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1.
Through modification of the heat-treatment process using a higher heating rate and a lower binder burnout temperature, the piezoelectric performance of water-quenched 0.67Bi1.05FeO3-0.33BaTiO3 (BF33BT) lead-free piezoelectric ceramics was improved. The observed physical properties of BF33BT ceramics were very sensitive to the process temperatures. The sintering temperature (TS) was changed within a narrow temperature range, and its effects were investigated. The largest rhombohedral distortion (90°-αR = 0.14°) and tetragonality (cT/aT = 1.022) were observed for the ceramic sintered at 980°C, and its Curie temperature was 476°C. This ceramic showed good piezoelectric properties and large grains; the piezoelectric sensor charge coefficient (d33) was 352 pC/N, and the piezoelectric actuator charge coefficient () was 270 pm/V. The high piezoelectric performance and low TS of BF33BT ceramics indicate their potential as new low-cost eco-friendly lead-free piezoceramics.  相似文献   

2.
High-temperature and high-performance piezoelectric ceramics were urgently required in the oil drilling, automotive and aerospace industries. Here, a solid solution of (0.67-x)BiFeO3-0.33PbTiO3-xBaTiO3 (BF-PT-BT) with dominant tetragonal phase was fabricated by a solid-state reaction method. The tetragonal distortion of BF-PT-BT ceramics from 1.152 to 1.050 is adjusted by changing the BT content. It is found that the c/a ratio has significant influence on the Curie temperature and electric properties. With the decrease of the tetragonal distortion, the coercive field and Curie temperature decrease, while both the dielectric and piezoelectric properties are enhanced significantly. When the c/a ratio range from 1.118 to 1.050, the piezoelectric coefficient d33 and the Curie temperature both depends linearly on the c/a ratio by relations of 106+(12.6/0.01)*(variation of c/a ratio) pC/N, and 600-(15.5/0.01)*(variation of c/a ratio) °C, respectively. The high Cuire temperature (>495 °C) and large piezoelectric coefficient (>106 pC/N) may have great potential for piezoelectric applications.  相似文献   

3.
The high-temperature and high-performance piezoelectric ceramics are required urgently in the petrochemical, automotive, and aerospace industries. In this work, the (0.85-x)BiFeO3-xPbTiO3-0.15BaTiO3 (BF-PT-BT, x = 0.21, 0.22, 0.23, 0.24 and 0.25) piezoelectric ceramics with both high Curie temperature and large piezoelectric constant d33 were presented. X-ray diffraction analysis shows that BF-PT-BT ceramics exhibit dominant perovskite structure with the coexistence of tetragonal (T) and rhombohedral (R) phases. The c/a ratio, Curie temperature, piezoelectric constant, dielectric constant and loss of the BF-PT-BT ceramics for x = 0.23 are 1.06, 546 °C, 222 pC/N, 545 and 0.013, respectively. Room temperature piezoelectric constant of BF-PT-BT ceramics is much higher than those of PbTiO3, PbNb2O6 and other ABO3 perovskite compounds (BaZrO3, Bi(Zn, Ti)O3, PbZrO3 and Pb(Mg, Nb)O3) modified ternary BiFeO3-PbTiO3 ceramics with similar Curie temperatures. The piezoelectric constant is almost unchanged after BF-PT-BT ceramics was annealed at 450 °C for 30 min, which is due to the stable switched non-180° domain and transformed R phase by annealing treatment.  相似文献   

4.
《Ceramics International》2020,46(5):6212-6216
0.02Pb(Sb1/2Nb1/2)O3-0.98Pb1-xBax(Zr0.53Ti0.47)O3 (PSN-PBxZT) ceramics with high Curie temperature and high piezoelectric properties were prepared by traditional solid state reaction measurement to meet the requirements for high temperature applications, and the crystal structure, dielectric, piezoelectric and ferroelectric properties were investigated. All the samples show a tetragonal crystal structure at room temperature and there was no noticeable change with the increasing of Ba2+ content. Doping of Ba2+ markedly improved piezoelectric properties of PSN-PZT, the maximum d33~560 pC/N, Tc ~317 °C at x = 0.05. Their outstanding piezoelectric properties will drive the development of high temperature industrial applications.  相似文献   

5.
Na0.5Bi4.5-xCexTi4O15 (x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) lead-free piezoelectric ceramics with high Curie temperatures are fabricated using the conventional solid-phase method. The effects of the Ce content on the phase structures, morphologies, and electrical properties of the Na0.5Bi4.5-xCexTi4O15 ceramics are systematically investigated. The appropriate content of Ce increases b/a and c/a and induces the distortion of the crystal structure. The increased b/a leads to a transverse asymmetry of the Na0.5Bi4.5-xCexTi4O15 ceramics, which facilitates the dipole flipping, thus enhancing the piezoelectric properties (d33 = 20 pC/N). Although the improved c/a increases the degree of tetragonality of the Na0.5Bi4.5-xCexTi4O15 ceramic, which decreases the Curie temperature (TC), the TC values of all samples are higher than 600°C, considerably higher than the practical application temperature. The Ce doping significantly reduces the dielectric loss of the sample and increases its dielectric performance. The improvements in electric properties by the cerium doping can expand its use in high-temperature environments for oilfield logging, aerospace, and military applications.  相似文献   

