Preparation and characterization of Si-doped barium titanate nanopowders and ceramics

Si-doped barium titanate nanopowders and ceramics were prepared through the sol-gel process. The powders and ceramics were characterized by methods of XRD, SEM and TEM. The dielectric properties of the ceramics were also determined. The results indicated that the powders were nanopowders and they were all cubic BaTiO3 phase with the concentration of Si <= 5.0 mol%. When the concentration of Si increased to 10.0 mol%, another phase of Ba2TiSi2O8 appeared. After sintering, the cubic BaTiO3 phase was transformed into tetrahedron BaTiO3 phase. Si doping with low concentration resulted in improving grain growth and reduced dielectric loss. As the sintering temperature increased, the dielectric properties of the ceramics decreased. BaTiO3 ceramics doped with Si all had a small peak at room temperature in epsilon-T cures. Specially, the ceramic doped with 0.3 mol% Si had evident double peaks, the maximum room temperature permittivity (4081) and the minimum dielectric loss (0.004). (C) 2008 Elsevier B.V. All rights reserved.