Low-temperature sintering and microwave dielectric properties of (1−x)Mg4Nb2O9−xCaTiO3 ceramics

The effect of V2O5 additive on the sinterability, microstructure and microwave dielectric properties of (1−x)Mg4Nb2O9−xCaTiO3 (0≤x≤0.7) ceramics was investigated. Two-phase system was confirmed by the X-ray diffraction patterns and Raman spectra analysis. The specimens with 1.7 wt% V2O5 addition can be well-sintered at the temperature as low as 1150 °C. As the x value increased from 0.2 to 0.7, the τf of specimens can be promoted from −44 to 134 ppm/°C. In particular, a new 0.5Mg4Nb2O9-0.5CaTiO3 ceramics sintered at 1150 °C for 5 h exhibited excellent microwave dielectric properties of εr=20, Q×f=48 000 GHz and τf=−12 ppm/°C. It is proposed as a candidate material for today's 3G application.