HYDROTHERMAL SYNTHESIS AND CRYSTALLOGRAPHIC STUDY OF Ca-Sr HYDROXYAPATITE SOLID SOLUTIONS

Abstract

A continuous series of solid solutions in the system of strontium and calcium hydroxyapatite, Ca_10-xSr_xHAP (x= 0-10), was successfully synthesized by both high-temperature mixing method (HTMM) and low-temperature mixing method (LTMM) at 200°C for 12 hours under hydrothermal conditions. The samples were characterized by chemical analysis, electron microscopic observation and X-ray powder-pattern fitting. The site of the metal ions in the solid solutions was analyzed by the Rietveld method. The lattice constants of the solid solutions prepared by both of the methods varied linearly with Sr contents. It was found that Sr²⁺ ions in the solid solutions prepared by these two methods preferentially occupied the Ca (II) site in the apatite structure.