Crystal Nucleation and Growth in Li2O–Al2O3–SiO2 Base Glass Bulk

Abstract

The crystallization properties of glass with a Li₂O–Al₂O₃–SiO₂ based multicomponent composition were studied. Using the Marotta, et al. method, it was found that at 670°C with 2-h soaking affords the maximum rate of nucleation of the crystalline phase of β-eucryptite-like solid solutions. The activation energy of nucleation and the Avrami parameter were measured by means of DSC. Using the gradient crystallization method, the temperature ranges of heat treatments where transparent sitalls obtain were determined. More accurate determination of the temperature-time parameters of the nucleation stage made it possible to shorten the time of the second stage of sitallization that is necessary for the complete formation of the structure of transparent sitalls. By varying the soaking time at 710°C it was possible to vary the LTEC evenly in the temperature interval –120... +500°C in the range (–3... +41) × 10 ^–7 K^–1.