Phase structure and electrical properties of ternary PSN-PMN-PT ceramics and their applications in ultrasonic transducers

In this work, a series of xPSN-(1 - x - y)PMN-yPT (x = 0.06 - 0.43, y = 0.32 - 0.42) ternary ceramics with different phase structures were synthesized by the solid state reaction method, and the specific phase structure, electrical properties and thermal stability as a function of compositions were investigated. It is found that with the increasing PT content, the phase transition sequence is MC + R -* MC + MA + R -*MC + T for the ceramics with the same PSN content. Meanwhile, with the increasing PSN content, the MPB compositions shift to higher PT content. The maximum d33 value for x = 0.06, 0.15, 0.29 and 0.43 ceramics occurs at y = 0.35, 0.37, 0.39 and 0.40, respectively, which are dominated by T phase and coexist with a small fraction of MC phase and the corresponding d33 value is 665, 620, 585 and 650 pC/N. From 30 degrees C to the depolarization temperature Td of each ceramic, the variation rate of d33 is 13%, 7%, 5%, and 15%, respectively, demonstrating that these ceramics have a good thermal stability. In addition, the 0.06PSN-0.59PMN-0.35PT ceramic with the highest d33 is selected as an active element of ultrasonic transducer, and the ultrasonic transducer with a center frequency of 4.65 MHz was produced. The -6 dB bandwidth and two-way insertion loss are 77.4 % and -21.45 dB, respectively. This work has important implications for the further development of high-performance PT based ferroelectrics.