Properties, crystallization mechanism and microstructure of lithium disilicate glass-ceramic

In this study, lithium disilicate glass-ceramic in the TiO2-ZrO2-Li2O-CaO-Al2O3-SiO2 system was investigated for dentistry applications by incorporation of P2O5 and Nb2O5 as nucleation agent. The influence of the particles size (nano and submicron size) and nucleating agents on the crystalline phases, microstructure, crystallization mechanism and mechanical properties were investigated. Our data indicated that in ceramic glass with nano and submicron P2O5, the main crystalline phase was lithium disilicate. The results also showed that change of P2O5 particle's size had significant effect on the crystalline phases and microstructure. By replacement of submicron P2O5 with submicron Nb2O5, crystallization mechanism was changed from volume to surface crystallization. Due to the nature of crystalline phases as well as the directional crystallization and coarsening, many cracks were observed in the samples containing submicron Nb2O5. The composition of base glass was changed and nano Nb2O5 was added. As a result of these changes, the crystallization mechanism was altered. (C) 2009 Elsevier B.V. All rights reserved.