Dielectric temperature stability of Nb-modified Bi0.5(Na0.78K0.22)0.5TiO3 lead-free ceramics

Abstract In this study, the phase structure, microstructure and dielectric properties of Bi0.5(Na0.78K0.22)0.5(Ti1-xNbx)O3 lead-free ceramics prepared by traditional solid phase sintering method were studied. The second phase pyrochlore bismuth titanate (Bi2Ti2O7) was produced in the system after introduction of Nb5+. The dielectric constant of the sample (x = 0.03) sintered at 1130 °C at room temperature reached a maximum of 1841, and the dielectric loss was 0.045 minimum. It had been found that the K+ and Nb5+ co-doped Bi0.5Na0.5TiO3 (BNT) lead-free ceramics exhibited outstanding dielectric-temperature stability within 100–400 °C with Tcc ≤±15%. Result of this research provides a valuable reference for application of BNT based capacitors in high temperature field.