Stable Wollastonite-Cuspidine Glass-Ceramic Using Inexpensive Raw Materials

Transparent glasses within the K2O-CaO-SiO2-F composition were prepared. The influence of CaF2, TiO2, Li2O, Li2O-TiO2 and CeO2 additions on the crystallization of the parent glass has been investigated. Crystallization process gave wollastonite and cuspidine as the major phases whereas; xontolite and traces of miserite were developed as subordinate ones. Wollastonite was developed alone in the temperature range of 800 °C-1100 °C in Li2O-containing the base glass. Wollastonite and cuspidine were stable in the 800-1100 °C range in Li2O+TiO2-containing samples and within the 900 °C-1100 °C range in CaF2 and CeO2 containing samples. The microstructure of the Li2O-containing glass-ceramic showed an interlocked needle in nano-scale wollastonite crystals, while fibrous textures were developed in all other crystallized samples at 1000 °C. The thermal expansion coefficient value of the crystallized samples was between 7.596 to 8.708 X10 −6 °C−1 (20-500 °C) and the higher values reflect the increase of crystallization content of cuspidine and even the traces of miserite. This glass-ceramic is thought to be important in dental laboratories.