Sintering and Dielectric Properties of Sr-Rich Barium Strontium Titanate (BST) Ceramics Fabricated by a Mixed-Phase Method

Ba 1-x Sr x TiO 3 (x=0.6 to 0.9 interval of 0.1) ceramics were developed by a BT sol-assisted sintering technology with a mixed-phase sintering from the mixture of BT and ST powders synthetized by a solid-state reaction method. The sintering behavior and dielectric properties of the ceramics were investigated. Results show that the sintering activity of the ceramics becomes worse and worse when increased the strontium content, and the sintering condition have a remarkable effect on the density of the ceramics. Dense ceramics were obtained when sintered at 1280°C for 8h with a relatively density of above 94%. The composition had a strong effect on the dielectric properties, while the sintering schedule had a little influence on the dielectric temperature spectrum of the BST ceramics. The Ba 1-x Sr x TiO 3 (x=0.9) ceramic with dielectric constant～335, loss tangent～0.000625 at 1.85 GHz and 20°C, and good temperature stability of dielectric constant above the room temperature is attained.