Effects of Crystallization Schedule on Microstructure and Properties of Mg0.6Al1.2Si1.8O6 Transparent Glass-ceramics

MgO-Al2 O3-SiO2( MAS) system glass-ceramics have the properties of high mechanical, low dielectric loss, excellent chemical stability and thermal stability, showing great application value In electron, military, architecture and other fields. MAS transparent glass-ceramics were prepared by controlling the precipitation of Mg0.6Al1.2 Si1.8O6 solid solution crystalline phase by melt quenching method. Effect of crystallization schedule on the microstructure and properties of glass-ceramics was investigated by XRD, SEM, hardness meter, bending strength tester and UV-Vis-NIR. The results show that when crystallization temperature increases from 950 X^ to 1 020 °C, the crystalline phase of glass-ceramics is Mg0.6Al1.2Si1.8 O6 solid solution, and the glass-ceramics are transparent. When crystallization temperature rises to 1 050 °C) and higher, the crystalline phase is cordierite and the glass-ceramics are opaque. Mg0.6Al1.2 Si1.8O6 phase transforms to cordierite phase when crystallization temperature increase. Compared with the cordierite, the refractive index of Mg0.6Al1.2 Si1.8O6 phase is closer to that of glass phase. The crystalline phase content of glass-ceramics increases from 42. 9wt% to 97.5wt% with the increase of crystallization time from 2 h to 10 h. The average grain size of glass-ceramics increases from 17.50 Mm to 30.58 ^m with the increase of crystallization time from 4 h to 10 h. The light transmittance of glass-ce- ramics slowly decreases with prolonging crystallization time. The thermal expansion coefficient slowly increases with prolonging crystallization time. The Vickers hardness Increases first and then flattens, and the bending strength increases first and then decreases with prolonging crystallization time. The suitable crystallization temperature is determined as 1 020 °C, and the suitable crystallization time is determined as 8 h. When heat-treated at optimum crystallization schedule, the glass-ceramics have the best comprehensive properties, which have light transmittance of 83% In visible light region, thermal expansion coefficient of 3.857x10-6/°C(600 °C), Vickers hardness of 10.2 GPa, and bending strength of 200 MPa. © 2024 Cailiao Daobaoshe/ Materials Review. All rights reserved.