Crystallization of oxyapatite in glass-ceramics

The aim of the presented study was to investigate the crystallization of oxyapatites in glass-ceramics. The crystallization was analysed for three different glasses from the SiO2-B2O3-Al2O3-Y2O3-CaO-Na2O-K2O-F system with different F and B2O3 content after heat treatment. To characterize the microstructure and the phase formation, we used scanning electron microscopy (SEM) and room temperature X-ray diffraction (RT-XRD). The main results of this study showed that the oxyapatite crystallization is different in comparison to that of fluorapatite. We detected that the oxyapatite crystallizes according to the surface crystallization mechanism. Also we determined leucite as a secondary crystal phase in dependence of the B2O3 and F content. The results showed that a two-fold controlled surface crystallization of oxyapatite and leucite took place. (c) 2006 Elsevier Ltd. All rights reserved.