Microstructure, sinterability and properties of ZnO-B2O3-SiO2 glass/ Al2O3 composites for LTCC application
摘要
A new type of glass/ Al2O3 ceramic composite material was prepared by the conventional solid-state method for lead-free low-softening ZnO-B2O3-SiO2 (ZBS) glass. The effects of glass content and sintering temperature on the phase structure, sintering performance, microstructure, dielectric properties, thermal properties and mechanical properties of the composite materials were investigated by adding different mass fractions of ZnO-B2O3-SiO2 glass into Al2O3 ceramics. The results show that the doped ZnO-B2O3-SiO2 glass effectively reduced the sintering temperature of Al2O3 ceramics, and the sintering aid ZnO-B2O3-SiO2 glass had no crystalline phase. The ZBS/ Al2O3 composites sintered at 875–925 ℃ mainly contain two crystalline phases, ZnAl2O4 and Zn2SiO4, and the content of the phases depended on the composition of the composites and the sintering temperature. When the content of ZnO-B2O3-SiO2 glass was 74 wt.%, and the composites were sintered at 875 ℃ for 1 h, the volume density of the composites was 3.49 g/cm3, the thermal conductivity λ was 1.46W/mK, the thermal expansion coefficient CTE was 5.52/ppm ℃, the flexural strength was 155 MPa, the relative dielectric constant was 6.28, and the dielectric loss was 0.937 × 10−3 (@12.571 GHz). The dielectric properties are the best, and it has a good application prospect in LTCC at high frequencies.