CHARACTERIZATION OF THE MAGNESIUM-SUBSTITUTED HYDROXYAPATITE PREPARED BY ULTRASONIC SPRAY-PYROLYSIS TECHNIQUE

抄録

Magnesium-substituted hydroxyapatite (Mg-HAp) powders with the formula of Ca_10-xMg_x(PO₄)₆(OH)₂, where x=0, 0.25, 0.5, 0.75, 1, 1.5, 2, 5 and 10, were prepared by spray-pyrolyzing the aqueous solutions in the Ca(NO₃)₂-Mg(NO₃)₂-(NH₄)₂HPO₄-HNO₃ system. Although only the hydroxyapatite (HAp) was present in the case of x=0, β-tricalcium phosphate (β-TCP) formed with increasing x value. Only β-TCP was present in the case of x=1.5; however, it was gradually changed into the amorphous phase with a further increase in x value. The data on lattice constants of the HAp and/or β-TCP in the range of x=0 to 1 showed that the Mg²⁺ ions could be substituted with the Ca²⁺ ions in HAp; the maximum substituted amount was estimated to be ~7.7 mol%.