High dielectric constant and good thermal stability from −55 °C to 450 °C in BaTiO3-based ceramics

An ultrahigh-temperature X-R type dielectric material, BaTiO3-Na0.5Bi0.5TiO3-Nb2O5-ZnO-Glass with Sm2O3 addition, was successfully prepared. The effects of Sm2O3 content on the phase structure, dielectric and electric properties of ceramics were investigated. Sm ion can substitute for both Ti and Ba-sites, which leads to the decrease of spontaneous polarization and dipolar polarization. As a result, the temperature stability in εr of sample is improved obviously. The 0.2 mol% Sm2O3-doped sample shows the optimal dielectric properties (εr=2458; tan δ=1.80%; ∆C/C20 °C<±15%, −55 °C to 450 °C), which satisfies EIA X-R specification. This material with particular focuses on enhancing the upper temperature limit to 450 °C, while still maintaining high dielectric constant.