Enhanced strain and low hysteresis with good fatigue resistance in barium titanate-based piezoelectric ceramics

In order to fulfill the demands of high strain and low hysteresis for high-precision displacement actuators, (0.925 − x)BaTiO₃–xSrTiO₃–0.075Ba(Zr_0.5Hf_0.5)O₃ (BT–xST–BZH, 0 ≤ x ≤ 0.30) ceramics are prepared in the study by traditional solid-state method. The rhombohedral–orthorhombic (R–O) phase boundary is constructed at 0.05 ≤ x ≤ 0.10 around room temperature. Due to the coexistence of R and O phases in the R–O phase boundary resulting in small domains and high domain wall density, excellent ferroelectric and strain properties including maximum polarization (P _max ~ 22.2 µC/cm²), residual polarization (P_r ~ 11.0 µC/cm²) and coercive field (E_c ~ 1.1 kV/cm) and large strain (S _max ~ 0.19%) with low hysteresis (H_ys ~ 6.3%) are obtained under 50 kV/cm in BT–0.10ST–BZH ceramic. Under lower excited electric field (E) 30 kV/cm, the excellent strain (S _max ~ 0.16%) and low hysteresis (H_ys ~ 8.2%) can also be obtained. Moreover, good fatigue resistance is also achieved in this compound, i.e. both bipolar and unipolar strain degradation are ~ 12.5% and the hysteresis is ~ 9.0% after 10⁶ cycles under an electric field of 40 kV/cm. These characteristics make BT–0.10ST–BZH ceramic likely to be used in high-precision displacement actuators.