Effect of K2O addition on crystallization and microstructure of Li2O-ZnO-Al2O3-SiO2 system glass-ceramics

The Li2O-ZnO-Al2O3-SiO2 system glasses With varying content of K2O were prepared. Crystallization processes of these glasses were investigated using X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Microstructure of the glass-ceramics was studied using scanning electron microscopy (SEM). The sequence of crystallization of Li2O-ZnO-Al2O3-SiO2 glasses can be divided into three stages such as crystallization of beta(1)-Li2ZnSiO4, crystallization of Li2Al2Si3O10 and conversion of beta(1)-Li2ZnSiO4 to gamma(0)-Li2ZnSiO4. The K2O content doesn't vary the crystallization sequence but enhances the crystallization of beta(1)-Li2ZnSiO4. At the same time the introducing of K2O in Li2O-ZnO-Al2O3-SiO2 system hinders the crystallization of Li2Al2Si3O10 and the transformation of beta(1)-Li2ZnSiO4 to the more stable phase gamma(0)-Li2ZnSiO4.