Enhanced piezoelectric performance of Cr/Ta non-equivalent co-doped Bi4Ti3O12-based high-temperature piezoceramics

In this study, (Cr1/3/Ta2/3) non-equivalent co-doped Bi4Ti3O12 (BIT) ceramics were prepared to solve the problem that high piezoelectric performance, high Curie temperature, and high-temperature resistivity could not be achieved simultaneously in BIT-based ceramics. A series of Bi4Ti3-x(Cr1/3Ta2/3)xO12 (x = 0-0.04) ceramics were synthesized by the solid-state reaction method. The phase structure, microstructure, piezoelectric performance, and conductive mechanism of the samples were systematically investigated. The B-site non-equivalent co-doping strategy combining high-valence Ta5+ and low-valence Cr3+ significantly enhances electrical properties due to a decrease in oxygen vacancy concentration. Bi4Ti2.97(Cr1/3Ta2/3)0.03O12 ceramics exhibit a high piezoelectric coefficient (d33 = 26 pC<middle dot>N-1) and a high Curie temperature (TC = 687 degrees C). Moreover, the significantly increased resistivity (rho = 2.8x106 Omega<middle dot>cm at 500 degrees C) and good piezoelectric stability up to 600 degrees C are also obtained for this composition. All the results demonstrate that Cr/Ta co-doped BIT-based ceramics have great potential to be applied in high-temperature piezoelectric applications.