Low-temperature sintering and microwave dielectric properties of (1-x)MgTiO3-xCaTiO3 ceramics using bismuth addition

The effects of bismuth addition on the microwave dielectric proper-ties of (1-x)MgTiO3-xCaTiO(3) ceramics were investigated. MgTiO3-CaTiO3 (hereafter referred to as MCT) ceramics was prepared by the conventional solid-state method, With a small amount of Bi2O3 addition, the sintering temperature of MCT ceramics can be effectively lowered without degrading the dielectric properties at microwave frequency. At a constant Mg/Ca ratio, the Q x f values are strongly dependent on the amount of Bi2O3 addition and decrease with increasing bismuth content owing to the decrease of density, while the epsilon(r) value only shows a small increase. In the (1-x)MgTiO3-xCaTiO(3) system, the microwave dielectric properties could be controlled by varying x. At 1250degreesC. 0.94MgTiO(3)-0.06CaTiO(3) ceramics with 0.2mol% Bi2O3 addition gives a dielectric constant epsilon(r) of 22.6, a Q x f value of 53000 (7 GHz) and a tau(f) value of -2.9 ppm/degreesC.