Sintering behavior and microwave dielectric properties of (1−x)CaTiO3−xLaAlO3 ceramics

The sintering behavior, microstructure and microwave dielectric properties of (1−x)CaTiO3−xLaAlO3 (x=0.1, 0.3, 0.5, 0.7, 0.9, respectively) ceramics were investigated systematically by thermogravimetry-differential thermal analysis (TG-DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and a network analyzer. The result showed that forming temperature of the perovskite type crystal increased with increasing of x value. 0.9CaTiO3-0.1LaAlO3 ceramics were sintered well from 1 400 to 1 550 °C, its bulk density increased with sintering temperature, and microwave dielectric properties of the ceramics at 1 400 °C was shown as follows: relative dielectric constant ɛr=45.1, Q×f= 46 087 GHz and τf=−14.1×10−6/°C, respectively. But 0.7CaTiO3-0.3LaAlO3 ceramics were sintered well only when sintering temperature rose to 1 500 °C. (1−x)CaTiO3−xLaAlO3 (x=0.5, 0.7 and 0.9, respectively) were not sintered well up to 1 550 °C and the sintered samples exhibited porous characteristic and with low bulk density.