SYNTHESIS OF MAGNESIUM AND CARBONATE CO-SUBSTITUTED FLUOROAPATITES BY HYDROTHERMAL METHOD

Carbonate substituted fluorapatites (Ca10-x/2(PO4)(6-x)(CO3)(x)F-2 and magnesium carbonate co-substituted fluorapatites (Ca10-xMgx/2(PO4)(6-x)(CO3)(x)F-2 have been prepared using the hydrothermal method. The obtained results showed that both CO32- and Mg2+ were incorporated into the apatite structure for x <= 2 for both series. Carbonate ions were located on the phosphate site (type -B substitution). The introduction of CO32- and Mg2+ in the apatite framework involved a decrease of the crystallinity of the as prepared powders due to the reduction of the particle size. The as-prepared powders heat treated at 1000 degrees C in air revealed a partial decomposition of the carbonate apatite phase with a release of CO2 and a formation of CaO.