Large strain under low driving field in lead-free relaxor/ferroelectric composite ceramics |
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| Authors: | Pengyuan Fan Yangyang Zhang Yiwei Zhu Weigang Ma Kai Liu Xueting He Mohsin Ali Marwat Bing Xie Ming Li Haibo Zhang |
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| Affiliation: | 1. School of Materials Science and Engineering, State Key Laboratory of Material Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan, China;2. Information Engineering Institute, Huanghe Science and Technology College, Zhengzhou, China;3. Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham, Nottingham, UK |
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| Abstract: | 0.75(Na0.5Bi0.5)TiO3–0.25SrTiO3 lead-free incipient piezoceramic is a promising candidate for actuator applications due to their large reversible electromechanical strains at the relatively low driving field of 40 kV/cm. In order to further reduce the driving field of 0.75(Na0.5Bi0.5)TiO–0.25SrTiO3 relaxor ceramic to meet the requirements for real actuators application, the relaxor/ferroelectric (RE/FE) 0-3 composite ceramics method was employed. The polarization and strain behaviors were examined as a function of the weight ratio of the relaxor/ferroelectric phases. It was found that 90 wt% 0.75(Na0.5Bi0.5)TiO3–0.25SrTiO3/10 wt% 0.96(Na0.84K0.16)1/2Bi1/2TiO3–0.04SrTiO3 RE/FE 0-3 type composite samples provided a high unipolar strain of 0.25% and the corresponding large-signal piezoelectric coefficient, d*33 of 833 pm/V at 30 kV/cm, which are 32% higher than the values of the pure 0.75(Na0.5Bi0.5)TiO3–0.25SrTiO3. The enhanced electric-field-induced strain at relatively lower field was attributed primarily to the reduction in the RE-FE phase transition electric field. It was also found that the RE/FE composite ceramics exhibited significantly reduced frequency dependence in the unipolar strain behavior at room temperature. |
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| Keywords: | composites lead-free ceramics polarization relaxors strain |
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