Influence of Al2O3 and B2O3 on Sintering and Crystallization of Lithium Silicate Glass System

Abstract

This article reports on the effect of Al2O3 and B2O3 added as dopants on the preparation of glass-ceramics (GCs) belonging to the lithium silicate glass system. The GCs are prepared by sintering route using glass powders. The reasons for the crystallization of the metastable crystalline phase lithium metasilicate (LS) are discussed and the impact of the dopants on the thermodynamics and kinetics of crystallization is investigated. The addition of dopants modifies the thermodynamic equilibrium of the system and this change is mainly entropy driven and also slowdown the kinetics of crystallization. Differential thermal analysis and hot-stage microscopy are employed to investigate the glass-forming ability, sintering, and crystallization behavior of the studied glasses. The crystalline phase assemblage studied under nonisothermal heating conditions in the temperature range of 800 degrees C-900 degrees C in air. Well sintered and dense glass-ceramics are obtained after sintering of glass powders at 850 degrees C-900 degrees C for 1 h featuring crystalline phase assemblage dominated by lithium disilicate (LS2).