Microstructure, sintering and properties of CaO–Al2O3–B2O3–SiO2 glass/Al2O3 composites with different CaO contents

CaO–Al2O3–B2O3–SiO2 glass/Al2O3 composites for low temperature co-fired ceramics (LTCC) were prepared by tape casting method, and the effects of CaO content on the microstructure, sintering, and properties were discussed. Results showed that an appropriate CaO addition in CABS glass not only efficiently contributed to a dense glass/ceramic body, but also was endowed with better sintering characteristics, more excellent mechanical and dielectric properties. CABS glass/Al2O3 composites with 9 wt% CaO content sintered at 850 °C for 15 min exhibited bulk density of 3.10 g/cm3, Z-axis shrinkage of 15.3 %, flexural strength of 185 MPa, dielectric constant of 7.99 (at 7 GHz), dielectric loss of 1.8 × 10−3. After being co-fired with Ag electrodes, the glass/ceramic composites could perfectly match with Ag electrodes. It is indicated that this material could be a promising candidate for LTCC application.