The dielectric properties and microstructure of BaTiO3 ceramics with ZnO-Nb2O5 composite addition

ZnNb2O6 powders were prepared by solid state reaction method and doped into BT. The doped cation ions diffused into the BT crystal lattice, inducing diffuse phase transition and leading to broadened and flattened dielectric constant peaks especially in the low-temperature zone. When the doping concentration was below 6 wt.%, ceramics showed regular microstructures; when it reached 7.5wt.%, the Ba2Ti5O12 phase was found and it showed flake structure. With further increase of ZnNb2O6, the flake structure disappeared and the grain size markedly decreased. The decreased grain size was very effective to improve the breakdown strength. (C) 2015 Elsevier B.V. All rights reserved.