Novel TiO2·WO3 varistor system

The nonlinear electrical behavior and dielectric properties of TiO2-based ceramics with various WO3 contents have been investigated. It was found that the 0.25% WO3+99.75% TiO2 has an optimal nonlinear coefficient α of 9.6, a breakdown electrical field of 44.5 V mm−1, and an ultrahigh relative dielectric constant of 7.41×104 (measured at 1 kHz). The theory of defects in the crystal lattice was introduced to explain the nonlinear electrical behavior of the TiO2·WO3 system. A grain boundary barrier model that is analogous to the grain boundary defect model for ZnO varistors are introduced in the article. From this point, the nonlinear electrical behavior of the TiO2 system is explained.