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High electromechanical strain properties in SrTiO3?modified Bi1/2Na1/2TiO3?KTaO3 lead?free piezoelectric ceramics under low electric field
摘要： This study investigated the structures, dielectric, ferroelectric and piezoelectric properties of (0.99?x)Bi1/2Na1/2TiO3?0.01KTaO3?xSrTiO3 (BNT?KT?100xST, x = 0.20 ~ 0.235) lead?free piezoelectric ceramics. These piezoceramics were synthesized by conventional solid?state reaction method. As a consequence, a large electrical strain and normalized strain (d33* ≈ 793 pm/V) can be obtained even under 3 kV/mm as low electric field for BNT?KT?22.5ST ceramics. The phase transition between nonergodic relaxor (NER) and ergodic relaxor (ER) under electric field might be responsible for its large strain. It means that BNT?KT?100xST lead?free ceramics can be a promising candidate for actuator applications.
关键词： Phase transition,Lead-free,Ternary system,Piezoelectric ceramics,Relaxor
更新于2025-11-14 17:28:48
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Pseudocubic-based polymorphic phase boundary structures and their effect on the piezoelectric properties of (Li,Na,K)(Nb,Sb)O3-SrZrO3 lead-free ceramics
摘要： CuO-added 0.96(LixNa0.5-xK0.5)(Nb1-ySby)O3-0.04SrZrO3 ceramics were sintered at 1020oC for 6 h. Various crystal structures were synthesized in these specimens by controlling the Li2CO3 (x) and Sb2O5 (y) contents: pseudocubic, orthorhombic-pseudocubic polymorphic phase boundary (PPB), tetragonal-pseudocubic PPB, orthorhombic-tetragonal-pseudocubic PPB, and orthorhombic-tetragonal PPB structures. The pseudocubic structure developed in these specimens was similar to the R3m rhombohedral structure instead of the Pm3m cubic structure because the specimens with a pure pseudocubic structure showed good ferroelectric and piezoelectric properties. The piezoelectric properties of the specimens were influenced by their crystal structures. The specimen with the tetragonal-pseudocubic PPB structure showed the best piezoelectric properties because this structure was similar to the tetragonal-rhombohedral morphotropic phase boundary structure developed in Pb(Zr1-xTix)O3-based ceramics. In particular, the specimen with the tetragonal-pseudocubic PPB structure corresponding to x = 0.05 and y = 0.065 showed the largest d33 and kp values of 431 pC/N and 0.43, respectively.
关键词： K)(Nb,Piezoelectric properties,Polymorphic phase boundary structure,Sb)O3-SrZrO3-based lead free piezoelectric ceramics,Pseudocubic structure,Na,(Li
更新于2025-09-23 15:23:52
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Improved upconversion photoluminescence properties of 0.965K0.4Na0.58Li0.02Nb0.96Sb0.04O3–0.035Bi0.5K0.5ZrO3:0.25%Er/xIn lead-free piezoelectric ceramics with balanced piezoelectric coefficient and Curie temperature
摘要： A series of erbium- and indium-doped 0.965K0.40Na0.58Li0.02Nb0.96Sb0.04O3–0.035Bi0.5K0.5ZrO3:0.25%Er/xIn lead-free piezoelectric ceramics with upconversion photoluminescence (UCPL) properties were prepared by the conventional solid state reaction. A systematical investigation into the effects of In3+ doping on the structural, dielectric, ferroelectric, piezoelectric, and UCPL properties of the ceramics was carried out. The distribution of Er3+-sites could be modified by In3+ doping according to the analysis of UV–Vis-NIR absorption cross-section, resulting in improved piezoelectric and photoluminescence properties of the ceramics. The optimized comprehensive properties are performed by the x = 0.25% samples of which the piezoelectric coefficient d33 ~ 257 pC/N, Curie temperature TC ~ 273 °C, remanent polarization Pr ~ 12.5 μC/cm2, dielectric constant εr ~ 1551, and d33 ~ 257 pC/N which is the supreme piezoelectric coefficient achieved in KNN-based UCPL ceramics as of now. The results demonstrate that erbium and indium co-doped KNN-based ceramics may have potential applications in electro-optical devices.
