Effect of Calcination Conditions on Phase Formation of Calcium Phosphates Ceramics Synthesized by Homogeneous Precipitation
Phase composition of calcium phosphate ceramics is a characteristic directly related to the biological response of implants due to the differences in mechanical and biochemical properties of these compounds. In this sense, it was evaluated in this work the crystalline phase evolution of calcium phosphates samples synthesized by wet precipitation route. Fixing Ca/P atomic ratio as 1.67, precipitation was carried out from heated aqueous solutions of calcium chloride and ammonium hydrogen phosphate, in ammonium medium (pH = 10). After washing and drying steps, calcination was performed at 600 to 1100 oC for 1 and 3 hours. Milled and pressed powders were sintered at 1250 oC for 1 hour. Samples were characterized by X-ray diffraction, chemical analysis, scanning electron microscopy, gaseous adsorption, laser diffraction and apparent density measurements. Results indicate the formation of a biphasic calcium phosphate ceramic containing hydroxyapatite as a major phase and β - tricalcium phosphate, the later obtained by heat treatment above 600 oC.
Lucio Salgado and Francisco Ambrozio Filho
D. R. R. Lazar et al., "Effect of Calcination Conditions on Phase Formation of Calcium Phosphates Ceramics Synthesized by Homogeneous Precipitation", Materials Science Forum, Vols. 530-531, pp. 612-617, 2006