Preparation and thermal stability analysis of hydroxyapatite derived from the precipitation process and microwave irradiation method

Abstract

Thermally stable hydroxyapatite (HAP) polycrystals were prepared using H 3PO 4, glucose and Ca(NO 3) 2·4H 2O, as starting materials with microwave irradiation method and coprecipitation method, respectively. The crystal structure was monitored by XRD. The calcium/phosphorous molar ratio of the different as-precipitated hydroxyapatite was determined by ICP. The results show that various parameters such as aging time, microwave irradiation power and time have significant effects on thermal stability of hydroxyapatite. The thermal stability of HAP increases with protraction of aging time, microwave irradiation time and power, respectively. Aging time reached to 24 h; HAP made by precipitation can exist stably at calcination of 1200 °C. Microwave time and power was 1 h or 700 W, respectively; the sample quenched from 1200 °C is still HAP.