Rapid and quantitative determination of crystallization tendency of zinc tellurite glass melt by using temperature-gradient furnace

摘要

Quantitative thermal stability test of glass materials against crystallization is accelerated through a vertical temperature-gradient furnace. In the furnace, zinc tellurite glass melt is sucked into a 75cm-long glass capillary tube (ID 1.5 × OD 8 mmΦ) and the tube is kept inside to be annealed under a temperature gradient of 300～8OO°C/5Ocm. The time to precipitate is determined to make a set of T-T-T (Time-Temperature-Transform) diagrams for different composition and thermal hysteresis. Crystallization is not observed for 65TeO{sub}2-35ZnO and 7OTeO{sub}2-3OZnO (mol%) super-cooled glass melt after 4000s annealing but their stability decreased if the melts were once quenched to below their glass transition temperature before the annealing.