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 ε−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).