Preparation and dielectric properties of BST-Mg2TiO4 composite ceramics

The 100(1 − y) wt%Ba1−xSrxTiO3–100y wt%Mg2TiO4 (BST-MT, 0.45 ≤ x ≤ 0.6, 0.3 ≤ y ≤ 0.7) composite ceramics were fabricated by mixing (Ba,Sr)TiO3 and Mg2TiO4 powders via a conventional ceramic processing technique. The sintering behavior, microstructures, and dielectric properties of composite ceramics were investigated. The dense BST-MT composite ceramics were obtained at a temperature range from 1350 to 1430 °C without forming the impurity phases. By adjusting the relative content of two components and the Ba/Sr ratio in (Ba,Sr)TiO3, an optimum ceramic composite with dielectric constant ∼76.5, loss tangent ∼0.0007 at 10 kHz and 20 °C, dielectric tunability ∼10.2% under a dc electric field of 20 kV cm−1 and good temperature stability of dielectric constant was attained.