EFFECTS OF AL P COMPOSITION RATIO ON THE CRYSTALLIZATION OF MGO-CAO-AL2O3-SIO2-P2O5 BIOGLASS-CERAMIC SYSTEM/

Effects of the Al/P ratio on the crystallization of apatite and anorth ite were investigated by differential thermal analyses on a series of glasses with the nominal composition of 3.0 wt% MgO, 35.0 wt% CaO, 41. 4 wt% SiO2, and 20.6 wt% (Al2O3 + P2O5). It is shown that the activati on energy for crystallization of apatite decreases with decreasing Al/ P ratio, but that for crystallization of anorthite, on the contrary, i ncreases. The Avrami parameter, n, was also estimated to be 2 and 1 fo r apatite and for anorthite, respectively.