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21.
Michael J. Brova Beecher H. Watson III Rebecca L. Walton Elizabeth R. Kupp Mark A. Fanton Richard J. Meyer Jr. Gary L. Messing 《Journal of the American Ceramic Society》2020,103(9):4794-4802
This study explores sintering and piezoelectricity of ZnO-doped perovskite Pb(In1/2Nb1/2)O3-Pb(Zn1/3Nb2/3)O3-PbTiO3 (PIN-PZN-PT) ceramics. The enhanced densification of ZnO-doped PIN-PZN-PT is attributed to the formation of oxygen vacancies by the incorporation of Zn2+ into the perovskite B-site and increased rate of bulk diffusion relative to undoped PIN-PZN-PT. Incorporation of Zn2+ into the perovskite lattice increased the tetragonal character of PIN-PZN-PT as demonstrated by tetragonal peak splitting and increased Curie temperature. Sintering in flowing oxygen reduced the solubility of Zn2+ in the perovskite lattice and resulted in rhombohedral PIN-PZN-PT. Sintering in oxygen prevented secondary phase formation which resulted in a high-piezoelectric coefficient (d33 – 550 pC/N), high-coercive field (Ec – 13 kV/cm), and high-rhombohedral to tetragonal phase transition temperature (Tr-t – 165°C). We conclude that ZnO-doped PIN-PZN-PT ceramics are excellent candidates for high-power transducer applications. 相似文献
22.
Small-scale wind energy harvesting from vortex-induced vibrations (VIV) has been introduced in recent years as a renewable power source for microelectronics and wireless sensors. Previous studies have focused on modeling and optimizing the VIV-based piezoelectric energy harvester (VIVPEH) structures and simplified the complicated interface circuits as pure resistors with an alternating current (AC) output. In practice, an AC output is required to be transformed into a direct current (DC) followed by further regulations before being used for real applications. Incorporating the rectification and regulation, traditional theoretical and numerical models will become extremely cumbersome and even impossible. To address this issue, this work proposes an equivalent circuit model (ECM) for a typical VIVPEH. The Scanlan-Ehsan aerodynamic force model is employed to describe the fluid-structure interaction. Wind tunnel experiments are carried out to validate the derived model. The performances of the VIVPEH with AC and DC interface circuits are subsequently analyzed and compared to understand the influences of these circuits on the operational wind speed bandwidth, power output, vibration amplitude, and electrical damping. 相似文献
23.
为更好的预测驰振压电能量收获机的性能,首先建立了等效电路仿真模型(ECM)并通过实验验证,最大误差不超过10%。采用该方法分析了被动湍流控制(PTC)下圆柱驰振压电能量收集的仿真模型,且该方法可将驰振能量转化系统的质量-弹簧-阻尼(M-C-K)控制方程中各参数用等效电路的电子元件来表示,从而可以分析过往仿真手段所不能解决的直流电路耦合问题。其次,从能量收集效率角度分析了交流-直流等效电路中临界风速(Ucr)随外接载荷的变化规律,及输出电压与功率随不同风速和外界载荷的变化规律。结果表明,交流电路中Ucr随载荷的增大先增大后减小,直流电路中Ucr随载荷的增大逐渐减小。当风速达到Ucr的最大值时,驰振在任一电阻下均会发生。U≥Ucr时,驰振出现锁定现象,输出电压和功率均随着风速的增大而增大。当风速过大时,增长率有减小趋势。输出电压均随着电阻的增大而增大,功率随电阻的增大先增大后减小。相比于交流电路,直流电路的最佳负载由1.1 MΩ提高到2.0 MΩ,同时功率峰值从0.08 mW降低到0.04 mW。 相似文献
24.
