Low temperature sintering and microwave dielectric properties of Ca5Ni4(VO4)6 ceramics

Low-temperature sinterable Ca5Ni4(VO4)6 ceramics were prepared by the conventional solid-state reaction route and its microwave dielectric properties were investigated. The crystalline phase, microstructure, and sintering behavior were studied by XRD and SEM. At the sintering temperatures ranging from 825 °C to 900 °C, pure phase Ca5Ni4(VO4)6 was obtained. The variation trend of εr was in accordance with that of relative density. The Q×f value was closely related to the packing fraction and relative density. The Ca5Ni4(VO4)6 ceramics sintered at 875 °C for 5 h possessed good microwave dielectric properties: εr=9.5, Q×f=54, 100 GHz (at 10.5 GHz) and τf=−60 ppm/°C, which also exhibited good chemical compatibility with silver electrode.