Effects of Sintering Temperatures on Microwave Properties of Mg4Nb2O9 Ceramics by the Solid-State Process

Microwave dielectric ceramics of Mg4Nb2O9 were prepared by the solid-state method and their microwave dielectric properties and microstructure were investigated in this study. The sintering ability and microwave dielectric properties of Mg4Nb2O9 ceramics were studied under various sintering temperatures ranging from 1200°C to 1350°C. As the sintering temperature increased from 1200°C to 1350°C, the density values, the er values and the Q·ƒ values increased and saturated at 1350°C.The ƒ values were ranged from -48.7 to -57.8 ppm/°C. Due to the increased density and appropriate grain growth the Mg4Nb2O9 ceramics sintered at 1350°C had the excellent microwave dielectric properties of er=12.3, Q·ƒ =108,000GHz and ƒ=-55.3ppm/°C.