Influence of Sb2O3 doping on the properties of KBT-NBT-BT lead-free piezoelectric ceramics

0.144(K_0.5Bi_0.5)TiO₃-0.85(Na_0.5Bi_0.5)TiO₃-0.006BaTiO₃ (KBT-NBT-BT) lead-free piezoelectric ceramics were prepared using a conventional solid state method. The influence of Sb₂O₃ doping on the crystal phase, surface microstructure and properties of the KBT-NBT-BT lead-free piezoelectric ceramics were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM) and other analytical methods. The results show that all compositions are of pure perovskite structure solid states. Sb₂O₃ doping does not influence the microstructure of KBT-NBT-BT lead-free piezoelectric ceramics obviously in the Sb₂O₃ doping range of 0.1–0.5 wt.%. Sb₂O₃ functions as a donor when doped small amount, while functions as a acceptor when doped large amount. The piezoelectric strain constant (d ₃₃) increases first and then decreases; the dielectric constant (ɛ₃₃^T/ɛ₀) and the dielectric loss (tanδ) decrease continuously when the amount of Sb₂O₃ dopant increases. When the doping amount of Sb₂O₃ is 0.1 wt.%, the KBT-NBT-BT piezoelectric ceramics with good comprehensive properties are obtained, whose d ₃₃, ɛ₃₃^T/ɛ₀ and tan δ are 147 pC/N, 1510 and 4.2%, respectively.