Sinterability and dielectric properties of Ba0.55Sr0.4Ca0.05TiO3–CaTiSiO5–Mg2TiO4 composite ceramics

The composite ceramics of Ba0.55Sr0.4Ca0.05TiO3–CaTiSiO5–Mg2TiO4 (BSCT–CTS–MT) were prepared by the conventional solid-state route. The sintering performance, phase structures, morphologies, and dielectric properties of the composite ceramics were investigated. The BSCT–CTS–MT ceramics were sintered at 1100 °C and possessed dense microstructure. The dielectric constant was tailored from 1196 to 141 as the amount of Mg2TiO4 increased from 0 to 50 wt%. The dielectric constant and dielectric loss of 40 wt% Ba0.55Sr0.4Ca0.05TiO3–10 wt% CaTiSiO5–50 wt% Mg2TiO4 was 141 and 0.0020, respectively, and the tunability was 8.64% under a DC electric field of 8.0 kV/cm. The Curie peaks were broadened and depressed after the addition of CaTiSiO5. The optimistic dielectric properties made it a promising candidate for the application of tunable capacitors and phase shifters.

► The ceramics were prepared by solid-state method with nanometer BSCT powder.
► The low sintering temperature is due to the CaTiSiO5, nanometer powder and sintering aids.
► The addition of CaTiSiO5 improves the dielectric constant temperature stability.
► The excellent dielectric properties were ɛ = 141, tan δ = 0.0020, tunability = 8.64%.