Hard Piezoelectric Properties of MnCO3-Doped Lead-Free BiFeO3-BaTiO3 Ceramics with High Curie Temperature

초록

Lead-free BiFeO3-BaTiO3 (BF-BT) ceramics show high potential for piezoelectric sensors, actuators, and high-power transducers owing to their excellent piezoelectric properties and high Curie temperatures (T-C). Hard piezoelectric material used in high-power transducer applications must exhibit a high mechanical quality factor (Q(m)), high coercive field (E-C), high T-C, and low dielectric loss (tan delta). Herein, the effects of doping in BF-BT ceramics with the hard acceptor dopant Mn2+ are investigated to enhance their hard piezoelectric properties. The 0.8Bi(1.02)(Fe1-xMnx)O-3-0.2BaTiO(3) (x = 0, 0.005, 0.01, 0.015, and 0.02) ceramics are prepared using solid-state reaction and water-quenching processes. The increasing of the Mn2+ content in BF-BT ceramics boosts the piezoelectric charge sensor coefficient (d(33)), Q(m), T-C, planar piezoelectric coupling factor (k(p)), E-C, and internal bias field (E-i), reaching their maximum values at x = 0.01 (d(33) = 74 pC/N, Q(m) = 757, T-C = 652 degrees C, k(p) = 0.26, E-C = 65 kV/cm, and E-i = 6.2 kV/cm) with the lowest loss (tan delta = 0.009). Then, the hard piezoelectric properties deteriorate gradually with an increasing Mn content. The ferroelectric domain structure and dynamics are compared to defect-related ferroelectric and piezoelectric properties. These results show that the hard acceptor Mn2+ in the BF-BT ceramics improves the performance of lead-free ceramics for high-power piezoelectric transducers in high-temperature environments.

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