The Crystallization Behavior Determined by DTA Method of Glass-Forming Melts in the CaO-Ga₂O₃-GeO₂ System

Abstract

The temperatures of glass transition (T_g), crystallization (Tc) and melting (T_m) during heating were measured for compositions of 50-70CaO⋅15-40Ga₂O₃⋅0-20GeO₂. The crystallization temperature (T_k) during cooling and the fraction of precipitated crystals were measured from DTA data. Time-temperature-transformation (T-T-T) curves were determined experimentally. The position of the nose was 30s and 1050°C for the composition of 65CaO⋅25Ga₂O₃⋅10GeO₂. Cooling rate (Q)-temperature-transformation (X) (Q-T-T) curve is obtainable by plotting -Qⁿ⋅ln (1-X) vs. temperature, where n depends on crystallization mechanism and other factors and is 4 and 1 or 2 above and below 1150°C, respectively.