Low temperature sintering and microwave dielectric properties of ZnTiNb2O8 ceramics with BaCu(B2O5) additions

The phases, microstructure and microwave dielectric properties of ZnTiNb2O8 ceramics with BaCu(B2O5) additions prepared by solid-state reaction method have been investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The pure ZnTiNb2O8 ceramic shows a high sintering temperature of about 1250 °C. However, it was found that the addition of BaCu(B2O5) lowered the sintering temperature of ZnTiNb2O8 ceramics from above 1250 °C to 950 °C due to the BCB liquid-phase. The results showed that the microwave dielectric properties were strongly dependent on densification, crystalline phases and grain size. Addition of 3 wt% BCB in ZnTiNb2O8 ceramics sintered at 950 °C afforded excellent dielectric properties of ɛr = 32.56, Q × f = 20,100 GHz (f = 5.128 GHz) and τf = −64.87 ppm/°C. These represent very promising candidates for LTCC dielectric materials.