Low temperature sintering of low-loss ZnTiO3 microwave dielectric ceramics with Zn–B–Si glass

Abstract

The effects of Mg substitution, Zn–B–Si(ZBS) glass and extra TiO2 on the sintering behaviors, phase structures, microstructures and the microwave dielectric properties of ZnTiO3 ceramics were studied. The results show that a single ZnTiO3 phase was observed. Small amounts of Mg(x < 0.15) effectively increased the Q × f values of the (Zn1−xMgx)TiO3 (ZMT) ceramics, however, excessive Mg leads to a higher sintering temperature. Small amounts of ZBS(<3 wt.%) glass significantly lowered the sintering temperatures of ZMT ceramics and obtained excellent microwave dielectric properties. However, more than 3 wt.% ZBS glass leads to a secondary phase and causes abnormal grain growth, leading to inferior dielectric properties. (Zn0.9Mg0.1)TiO3 + 0.5 wt.% ZBS ceramic sintered at 900 °C shows the best dielectric properties: εr = 20.53, Q × f = 61630 GHz (at 7.44 GHz), τf = −76 ppm/°C. Extra TiO2 additions would modify the τf from negative to near zero. (Zn0.9Mg0.1)TiO3 + 3 wt.% ZBS + 10 wt.% TiO2 can be well sintered at 900 °C and obtained the dielectric properties: εr = 24.83, Q × f = 44342 GHz (at 6.65 GHz), τf = 3.4 ppm/°C.