Previous work by Miller et al (2000-04) has demonstrated that canasite-based glass ceramics have potential for use as biocompatible glass ceramics in hard-tissue augmentation. Several compositional modifications with respect to the stoichiometric formula were studied and biocompatability in stimulated body fluid was reported. However, the mechanism of crystallisation ere not investigated in detail. The purpose of this study was to examine the early states of nucleation and growth in our glass compositions using X ray diffraction and transmission electron microscopy. In stoichiometric compositions, laths of predominantly frankamenite homogeneously nucleate through the glass at around 700 deg C without the presence of a nucleating phase. However, in Na2O-deficient compositions, CaF2 particles act as nucleating sites for canasite laths.
