Journal of Inorganic Materials, Volume. 40, Issue 3, 297(2025)
Potassium-sodium niobate (K0.5Na0.5NbO3) based piezoelectric ceramics are considered the most potential lead-free piezoelectric ceramics due to their excellent piezoelectric coefficient (d33) and high Curie temperature (TC). However, the temperature stability of its d33 is poor in comparison with the Pb-based piezoelectric ceramics. To solve this problem, (K0.5Na0.5)0.96Li0.04(Nb0.95Sb0.05)O3-(Bi0.5Na0.5)ZrO3 (KNLNS-BNZ) piezoelectric ceramic with a single tetragonal phase (T phase) was designed and prepared by the conventional solid-state sintering method and texture engineering. It was found that KNLNS-BNZ-based textured ceramic with T phase at room temperature not only possessed a good piezoelectric coefficient (d33=256 pC∙N-1) and a longitudinal electromechanical coupling coefficient (k33=34%), but also exhibited excellent temperature stability of d33 and k33 in comparison to the non-textured ceramics. The change rates of d33 and k33 for KNLNS-BNZ-based textured ceramics were 12% and 4% with the measured temperature of 25-250 ℃, respectively. In addition, the 1-3 type transducer composed of KNLNS-BNZ-based textured ceramics and epoxy resin was also prepared and investigated. This 1-3 type transducer not only exhibited a large bandwidth (BW=61.2%) and excellent signal strength (fc=1 MHz), but also showed excellent temperature stability. As the measured temperature increased to 100 ℃, its bandwidth BW and center frequency fc were 58.7% and 0.94 MHz, whose rates of change were 4% and 6% in comparison to the results measured at room temperature, respectively. All these results show that KNLNS-BNZ lead-free piezoelectric ceramics have good piezoelectric properties and excellent temperature stability, and the 1-3 type transducer prepared by KNLNS-BNZ can provide reference for the practical application of new lead-free piezoelectric ceramics.
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Tianyu GAO, Dong LIU, Sixue ZHAO, Wei DENG, Boping ZHANG, Lifeng ZHU.
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Received: Oct. 8, 2024
Accepted: --
Published Online: Apr. 24, 2025
The Author Email: ZHAO Sixue (zhaosixue@whut.edu.cn), ZHU Lifeng (zhu@ustb.edu.cn)