Sintering densification behaviors and crystallization characteristics of glass–ceramics formed by two types of CaO–B2O3–SiO2 glass

The sintering densification behaviors and crystallization characteristics of CBS glass have been investigated systematically, and a new CBS glass composite system containing two types of CBS glass is reported. The results demonstrated that the sintering densification characteristic of single CBS glass and CBS composite could be divided into two stages: the fast and slow densification stage. The temperature range of the fast densification stage of single CBS glass is quite narrow (680–710 °C), while CBS composite gets a wider one (680–730 °C). In result, more moderate sintering densification process, which benefits the co-firing compatibility with electrode materials, is obtained in CBS composite. The major crystalline phases of the CBS glass and CBS composite were CaSiO3 and CaB2O4. CBS glass sintered at 910 °C for 10 min exhibited excellent microwave dielectric properties of dielectric constant value of 6.4 and quality factor value of 11,110 GHz, while CBS composite showed dielectric properties of dielectric constant value of 6.1 and quality factor value of 10,640 GHz, which meets the requirements for LTCC applications.