Low temperature sintering and microwave dielectric properties of Bi4B2O9-added 0.25CaTiO3–0.75(Li1/2Nd1/2)TiO3 ceramics

The effects of Bi4B2O9 addition on the sintering behaviour, microstructure and microwave dielectric properties of 0.25CaTiO3–0.75(Li1/2Nd1/2)TiO3 ceramics have been investigated. The addition of Bi4B2O9 effectively reduced the sintering temperature to 1200 °C. The secondary phase was observed for the 7.5 wt% Bi4B2O9-doped sample sintered at 1300 °C. The dense microstructure was developed and the grain size was increased with the creasing of Bi4B2O9 content. Bi4B2O9 addition significantly affected the microwave dielectric properties. The Q×f0Q×f0 value was increased by the Bi4B2O9 addition due to increased grain size and the temperature coefficient of resonant frequency (τfτf) can be tailored by the Bi4B2O9 addition as well. In particular, the excellent microwave dielectric properties of εr=114εr=114, Q×f0Q×f0 = 2830 GHz and τfτf = −7.8 ppm/°C could be obtained for the 10 wt% Bi4B2O9-doped sample sintered at 1200 °C.

► Bi4B2O9 was used for reducing the sintering temperature of 0.25CT-0.75LNT ceramics.
► Bi4B2O9 can be used to tailor the tauftauf of 0.25CT-0.75LNT to near-zero.
► The Q×f0Q×f0 of 0.25CT-0.75LNT was enhanced by the Bi4B2O9 addition.
► The effect of Bi4B2O9 addition on the grain size is also introduced.