Crystallization and properties behavior of CaO-B ₂O ₃-SiO ₂ glass-ceramics

Glass-ceramics were prepared by sintering method. The effect of glass composition on sintering and crystallization behavior as well as properties of the glasses were investigated by using thermo gravimetry differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and property measurements. The results show that the optimal sintering temperature for this glass-ceramic is 875°C for 15min, and the major phases of this material are β-CaSiO ₃, CaB ₂O ₄ and SiO ₂. The glass-ceramic possesses excellent dielectric properties: ε _r=5.3, tanδ=0.003 at 10kHz and density about 2.48g/cm ³. The crystallization process occurred prior to densification the process, which is not favorable for densification. The CBS glass-ceramics of sintering is crystallization sintering and viscous flow sintering. Crystallization during the sintering and the densification are competing processes.