Effects of CaF 2 addition on sintering behavior and microwave dielectric properties of ZnTa 2O 6 ceramics

Abstract

Microwave dielectric ceramics ZnTa 2O 6 were prepared by conventional mixed oxide route. The effects of CaF 2 addition on the microstructures and microwave dielectric properties of ZnTa 2O 6 ceramics were investigated. Formation of second phase can be detected at the high addition of CaF 2 (0.5–1.0 wt.%). Variation of grain shapes were observed with CaF 2 content increasing. The sintering temperature of CaF 2-doped ZnTa 2O 6 ceramics can be effectively lowered from 1400 °C to 1225 °C due to liquid phase effect. The microwave dielectric properties were affected by the amount of CaF 2 addition. At 1225 °C for 4 h, ZnTa 2O 6 ceramics with 0.25 wt.% CaF 2 possesses excellent microwave dielectric properties: ε r = 31.32, Q × ƒ = 73600 GHz(6.8 GHz) and τ ƒ = − 6.97 ppm/°C.