Effects of MgO, SrO and La2O3 Co-doping on Structure and Properties of (Zr0.8Sn0.2)TiO4 Ceramics

(Zr0.8Sn0.2)TiO4 (ZST) ceramics were fabricated via conventional solid-state reaction method which was promoted by liquid phase. The effects of MgO, SrO and La2O3 co-doping ZST ceramics on phase composition, microstructures, sintering behavior, and high frequency dielectric properties were investigated systematically. The results showed that the main crystalline phase of the ceramics was ZST. The appropriate amount of MgO, SrO and La2O3 additions effectively decreased the sintering temperature of ZST ceramics and improved the microwave dielectric properties. The increment of MgO addition influenced comprehensive properties of ZST ceramics slightly. The decrement in bulk densities, dielectric constants and Qxf values with excessive SrO addition was due to incomplete growth of grains, incompact structures and increasing porosities. Additionally, the additives did not affect obviously the temperature coefficient of resonant frequency (tau(f)) of the ceramics. When added 0.2wt% MgO, 0.6wt% SrO and 1.0wt% La2O3 and sintered at 1300 degrees C for 5 h, ZST ceramics displayed the optimum comprehensive properties: p = 5.14 g/cm(3), epsilon(T) = 40.11, Qxf = 51000 GHz (f = 5.61 GHz), tau(f) = -2.85x10(-6)degrees C-1.