HYDROTHERMAL PREPARATION OF HYDROXYAPATITE SOLID SOLUTIONS WITH VARIOUS METAL IONS

Abstract

The continuous solid solutions in the systems of Ca-Cd HAp, Ca-Sr HAp and Ca-Pb HAp were successfully synthesized at 200°C for 12 hours under hydrothermal conditions. The Rietveld analysis indicates that the Cd ions have a slight tendency to occupy the M (2) sites in the apatite structure, Sr ions preferentially occupy the M (2) sites with high Sr content, and Pb ions showed the high preferential occupancy in the M (2) sites. The preferential occupancy of metal ions can be explained mainly by ionic radius and electronegativity of the metal ions.