In view of the fact that TiO2 and Fe2O3 in slag or tailings can be used as nucleating agent, three kinds of nucleating agent of TiO2, TiO2+ZrO2 and TiO2+Fe2O3 were designed to prepare CaO-MgO-Al2O3-SiO2 (CMAS) system glass ceramics by melting method and two-steps crystallization heat-treatment. The crystalline phase, microstructure, mechanical properties and dielectric properties of CMAS system glass-ceramics were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), microhardness tester and broadband dielectric impedance spectrometer, respectively. The results show that diopside and magnesium titanate occur when TiO2 is added solely; the merwinite is precipitated when TiO2 and ZrO2 are added together, and zirconium titanate is precipitated additionally when the amount of TiO2 is increased; Fe3O4 and rhoenite occur when TiO2 and Fe2O3 are added together. Although the phase composition changes with the type of nucleating agent, the grain size is within 200 nm with uniform distribution, giving rise to the mechanical properties of glass-ceramics. The Vickers hardness (HV5) of all samples is about 8 GPa, while the fracture toughness is around 1.25 MPa•m1/2. When the addition of TiO2 and Fe2O3 increases, the Vickers hardness of the sample can reach 8.15 GPa, which is conducive to the abundant addition of solid waste containing titanium or iron. The dielectric constant of the sample is about 11 with the dielectric loss about 10-3 order of magnitude under the appropriate content of nucleating agent. It is indicated that this kind of glass-ceramics also has application prospect in the field of electronic packaging or mobile communication. © 2021, Materials Review Magazine. All right reserved.
