Microstructures and dielectric properties of CaTiO3–LaSrAlO4 composite ceramics

The microstructures and dielectric properties of xCaTiO3/(1−x)LaSrAlO4 composite ceramics were investigated. CaTiO3 and LaSrAlO4 could co-exist when the content of CaTiO3 was no more than 30 mol%, while LaAlO3 and CaO phases were observed in the composite ceramics with higher CaTiO3 content. The dielectric constant of the composite ceramics increased with increasing the additive content, and the dielectric loss generally increased with increasing the additive content because of the presence of phase boundary and the high dielectric loss of the minor phases. The temperature coefficient of dielectric constant decreased with increasing the additive content firstly, and then it increased abnormally when x equals to 40 mol%, finally it decreased with increasing the additive content further. The dielectric properties predicted from serial formula were most close to those obtained from experiment among the classical dielectric mixture rules.