Synthesis of calcium-strontium phosphate fluor-hydroxyapatites by neutralisation

In this work, the method of neutralisation was used for the first time for the preparation of calcium-strontium fluor-hydroxyapatites. Ca-Sr fluor-hyd roxyapatites were prepared by neutralisation of a solution containing phosp horic acid and ammonium fluoride by an aqueous suspension of calcium oxide and strontian at room temperature. Apatites with various amounts of stronti um and fluoride were prepared and characterized by X-ray diffraction. They had the general formula Ca10-xSrx(PO4)(6)(OH)(2-y)F-y (0 less than or equal tox less than or equal to 10, 0 less than or equal toy less than or equal to2). The cell parameters and the crystal size were determined from X-ray d iagrams. The apatites were better crystallized when the amount of strontium increased and no effect of fluorine ions on the crystal size was detected. After heating at 600 degreesC, the cell parameters increased with the amou nt of strontium; raising the amount of fluoride decreased the "a" value and increase the "c" value. These results show that it is possible to prepare calcium-strontium fluor-hydroxyapatites at room temperature by an easy and non-polluting method.