Crystallization and mechanical properties of spodumene-diopside glass-ceramics

The crystallization of Li2O-Al2O3-SiO2 (LAS) glasses doped with different amounts of CaO and MgO were investigated. With CaO and MgO addition, the phases of beta-eucryptite, beta-spodumene and diopside were identified. Glass transition temperature (T-g) and. crystallization temperature (T-p) decreased, the frequency factor ( v) increased, this means the glass has the high propensity towards crystallization, while the activation energy (E) increased which implies barrier of crystallization increase. The effective overall reaction rate (k) decreased which means the effect of E on crystallization is more predominant than that of v. The Avrami parameter (n) decreased and microstructure of the materials transformed from equiaxed grain to fibrous grain. It can be concluded that CaO and MgO addition impede the crystallization of LAS glass, the crystallization mechanism-change from the bulk crystallization to surface crystallization. The mechanical properties of spodumene-diopside glass-ceramics were measured, and the flexural strength of glass-ceramics increases from 135 MPa to 186 MPa.