SINTERING AND CRYSTALLIZATION OF A GLASS POWDER IN THE LI2O-ZRO2-SIO2SYSTEM

Sintering and crystallization of a 23.12 mol% Li2O, 11.10 mol% ZrO2, 6 5.78 mol% SiO2 glass powder was investigated, By means of thermal shri nkage measurements, sintering was found to start at about 650 degrees C and completed in a very short temperature interval (Delta T approxim ate to 100 degrees C) in less than 30 min, Crystallization took place just after completion of sintering and was almost complete at about 90 0 degrees C in 20 min. Secondary porosity prevailed over the primary p orosity during the crystallization stage. The glass powder compacts fi rst crystallized into lithium metasilicate (Li2SiO3), which transforme d into lithium disilicate (Li2Si2O5), zircon (ZrSiO4,), and tridymite (SiO2) after the crystallization process was essentially complete. The microstructure was characterized by fine crystals uniformly distribut ed and arbitrarily oriented throughout the residual glass phase.