ZnO-doped BaTiO3-Na0.5Bi0.5TiO3-Nb2O5-based ceramics with temperature-stable high permittivity from –55 °C to 375 °C

Abstract

A lead-free, high-permittivity and high-temperature X–R type dielectric material was successfully prepared in ZnO-doped BaTiO3-Na0.5Bi0.5TiO3-Nb2O5(BNN)- based system. The effects of ZnO content on the phase structure, electric and dielectric properties of the ceramics were investigated. Results indicate that ZnO addition plays a critical role in increasing permittivity and improving the temperature stability. The 5wt% ZnO-doped sample shows the optimal dielectric performance (εr=2404; tanδ=1.76%; ΔC/C20°C<±13%) that satisfies EIA X-R specification. In particular, the ceiling working temperature is significantly enhanced from 200°C to 375°C and the permittivity is increased to 2404 by doping ZnO. These results suggest that these materials are promising candidates for preparing miniaturized ultra-broad temperature multilayer ceramic capacitors.