Multi-phase coexistence and temperature-stable dielectric properties in BaTiO3/ZnO composite ceramics

BaTiO3:100xZnO composite ceramics with different ZnO particle sizes were prepared by using a conventional solid-state method. Phase constitution, microstructure and dielectric properties of BaTiO3:100xZnO composite ceramics are investigated. Compared to micrometer scaled ZnO particles, nanometer scaled ZnO particles tend to agglomerate at lower ZnO contents in the BaTiO3:100xZnO composite ceramics. The introduction of ZnO in BaTiO3 leads to the reduction of grain size, decrease of the tetragonality and shift of phase transition temperature. The optimum composition is BaTiO3 with 20 wt. % nanometer scaled ZnO particles, which has stable permittivity and low dielectric loss from -100 to 160 degrees C. The stable dielectric properties are proposed to be beneficiated from the stress induced multi-phase coexistence.