Liquid phase sintering of MgTiO3–CaTiO3 microwave dielectric ceramics

The effects of CuO additive on the microstructures, the phase formation and the microwave dielectric properties of MgTiO3–CaTiO3 ceramics were investigated. The sintering temperature of CuO-doped 0.95MgTiO3–0.05CaTiO3 (95MCT) ceramics can be lowered to 1275 °C due to the liquid phase effect. The microwave dielectric properties are found strongly correlate with the sintering temperature as well as the amount of CuO addition. At 1275 °C, 0.95MgTiO3–0.05CaTiO3 ceramics with 0.25 wt.% CuO addition possesses a dielectric constant εr of 20, a Q×f value of 51 000 (at 7 GHz) and a τf value of −8.3 ppm °C−1. By appropriately adjusting the x value in the (1−x)MgTiO3–xCaTiO3 ceramic system, zero τf value can be obtained.