The influence of the distribution of Cu-rich phase on the micromorphology and dielectric properties of BaTiO3 ceramics

The (1-x)BaTiO3-xCuO ceramics (x = 0, 0.5, 1.0, 1.5 and 2.0 wt%) were prepared by the traditional solid-state reaction method. The influence of the distribution of Cu-rich phase on the microscopic morphology, dielectric and complex impedance of BaTiO3 was studied. All samples show tetragonal phase structure. The images of SEM and EDS show that different amounts of CuO result in diverse distribution of Cu element at the grain boundary. The Cu element is concentrated in the grain boundary in a continuous network structure for x = 1.0 wt% and x = 2.0 wt%. And the Cu elements are mainly distributed in the punctate structure at triple junction for x = 1.5 wt%. Due to the pinning effect of Cu-rich phase at the triple junction, the grain of the BaTiO3 is refined. Not only is it beneficial to increase the permittivity and reduce the dielectric loss, but also improve the frequency stability of the dielectric performance at low frequency. In addition, the impedance analysis shows that the resistance and activation energy of conductivity of (1-x)BaTiO3-xCuO ceramics depend on the synergistic effect of the grain size and Cu-rich phase at the grain boundary. The smaller grain and the more Cu-rich phase at grain boundary, the greater resistance and activation energy of conductivity.

Automated summary

The addition of CuO improves the microstructure of BaTiO3, enhancing its dielectric properties and frequency stability.