关键词： Upconversion photoluminescence,Erbium and indium co-doping,Piezoelectric coefficient,Lead-free piezoelectric ceramics,Curie temperature
更新于2025-09-23 15:21:01
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Construction of high <i>T</i> <sub/>c</sub> BiScO <sub/>3</sub> -BiFeO <sub/>3</sub> -PbTiO <sub/>3</sub> and its enhanced piezoelectric properties by sintering in oxygen atmosphere
摘要： The high-temperature piezoelectric ceramics 0.36[(1 ? x)BiScO3-xBiFeO3]-0.64PbTiO3 was constructed by introducing BiFeO3 with a high Curie temperature (Tc ～ 830 °C) in the 0.36BiScO3-0.64PbTiO3 binary system. In terms of microstructure, low-melting BiFeO3 plays a role as a sintering aid, lowering the sintering temperature of the ceramic and signi?cantly increasing the grain size. At the same time, the crystal structure shifts from the initial morphotropic phase boundary to the tetragonal phase side, and the Tc increased gradually with increasing BiFeO3 content. Under the conventional air atmosphere sintering conditions, the Tc of the sample with x = 0.3 can reach ～500 °C, and the piezoelectric constant d33 is 125 pC/N. Compared with that, the d33 of the same composition sample sintered in an oxygen atmosphere is increased to 165 pC/N, which is mainly due to the decrease in the content of oxygen vacancies that helps to increase poling electrical ?eld. Moreover, the oxygen-sintered specimen exhibits an excellent thermal stability in a wide temperature range from room temperature to 450 °C, indicating that it is a promising candidate for ultra-high-temperature piezoelectric devices applications.
关键词： high-temperature piezoelectric ceramics,thermal stability,BiScO3-BiFeO3-PbTiO3,sintering in oxygen atmosphere,piezoelectric properties
更新于2025-09-11 14:15:04
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Higher permittivity of Ni-doped Lead Zirconate Titanate, Pb[(Zr0.52Ti0.48)(1-x) Nix]O3, ceramics
摘要： The paper reports highest obtained dielectric constant for Ni-doped Lead Zirconate Titanate [PZT, Pb(Zr0.52Ti0.48)O3] ceramics. The Ni-doped PZT ceramic pellets were prepared via conventional solid-state reaction method with Ni content chosen in the range 0-20 at.%. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy were employed to investigate the crystal structure of the prepared ceramics. The X-ray diffraction analysis indicated that the ceramic pellets had crystallized into tetragonal perovskite structure. A minute displacement of XRD peaks was detected in the diffraction spectra of Ni-doped PZT which when examined by size-strain plot (SSP) method revealed presence of homogenous strain that decreased with increase in concentration of Ni. In FTIR the maximum absorption at 597 cm-1, 608 cm-1, 611 cm-1, 605 and 613 cm-1 for Ni = 0, 5, 10, 15 and 20 at.%, respectively, confirmed the formation of perovskite structure in all the compositions and the slight shift suggests decrease in cell size on doping. The values of dielectric constant (ε￠) & tand as a function of frequency and temperature were measured for the prepared ceramics and it revealed highest ever reported dielectric constant for Ni - doped PZT with Ni = 5 at.%. The dielectric variation with temperature exhibited a diffused type ferroelectric–paraelectric phase transition for the doped samples. Also, the maximum dielectric constant value (??max) decreased with an increase in doping concentration of Ni while the phase transition temperature increased with increase in doping concentration. The estimated activation energy of different compositions was found to increase from 0.057 to 0.068 eV for x = 0.00 to x = 0.20 in ferroelectric phase. The piezoelectric, ferroelectric and magnetic properties were also investigated.
