Enhanced piezoelectric properties and depolarization temperature in NBT-based ceramics by doping BT nanowires

(Na_0.5Bi_0.5)TiO₃-(K_0.5Bi_0.5)TiO₃–BaTiO₃ ternary ceramic exhibits excellent piezoelectric properties, but its depolarization temperature is a longstanding obstacle for their practical applications. The improvement of depolarization temperature of (Na_0.5Bi_0.5)TiO₃-based ceramics is usually companied by deterioration of piezoelectric properties. In this study, we use BaTiO₃ nanowires to replace BaTiO₃ solution in off-MPB 0.88(Na_0.5Bi_0.5)TiO₃-0.06(K_0.5Bi_0.5)TiO₃-0.06BaTiO₃ ceramic. A narrower peak in tanδ-T curves is obtained and the depolarization temperature T_d increased from 95 °C to 133 °C after BaTiO₃ nanowires substituting for BaTiO₃ solution. The promotion of T_d is thought to be associated with that the BaTiO₃ nanowires may pin the domain wall and suppress the dispersion of temperature induced FE-RE (AFE) phase transition. Meanwhile, the piezoelectric constant d₃₃ enhanced from 105 to 192 pC/N simultaneously due to the formation of MPB phase structure and high ε₃₃P_r value. The results proposed that the piezoelectric properties and depolarization temperature can be simultaneously improved in (Na_0.5Bi_0.5)TiO₃-based ceramics by doping BaTiO₃ nanowires into appropriate basic materials.