Microstructure and dielectric properties at lowfrequency of BaWO₄/(B a|Sr)TiO₃ ceramic composites

The new ceramic composites of BaWO₄/(B a，Sr)TiO₃ were successfully fabricated by a standard ceramic
processing. The sintering properties，microstructure and the dielectric properties of BaWO₄/(Ba，Sr )TiO₃ were systemically studied by means of XRD，SEM and property measurement. The results show that BaWO₄/(Ba，Sr)TiO₃ could be well sintered at 1250～1350℃ without chemical reaction between perovskite and scheelite phases. With the BaWO₄ mass fraction increasing，the density of the ceramic composites increases apparently，the dielectric permit tivity and tunability decrease gradually，and the dielectric loss has a slight change at the grade of 10^-3. Typically，for the sample with 60% BaWO₄ and 40% Ba 0.5Sr 0.5TiO₃(mass fraction)，the tunability under external  DC field of 2 V·μm^-1 is 14.7%，and the dielectric constant and dielectric loss are 182.7 and 0.0024 separately，which presents excellent properties and can basically meet the requirements of phased array applications.