关键词： Piezoelectric ceramics,Dielectric,solid-state reaction,Ni-doping
更新于2025-09-10 09:29:36
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The effects of terbium oxide on phase transition and electronic properties of potassium-sodium niobate-based ceramics
摘要： Lead free piezoelectric ceramics 0.96K0.48Na0.52Nb0.96Sb0.04O3-0.04Bi0.5(Na0.82K0.18)0.5ZrO3-xmol%Tb4O7 (KNNS- BNKZ-xTb4O7) are prepared by solid state reaction method. The effects of Tb4O7 on phase transition, grain growth and electronic properties of the ceramics are studied. Tb4O7 (x (cid:1) 0.2) induces a phase transition from tetragonal-orthorhombic coexistence phases to pseudo-cubic one. Meanwhile, Tb4O7 could reduce grain size and lead to step-like grain growth. In addition, Tb4O7 could enhance the temperature stability of KNNS-BNKZ ceramics. For pure KNNS-BNKZ ceramics, the d33* and kp are reduced by 68.0% and 24.3%, respectively, from 30 (cid:3)C to 150 (cid:3)C. For the component x ? 0.1, they are reduced by 6.1% and 1.6%, respectively, in the same temperature range. This paper may have positive signi?cance for searching lead free piezoelectric ceramics with excellent temperature stable properties.
关键词： Piezoelectric ceramics,Phase transition,Lead free,Temperature stability
更新于2025-09-10 09:29:36
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An inverse approach to the characterisation of material parameters of piezoelectric discs with triple-ring-electrodes
摘要： For its usage in simulation-based design processes a precise knowledge of the employed material properties is inevitable. In the case of piezoelectric ceramics, the provided material parameters often suffer from large uncertainties and even inconsistencies since the standardised measurement procedure needs several specimens to determine a single set of material parameters. In contrast, the presented measurement set-up allows to calculate material parameters using one unique disc-shaped specimen with an optimised electrode topology. Using an inverse problem approach, fitting material parameters can be found using an optimisation procedure.
关键词： piezoelectric ceramics,Parameter identification,optimisation,inverse problem
更新于2025-09-10 09:29:36
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Structure and property of lead-free (K,Na)NbO3–(Bi1/2Na1/2)ZrO3–CaTiO3 piezoelectric ceramics
摘要： Simultaneous improvement of piezoelectricity and temperature stability is vital for developing high-performance KNN-based lead-free materials. Here, effects of CaTiO3 on phase structure, piezoelectricity and temperature stability of (1 – x)[0.95(K0.5Na0.5)NbO3–0.05(Bi0.5Na0.5)ZrO3]–xCaTiO3–0.2%MnO2 ceramics were studied. It was found that the orthorhombic-tetragonal phase transition temperature can be gradually decreased by increasing CaTiO3 content. Particularly, the improved strain temperature stability (strain varied < 15% when measurement temperature reaches 110 °C) and enhanced electrical properties (d33 ~ 296 pC/N and strain ~ 0.14%) can be observed in the ceramics with x = 0.02. Therefore, shifting the TO?T below room temperature is an effective way to promote temperature stability and electrical properties of KNN-based piezoelectric materials.
关键词： Lead-free piezoelectric ceramics,Temperature stability,CaTiO3,Piezoelectricity,KNN-based
更新于2025-09-10 09:29:36
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Improvement of electromechanical coupling coefficient in shear-mode of piezoelectric ceramics
摘要： Shear vibration mode of piezoelectric ceramic has been widely used in energy harvesting for its high electromechanical coupling coefficient (k15) and high piezoelectric constant (d15). In this study, the effects of dimensions on the piezoelectric shear performance of PZT-5A type ceramic were initially studied with ATILA/GiD finite element simulation to improve k15, and verified by experiments. We found out k15 dominantly correlates with the ratio of width to thickness, and dimension optimization was conducted for the first and high order shear vibrations. As a result, a maximum electromechanical coupling coefficient for k15 shear-mode reaching 0.612 was obtained in the first order harmonics. It is worth to note that the dimension ratio for optimized electromechanical coupling factor were in a similar scale regardless of the order of harmonics. In addition to the dimension optimization, the effect of mode coupling between shear vibration mode and unwanted mode was also investigated. The coupling between two vibrations did not only affect electromechanical coupling coefficient but also distorted resonance peak spectrum. Thus, the dimension ratios to avoid mode coupling was provided as the length should far away from the thickness. Finally, the effects of dimensions on mechanical quality factor were examined and the results were discussed. The mechanical quality factor will decrease when the mode coupling happens.
关键词： Electromechanical coupling coefficient,k15 shear-mode,Finite element analysis,Piezoelectric ceramics
更新于2025-09-10 09:29:36