MgO–Al2O3–SiO2(MAS) glass–ceramics with controllable crystalline phases were successfully prepared using the melting method followed by heat treatment. The effects of the main components of glass on the crystallisation kinetics, nucleation, crystallisation and properties of glass–ceramics were investigated in detail. As the Al2O3and MgO contents increase and SiO2content decreases, the crystallisation peak temperature and activation energy of MAS glass decrease, while the crystal growth tends to follow a homogeneous nucleation crystallisation. The MAS glass nucleation temperature and time increase with higher concentrations of Al2O3and MgO and with a lower SiO2concentration. Mg2(Al4Si5O18) indialite and MgAl2O4spinel precipitate simultaneously in the MAS glass after crystallisation; the relative proportion of crystalline phases is related to the composition and crystallisation temperature. A higher SiO2content allows the formation of a dominant indialite phase, while higher MgO and Al2O3contents promote the formation of a dominant spinel phase. The MAS glass ceramic with a greater indialite phase has good dielectric properties with a dielectric constant of 6.499 and dielectric loss of 0.0064, while that of a higher spinel phase possesses improved mechanical properties, with a Vickers hardness of 715 Hv and a bending strength of 244.9 MPa.
MgO–Al 2 O 3 –SiO 2 glass-ceramics have been widely used in military, industrial, and construction applications. The nucleating agent is one of the most important factors in the production of glass-ceramics as it can control the crystallization temperature or the grain size. In this study, we investigated the effect of replacing P 2 O 5 with different amounts of TiO 2 on the crystallization, structure, and mechanical properties of an MgO–Al 2 O 3 –SiO 2 system. The crystallization and microstructure were investigated by differential scanning calorimetry , Raman spectroscopy , X-ray diffraction, scanning electron microscopy, and transmission electron microscopy . The mechanical properties were investigated by measuring the Vickers hardness , Young's modulus , and fracture toughness. The results showed that adding TiO 2 favored the precipitation of fine grains and significantly increased the Vickers hardness, Young's modulus, and fracture toughness of the glasses. Introducing an appropriate amount of TiO 2 can make a glass structure more compact, promote crystallization, and improve the mechanical properties of MgO–Al 2 O 3 –SiO 2 glass-ceramics.
危险品化学品经营许可证（带存储）