Synthesis of nano-sized hydroxyapatite by ultrasound irradiation

Ultrasound irradiation is an effective means of synthesizing fine particles by promoting contact between ions in a solution. We previously reported the synthesis of nano-sized amorphous calcium carbonate particles (specific surface area: 70 m(2)/g) using this method. The present study focused on the production of nano-sized hydroxyapatite (HAp) particles with a high specific surface area using ultrasound irradiation. The initial Ca/P atomic ratio was adjusted from 1.00 to 2.00 and the effects on the resulting HAp particles was investigated. HAp particles were found to be easily formed within 5 min of the start of the reaction, and were confirmed to have a single phase using X-ray diffraction analysis. The maximum specific surface area of the particles was approximately 130 m(2)/g.