The enhanced piezoelectric performance of Bi1/2Na1/2TiO3–BaTiO3 ceramics by Ba0.77Ca0.23TiO3 substitution

In this study, lead-free (1−x)Bi0.47Na0.47Ba0.06TiO3–xBa0.77Ca0.23TiO3 (BNBT–xBCT, x = 0–0.12) ceramics were fabricated by ordinary ceramic sintering technique. The results show that Ba0.77Ca0.23TiO3 (BCT) has diffused into Bi0.47Na0.47Ba0.06TiO3 (BNBT) lattices to form a new solid solution BNBT–xBCT. Moderate substitution of BCT in BNBT–xBCT (x ⩽ 0.01) ceramics can enhance the piezoelectric and ferroelectric properties; meanwhile, depolarization temperature of the ceramics does not decrease. BNBT–0.01BCT ceramic exhibits the best piezoelectric properties and strongest ferroelectricity: piezoelectric coefficient d33 = 178 pC/N; electromechanical coupling factors kt = 50% and kp = 27%; quality factor Qm = 131; remnant polarization Pr = 36 μC/cm2; coercive field Ec = 24.5 kV/cm. The piezoelectric properties, ferroelectric characteristics and depolarization mechanism of the ceramics are investigated and discussed.

► Moderate BCT enhances the piezoelectric and ferroelectric properties of BNBT–xBCT.
► Depolarization temperature of the ceramics does not decrease with BCT content.
► The properties of BNBT–0.01BCT: d33 = 178 pC/N; kt = 50% and kp = 27%; Qm = 131.
► Depolarization mechanism is discussed.