Crystallization Behavior of SiO2–Al2O3–ZnO–CaO Glass System at 1123–1273 K

Abstract

The crystallization characteristics of a glass, used as the matrix of high‐temperature protective coatings, based on SiO2–Al2O3–ZnO–CaO with the addition of TiO2 and ZrO2 at a temperature range of 1123–1273 K have been investigated. At 1273 and 1173 K, tetragonal zirconia doped with Ti and Ca, initially precipitated from the melt. At 1123 K, however, zirconolite instead of zirconia precipitated as the primary phase. The secondary precipitates were zircon and titanite in the glass fired at 1273 K, titanite and willemite at 1173 K, and zirconolite, titanite, and willemite at 1123 K, respectively. It is proposed that the temperature‐dependent solubility of Ca and Ti in ZrO2 significantly affects the type and volume fraction of crystals precipitated from the glass.