Effect of ZnO on Crystallization of Zircon from Zirconium-Based Glaze

The promotion of zircon (ZrSiO4) crystallization by ZnO from a zirconium-based frit glaze was studied and the possible mechanism was discussed. X-ray diffraction was used to analyze the relative quantities of zircon and other transitional crystals in the samples. The results show that ZnO can significantly decrease the crystallization temperature of zirconium-based glaze, depress the formation of Ca2ZrSi4O12, and promote the devitrification of transitional crystals t-ZrO2 and Ca2ZnSi2O7, as well as lead to the formation of more zircon than the ZnO-free glaze. It was also found that zircon not only can form from the interaction between t-ZrO2 and SiO2 but also can devitrify directly from the glass phase of zirconium-based glaze.