Low Temperature Sintering of BaO–ZnO–TiO2 Ceramics for LTCC Applications

Abstract

In order to develop a new middle dielectric constant LTCC materials, the effects of BaO–ZnO–TiO2–B2O3–SiO2(BZTBS) and/or BaCu(B2O5)(BCB2) on the phase composition, microstructure and microwave dielectric properties of BaO–ZnO–TiO2 ceramics were investigated by solid-state reaction. It was found that BCB2 mainly worked as sintering aids to lower the sintering temperature and the key role of BZTBS was to affect the phase composition in favour of showing a high Q×f value. Therefore, when 5wt% BZTBS+6wt% BCB2 were co-doped, the sintering temperature was down to 850°C, and the microwave dielectric properties were improved significantly because the densification and grain size distribution were not only improved but also the phase composition was controlled. At last, this ceramics sintered at 850°C for 0.5 h showed good microwave dielectric properties: εr=28.4, Q×f=8,030 GHz and τf=2 ppm/°C. Also, it was compatible with Ag electrodes, so it was a promising candidate for LTCC application.