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High electrostrain with high Curie temperature in BiFeO3-BaTiO3-based ceramics
摘要： Here, we report a high unipolar electrostrain (0.45%) with a high Curie temperature (TC = 410 °C) in lead-free (1-x)(0.67BiFeO3–0.33BaTiO3)-xSr0.8La0.1□0.1TiO2.95 (□ represents the A-site vacancy) piezoceramics with x = 0.02. Sr0.8La0.1□0.1TiO2.95 was introduced to construct a relaxor ferroelectric state. The obtained unipolar strain was thermally stable, and the variation from room temperature to 100 °C was only 10%. Systematic electromechanical and Raman spectra measurements revealed a composition driven phase transition from classical ferroelectric to relaxor ferroelectric phases and distorted internal stress field. This work provides a novel strategy to obtain high electrostrain in high temperature piezoceramics.
关键词： Electrostrain,BiFeO3-based ceramics,High TC,Vacancy
更新于2025-11-14 17:28:48
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Electromechanical Properties of Ferroelectric (NaKLi)(NbTa)O <sub/>3</sub> –CaZrO <sub/>3</sub> Ceramics
摘要： Electromechanical Properties of Ferroelectric (NaKLi)(NbTa)O3–CaZrO3 Ceramics. The effect of CaZrO3 to electric and mechanical properties of (Na0.47K0.51Li0.02)(Nb0.8Ta0.2)O3 was investigated. With increment of CaZrO3, the crystal structure of (Na0.47K0.51Li0.02)(Nb0.8Ta0.2)O3 changed from the mixture of ferroelectric orthorhombic and rhombohedral phases to paraelectric pseudo-cubic phase. On the way of transition from ferroelectric to paraelectric phases, the composition range showing the mixture of ferroelectric/paraelectric phases with a structure of core/shell was revealed with an advent of relatively large strain behavior. The shell phase formed via solid-state diffusion of Nb, Ta, Na, K ions between (Na0.47K0.51Li0.02)(Nb0.8Ta0.2)O3 and CaZrO3 particles, followed by its subsequent solution process with mixing a Ta-rich perovskite with Ca and Zr ions. In contrast, the core phase formed via a solution-precipitation process, resulting in a Ta-depleted ferroelectric perovskite. Energy-dispersive X-ray analysis showed that core was a Nb-rich ferroelectric phase and the shell was a Ta-rich paraelectric phase with Ca and Zr ions at room temperature. This structure implies an interaction between straining behaviors in the core and shell phases under an electric field, leading large deformation in macro-scale.
关键词： Piezoelectric Properties,Electrostrain,(NaKLi)(NbTa)O3,CaZrO3,Ferroelectric Material
更新于2025-09-19 17:15:36
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Large electrostrain and structural evolution in (1-x)[0.94Bi0.5Na0.5TiO3-0.06BaTiO3]-xAgNbO3 ceramics
摘要： lead-free system formulated as (1-x)[0.94Bi0.5Na0.5TiO3-0.06BaTiO3]-xAgNbO3 exhibits an electrostrain of 0.50 % at 80 kV/cm and a maximum d33* of 721 pm/V at 60 kV/cm for x=0.3. The incorporation of AgNbO3 shifts the relaxor-ferroelectric phase transformation temperature (TF-R) to room temperature and lowers the energy barrier of the field-induced phase transformation. Furthermore, the in-situ electric field dependent high-energy synchrotron X-ray diffraction (SXRD) technique reveals that the sample x=0.03 transforms from dominant P4bm phase to a phase mixture of R3c + P4mm at 55 kV/cm during the electric field loading, and returns to initial dominant P4bm phase at 15 kV/cm during the unloading cycle of the electric field. Furthermore, it can be demonstrated that the electric field induced-phase transition in NBTBT-3AN occurs in the whole sample, rather than in the single direction of electric field. Therefore, the electrocstrain in NBTBT-3AN is more uniform, which would be beneficial to its actuator applications.
关键词： Electrostrain,Bi0.5Na0.5NbO3,Piezoelectrics,AgNbO3
更新于2025-09-10 09:29:36