Effect of ZrO2 on crystallization of CaO–P2O5–SiO2 glasses

The influence of ZrO2 content on the crystallization mechanisms of CaO–P2O5–SiO2 biological glasses was investigated by DTA, XRD and SEM. Kinetic parameters such as the crystallization activation energy (E) and the crystal growth index (n) have also been evaluated according to the JMA equation. In the studied glass system, the larger the ZrO2 content, the lower the crystallization peak temperature, Tp. Nevertheless the high value of Tp did not mean a large E value. The most effective addition of ZrO2 in the CaO–P2O5–SiO2 glasses was about 5.7 wt.%. The difference of E between the base glass (no ZrO2 added) and the glass containing the most effective addition of ZrO2 was about 100 kJ/mol, suggesting that ZrO2 could promote the crystallization effectively.