Study of BaTiO3-doped Bi2O3/ZnO varistor microstructure and its electrical characteristics

This study presents the characterization and optimization of BaTiO₃-doped ZnO-based varistors for electrical and electronic applications. The varistors were prepared using a conventional ceramic procedure and were sintered at a temperature of 1,000 °C with different concentrations of BaTiO₃ (0 and 3 mol%) added to the Bi₂O₃/ZnO-based varistor composition (99.5 mol% ZnO and 0.5 mol% Bi₂O₃). The results showed that the addition of BaTiO₃ led to the formation of various oxides and solid solutions, such as Bi1₂TiO₂₀, BaTiO₃, and (Bi₂O₃)_0.80 (BaO)_0.20. The dielectric constant and grain size decreased with increasing BaTiO₃ content, while the non-linearity coefficient, electric fields (Eb) increased, and dielectric loss (Tanδ) decreased. The optimized varistor contains 2 mol% BaTiO₃ and an electric field of 148.08 V/mm, which are superior to those of the BaTiO₃/Bi₂O₃/ZnO-based varistor. During this study, we were able to observe that a slight addition of BaTiO₃ will increase the breakdown voltage and the coefficient of nonlinearity and this will allow us to develop low-dimensional varistors and install them in the high-voltage domain.