Crystallization and sintering characteristics of CaO–Al 2O 3–SiO 2 glasses in the presence of TiO 2, CaF 2 and ZrO 2

Abstract

In this study, the effects of different amounts of TiO 2, ZrO 2 and CaF 2 nucleating agents on sinterability, crystallization, mechanical properties and chemical resistance of glass–ceramics belonging to the CaO–Al 2O 3–SiO 2 system were investigated, using differential thermal analysis (DTA), X-ray diffractometry (XRD), scanning electron microscopy (SEM), mechanical and chemical resistance measurements. It was found that in CaF 2 containing samples, the sinterability, crystallization and mechanical properties were improved by increasing of CaF 2 amount. However, addition of ZrO 2 and TiO 2 increases the firing temperature required for complete densification of specimens. Our experiments showed that fluctuations of chemical composition of the residual glass phases during sintering were responsible for these dissimilar trends and greatly influenced mechanical and chemical properties. According to the obtained results, appropriate sinterability, acceptable mechanical and chemical properties, as well as desirable whiteness of the most promising specimens make them suitable choices for floor tile applications. The main crystallization phases in all fully sintered glass–ceramics were wollastonite, anorthite and calcium aluminum silicate.