Improved in situ high temperature piezoelectric performance of BiScO3-PbTiO3-Pb(Sn1/3Nb2/3)O3 ceramics for actuator applications

In this paper, new series of high temperature piezoelectric ceramics consisting of (0.975-x)BiScO3-xPbTiO3-0.025 Pb(Sn1/3Nb2/3)O3 (BS-xPT-0.025PSN), have been fabricated and investigated in detail. The phase structure analysis and electrical properties characterization at room temperature demonstrate the MPB composition is BS-0.62PT-0.025PSN with the optimum piezoelectric performance (d33 523 pC/N, large-signal d33* 734 p.m./V, and kp 54.6%), which are superior than the unmodified BS-PT ceramics. Interestingly, the in situ electromechanical coupling properties exhibits good stability with the variation lower 5% as the temperature increasing from room temperature to 300 °C and the d33* reaches the maxima of 1413 p.m./V at 200 °C, and remains 743 p.m./V even at 300 °C, showing the BS-0.62PT-0.025PSN ceramics potential for high temperature piezoelectric actuator application together with the Curie temperature of 418 °C and the high temperature annealing stabilities. Then a 10-layer stack-type piezoelectric actuator was designed and fabricated based on the BS-0.62PT-0.025PSN ceramics, which can be operated steadily up to 200 °C and produces a displacement of 24 μm under the driven electric field. The maximum displacement 32.4 μm of the actuator was obtained at the testing temperature of 150 °C, far more than that of the value at the room temperature. The BS-0.62 PT-PSN ceramics and their stack-type piezoelectric actuator maybe a strong supplement to satisfy the urgent demand for high temperature piezoelectric actuator.