Synthesis and characterization of La2O3/BaO-doped (Zr0.8Sn0.2)TiO4 microwave ceramics

(Zr0.8Sn0.2)TiO4 microwave ceramics using La2O3 and BaO as sintering aids were prepared by the conventional mixed oxide route and investigated by XRD, SEM, EDS and dielectric measurements. The sintering temperature could be effectively lowered by using La2O3 and BaO additives. La2O3/BaO-doped ZST ceramics sintered at 1350 °C/4 h showed very good dielectric properties: εr=41, τf=−3.79 ppm/°C, and Q=9800 at 1.8 GHz. In La2O3/BaO-doped ZST ceramics, a major ZST solid solution is formed with three minor phases: (i) (Ti0.8Zr0.1Sn0.1)O2ss, a TiO2-based solid solution, (ii) orthorhombic La2/3TiO3 containing 3.4 at.% Ba, (iii) orthorhombic Ba2TiO4 containing 2.2 at.% Zr and 2.8 at.% Sn.