Microstructure, sinterability and properties of CaO-B2O3-SiO2 glass/Al2O3 composites for LTCC application

CaO-B2O3-SiO2 glass/Al2O3 composites were developed for low temperature co-fired ceramic (LTCC) applications and the sintering behaviors, phase compositions, microstructures and properties were investigated. The low melting point glass not only efficiently promoted the sintering densification of the composites, but also significantly improved the dielectric, mechanical and thermal performances. The glass/ceramic composite with 50 wt% glass sintered at 875 °C for 15 min exhibited bulk density of 3.12 g/cm3, εr of 8.06 and tanδ of 1.2×10−3 at 7 GHz, flexural strength of 204 MPa, thermal expansion coefficient of 5.47 ppm/°C, and thermal conductivity of 3.1 W/mK. It was compatible with Ag electrodes, which made it a promising candidate for LTCC application.