Abstract
The figure-of-merits of ferroelectrics for transducer applications are their electromechanical coupling factor and the operable temperature range. Relaxor-PbTiO3 ferroelectric crystals show a much improved electromechanical coupling factor k33 (88~93%) compared to their ceramic counterparts (65~78%) by taking advantage of the strong anisotropy of crystals. However, only a few relaxor-PbTiO3 systems, for example Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3, can be grown into single crystals, whose operable temperature range is limited by their rhombohedral-tetragonal phase transition temperatures (Trt: 60~120 °C). Here, we develop a templated grain-growth approach to fabricate <001>-textured Pb(In1/2Nb1/2)O3-Pb(Sc1/2Nb1/2)O3-PbTiO3 (PIN-PSN-PT) ceramics that contain a large amount of the refractory component Sc2O3, which has the ability to increase the Trt of the system. The high k33 of 85~89% and the greatly increased Trt of 160~200 °C are simultaneously achieved in the textured PIN-PSN-PT ceramics. The above merits will make textured PIN-PSN-PT ceramics an alternative to single crystals, benefiting the development of numerous advanced piezoelectric devices.
Highlights
The figure-of-merits of ferroelectrics for transducer applications are their electromechanical coupling factor and the operable temperature range
We used the template grain growth (TGG) method to fabricate -textured 0.19Pb(In1/2Nb1/2)O3–xPb(Sc1/2Nb1/2)O3–(0.81−x)PbTiO3 (PIN–PSN–PT) ceramics (x = 0.44–0.49), since our previous research found that the Trt of this solid solution was in the range of 210–240 °C28,29, offering more freedom for Trt tailoring by the templates
In the following text, all textured PIN–PSN–PT ceramics were sintered with the addition of CuO and B2O3
Summary
The figure-of-merits of ferroelectrics for transducer applications are their electromechanical coupling factor and the operable temperature range. The above merits will make textured PIN-PSN-PT ceramics an alternative to single crystals, benefiting the development of numerous advanced piezoelectric devices Perovskite ferroelectric ceramics, such as lead zirconate titanate (PZT), are the mainstay materials for piezoelectric transducers owing to their high electromechanical properties[1,2]. It has been observed that the -oriented rhombohedral Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN–PT) and Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIN–PMN–PT) (hereafter named relaxor-PT) crystals possess a very high electromechanical coupling factor k33 of 88–93%, which is superior to those of state-of-the-art PZT ceramics (65–78%)[7,8] Due to their enhanced k33, PMN–PT crystals have been commercialized in medical imaging transducers, showing greatly broadened bandwidth and enhanced sensitivity when compared to transducers based on PZT ceramics (e.g., one single-crystal transducer was reported to have the ability to cover the frequency range of two PZT ceramic transducers), offering significant advantages in penetration and imaging resolution[9]. Compositional segregation during crystal growth from melts hinders the application of relaxor-PT crystals for large-size piezoelectric transducers, e.g., low-frequency transducers, since it is difficult to obtain large relaxor-PT crystals with acceptable fluctuations in composition and electromechanical properties
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