Raziye Hayati Mohammad Fayazi Hadi Diargar Mohammad Kaveh Lobat Tayebi 《International Journal of Applied Ceramic Technology》2020,17(4):1891-1898
In this study, lead-free (1 − x)Ba(Zr0.2Ti0.8)O3 − x(Ba0.7Ca0.3)TiO3 compositions are synthesized via conventional solid oxide route, and the ceramics are fabricated with normal sintering in air. The effects of composition fluctuations on dielectric, piezoelectric, and mechanical properties are investigated. The phase structure and the microstructure are analyzed with X-ray diffraction and scanning electron microscopy. The best dielectric and piezoelectric properties of εr = 11 207 and d33 = 330 pC/N were obtained for BZT−0.35BCT and BZT−0.5BCT ceramics, respectively. The mechanical behavior—in terms of Vickers hardness and compressive and flexural strengths—was investigated, and the best mechanical behavior was found in the vicinity of the phase transition boundary with x values between 0.5 and 0.6. 相似文献
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26.
Hao Chen Jie Xing Jingwen Xi Tao Pu Hong Liu Jianguo Zhu 《Journal of the American Ceramic Society》2021,104(12):6266-6276
The Ag-Pd internal electrode of multilayer piezoelectric ceramics needs to be sintered below 1000°C, and lead wires and components need to be welded with lead-free solder at 260°C. PNN–PMW–PZT–xSr piezoelectric ceramics with high Curie temperature (Tc > 260°C) were synthesized at a low sintering temperature (960°C) to meet the requirements of multilayer piezoelectric devices. The relationship between structures (phase, domain, and microstructures) and electrical properties (piezo/ferroelectric properties, and dielectric relaxation) in the Sr2+ substituted ceramics was investigated. Rietveld refinement and Raman spectra show that Sr2+ substitution can cause the phase change and increase the force constant of [BO6] octahedron. The piezoelectric response increases with increasing the content of the tetragonal phase (CTP) in the rhombohedral-tetragonal (R-T) coexisted ceramics. The ceramics with 0.6 mol% Sr2+ substitution have minimum activation energy for domain wall movement (Ea) of 0.0362 eV which favors the formation of nanometer-sized domains, and possess excellent electrical properties (d33 = 623 pC/N, d33* =783 pm/V, Tc =295°C). The higher the CTP, the lower the Ea. The lower Ea favors the rotation of polarization direction and extension, and is beneficial to the generation of the nanometer-size domains, resulting in high piezoelectric properties. 相似文献
27.
《Ceramics International》2021,47(21):30439-30447
Bismuth titanate (Bi4Ti3O12, BIT) exhibits a high Curie temperature and anisotropic electrical performance owing to its layered perovskite structure, and hence, it is an important ferroelectric material for high-temperature piezoelectric applications. It is crucial to understand the effects of the anisotropy in BIT-based ferroelectrics for developing novel high-temperature piezoelectric materials. In this study, a highly textured BIT ceramic was fabricated using the tape-casting technique from highly grain-oriented BIT platelets prepared by the molten salt method. The textured BIT ceramic showed a dense microstructure and high grain orientation along the (00l) plane with a texturing degree F00l = 0.86. It exhibited significant anisotropy in the electrical properties along the directions parallel and perpendicular to the axis of the tape-casting plane. Double ferroelectric hysteresis P–E loops and normal ferroelectric P–E loops were observed in the parallel and perpendicular samples, respectively. In addition to the layered crystal structure and domains, the anisotropy in the arrangement of the oxygen vacancy defects and their transport in the structure led to a significant anisotropy in the ferroelectric properties of the textured BIT ceramics. This work demonstrates the anisotropic arrangement of the oxygen vacancy defects and its effect on the electrical properties of high-temperature bismuth layer-structured ferroelectrics. 相似文献
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为了研究压电陶瓷驱动器的驱动性能,分析了以PZT-5H为驱动元件的叠堆型驱动器,采用简化的等效器件建立了电学模型。基于压电陶瓷材料的机电耦合特性运用ANSYS有限元分析软件对叠堆型驱动器进行了计算分析,得出输入电压与输出位移呈近似线性关系,通过控制压电陶瓷两端电压来控制其位移。仿真结果验证了此方案的有效性和可行性。该驱动器在自适应弹药上具有潜在的应用价值,可为弹头的偏转驱动装置设计提供参考。 相似文献