NUCLEATION AND CRYSTALS GROWTH IN THE VOLUME OF GLASS Li2O–Al2O3–SiO2 SYSTEM

Abstract

By the Marotta et al method, temperature of 670 ?C at a holding time of 2 hours provides the maximum rate of nucleation the crystalline phase of ?-eucryptite-like solid solutions was found. The activation energy of nucleation and the Avrami parameter were measured by the DSC method, allowing to estimate the crystallization characteristics. The gradient crystallization method has established the temperature range of heat treatment, within which it is possible to obtain a transparent glass-ceramic. The refinement of regime the nucleation stage made it possible to reduce the time of the second stage crystallization required for the complete formation of the transparent glass-ceramic structure. Varying the holding time at a temperature of 710 ?C makes it possible to smoothly change the CTE in the range of ?(3…+41)?10–7 K?1 in the temperature range from ?120 to +500 ?C.