Sintering and crystallization of a glass powder in the Li 2O-ZrO2-SiO2 system

Sintering and crystallization of a 23.12 mol% Li2O, 11.10 mol% ZrO2, 65.78 mol% SiO2 glass powder was investigated. By means of thermal shrinkage measurements, sintering was found to start at about 650\ub0C and completed in a very short temperature interval (\u394T 48 100\ub0C) in less than 30 min. Crystallization took place just after completion of sintering and was almost complete at about 900\ub0C in 20 min. Secondary porosity prevailed over the primary porosity during the crystallization stage. The glass powder compacts first crystallized into lithium metasilicate (Li2SiO3), which transformed into lithium disilicate (Li2Si2O5), zircon (ZrSiO4), and tridymite (SiO2) after the crystallization process was essentially complete. The microstructure was characterized by fine crystals uniformly distributed and arbitrarily oriented throughout the residual glass phase