Influence of Composition on Properties of BNT-BT Lead-Free Piezoceramics

Lead-free piezoelectric ceramics of (Bi1/2Na1/2)TiO3-BaTiO3(BNT-BT) were prepared by the conventional piezoelectric ceramic preparation technique (free air atmosphere sintering). The influence of BaTiO3 additive amount and La2O3 additive amount on the properties of BNT-BT lead-free piezoceramics were investigated. The results show that the dielectric constant(ɛ) and piezoelectric strain constant (d33) of materials start increasing and then decreasing while BaTiO3 additive amount increasing, the ɛ and d33 of materials have maximum value (ɛ = 1650, d33 = 120 PC · N−1) while x (BaTiO3) = 0.06 mol. The ɛ and d33 of materials start increasing and then decreasing while La2O3 additive amount increasing, the ɛ and d33 of materials have maximum value (ɛ = 1684, d33 = 153 PC · N−1) while w(La2O3) = 0.3%. The influence of La2O3 additive amount on the microstructure of BNT-BT piezoelectric ceramics was analysed by SEM (scanning electron microscope). The influence mechanism of La2O3 additive amount on the properties of BNT-BT piezoelectric ceramics was discussed. The BNT-BT ceramics with optimum comprehensive properties were obtained.