Microwave Dielectric Properties and Microstructures of CuO-Modified (1-x)(Mg0.95Co0.05)TiO3–xCaTiO3 Ceramic System

The effects of CuO additives on the microstructures and the microwave dielectric properties of (1- x )(Mg 0.95 Co 0.05 )TiO 3 – x CaTiO 3 ceramics were investigated. The CuO additives can effectively reduce the sintering temperature of the ceramics to as low as 1175°C. With x = 0.08, at 1275°C, the 0.92(Mg 0.95 Co 0.05 )TiO 3 –0.08CaTiO 3 ceramic possesses excellent microwave dielectric properties: a dielectric constant ε r of 22.1, a Q × f value of 86400 GHz (at 7 GHz) and a τ f value of 5.4 ppm/°C. Sintered ceramic samples were characterized by using X-ray diffraction pattern and SEM. Dielectric constants ( ε r ) are not significantly affected by various additives and range from 20 to 23. By properly adjusting the x of (1- x )(Mg 0.95 Co 0.05 )TiO 3 – x CaTiO 3 ceramics, small temperature coefficients (< ±3 ppm/°C) of resonant frequency (τ f ) are obtained for 0.93(Mg 0.95 Co 0.05 )TiO 3 –0.07CaTiO 3 with 0.25 wt% CuO additives.