric HAp without Ca2+ ions-deficiency. In case of Au and Ag additives, noble metal (Au, Ag) particulates dispersed HAp was formed. In case of Pt additive, however, oxide (PtO) particulates dispersed HAp was formed.
