Effects of CaO and La2O3 doping of (Zr0.8Sn0.2)TiO4 ceramics on the densifying behavior and microwave dielectric properties

The effects of CaO-La2O3 additives on sintering temperature and microwave dielectric properties of (Zr0.8Sn0.2) TiO4 (ZST) ceramics prepared by solid-state reaction method were investigated. Structural characterization and microstructure of materials were studied via X-ray diffraction and scanning electron microscopy. crystalline and single phase exhibiting orthorhombic symmetry were identified. Small quantities of CaO and La2O3 promoted the densification of the ceramics improving dielectric properties, otherwise, an excessive CaO and La2O3 amount gave an abnormal grain growth which deteriorated dielectrical parameters. Dense ZST ceramics doped with 0.5% CaO and 1 wt% La2O3 were attained after sintering at 1335 degrees C during 4h, in air atmosphere. Microwave dielectric parameters of epsilon(r) = 39.56, Q x f = 44100 GHz (at 5.6 GHz), tau(f) = -1.66 ppm/degrees C were derived.