Effect of MgO on the Crystallization Behavior and Properties of Glass-Ceramics

As an important advanced decoration material, glass-ceramics has attracted much attention. By means of XRD, SEM and mechanical properties tests, this research studied the sintering and crystallization behavior during the preparation of CaO-MgO-Al2O3-SiO2 glass-ceramics. Results showed that with increase in MgO content, crystallization temperature increased, linear sintering shrinkage (%) decreased and porosity number increased, leading to a lower apparent density. However, with increase in temperature and time, linear shrinkage (%) increased. In addition, the increase of MgO made the vibration frequency of infrared spectrum move to the low-frequency, showing transformation from wollastonite to pyroxene phase. With increase in MgO content, particle size decreased, crystallization rate increased, microhardness of glass-ceramic material increased and flexural strength increased initially, then decreased. The flexural strength of glass-ceramics with 10% MgO can be 103 MPa.