6.
The structure and properties of Mn-doped 0.67BiFeO3-0.33BaTiO3 ceramics are systematically investigated with respect to the effects of annealing prior to rapid cooling by quenching in air. Air-quenching induces a change in crystal structure from pseudo-cubic to rhombohedral, with higher quenching temperatures leading to an increased rhombohedral distortion. These structural changes are correlated with the appearance of more well-defined ferroelectric domain configurations. It is shown that the surface preparation procedures for XRD measurements can induce significant changes in the peak profiles, indicating differences in crystal structure between the surface and bulk regions. Frequency dispersion in the temperature-dependent relative permittivity for the as-sintered sample is significantly reduced after quenching, accompanied by enhancement of the Curie point and improved temperature-stability of piezoelectric properties. It is proposed that the formation of defect clusters by A-site cation diffusion during cooling is circumvented by quenching, leading to the observed modification of structural distortion and ferroelectric properties.  相似文献   

7.
《Ceramics International》2023,49(16):26391-26396
Obtaining both high Curie temperature and large piezoelectric constant simultaneously is of great significance for the application of actuators and sensors. In this research, the piezoelectric ceramics of (0.9-x)BiFeO3-xPbTiO3-0.1Ba(Zr0.5Ti0.5)O3 (BF-xPT-0.1BZT, x = 0.29, 0.30, 0.31 and 0.32) were fabricated by the traditional solid-state reaction method. BF-xPT-0.1BZT ceramics exhibit the tetragonal perovskite structure without detectable second phases, and the tetragonality c/a ratio and the tolerance factor of ceramics are about 1.03 and 0.98, respectively. SEM images reveal that ceramics are well densified with the average grain size of 5–12 μm. The Curie temperature TC of BF-xPT-0.1BZT ceramics is about 490–509 °C, slightly changing with the variation of PT content. The excellent comprehensive dielectric and piezoelectric properties are achieved for BF-0.31PT-0.1BZT ceramics with dielectric constant εr (1 kHz), tanδ, piezoelectric constant d33 and TC of 1001, 0.008, 230 pC/N and 509 °C, respectively. The significant enhancement of piezoelectric constant in the x = 0.31 sample is attributed to the enlargement of grain size. Moreover, the d33 and the planar coupling coefficient kp remain stable in the elevated temperature range of 200–400 °C, and the fluctuations are only 2% /℃ and 0.007% /℃, respectively, both of which are superior to that of BS-PT based piezoelectric ceramics. Our results indicate that BF-0.31PT-0.1BZT ceramics with high TC, large d33 and good thermal stability possess great potential for high temperature piezoelectric applications.  相似文献   

8.
Na0.5Bi0.5TiO3-BaTiO3 (NBT-BT)-based lead-free piezoelectric ceramics have been actively studied in recent years as a potential replacement for lead-based materials in ultrasonic applications. However, its relatively low thermal depolarization temperature (Td) is still an imperative obstacle hindering implementation in practical application. Recently, it was reported that quenching is an effective way to improve Td of NBT-based ceramics, but the essential mechanism is still unclear. In this study, 0.94Na0.5Bi0.5TiO3-0.06BaTiO3 (NBT-6BT) ceramics were quenched in air and liquid nitrogen, and then annealed in oxygen and nitrogen atmospheres to explore the origin of enhanced depolarization temperature. The results from this study correlate the enhancement of Td to the residual stress, which induces a stable rhombohedral ferroelectric phase, thereby increasing the thermal depolarization temperature of NBT-6BT. Our results indicate that the residual stress is also an important factor influencing the electrical properties of quenched piezoelectric ceramics, which should be given more attention in future studies.  相似文献   

9.
《Ceramics International》2022,48(7):9297-9303
Some lead-free piezoelectrics cannot meet the requirement for application in extremely harsh high-temperature surroundings. In this work, an enhanced piezoelectric performance with high piezoelectric coefficient (d33) and high Curie temperature (Tc) has been achieved by replacing the Ti4+ with the Co3+ in Na0.5Bi4.46Ce0.04Ti4-xCoxOy ceramics. The introduction of Co3+ decreases the B–O bond lengths, leading to the shrinkage of BO6 octahedra and lattice volume. The electron localization degree of B–O bond and the polarity of the BO6 octahedra were improved by diminution of lattice volume concomitantly, which were indicated by the first principle calculations. Therefore, an enhanced piezoelectric coefficient of 22 pC/N and high Tc of 690.2 °C have been realized in Na0.5Bi4.46Ce0.04Ti4-xCoxOy ceramics with x = 0.02 mol. Our work gives a good paradigm to design superhigh temperature piezoelectric devices for practical application in extremely harsh circumstances.  相似文献   

10.
(Bi1/2Na1/2)TiO3-based materials have received much attention due to large electro-strain and high piezoelectric constant (d33), but the tough issue is that the existence of inherent depolarization temperature (Td) limits the temperature stability and application temperature range. Previously, reports about the formation of BNT/oxide (i.e., ZnO, Al2O3) composites thought that Td can be deferred to a higher temperature and then thermal depolarization improves. However, the deferred Td of BNT/oxide composites is limited, accompanied by a low d33. Here, we design the {[Bi0.5(Na0.8K0.2)0.5]1-xPbx}TiO3 ceramics, leading to a big shift of Td from 77 ℃ to 390 ℃. Large d33 (140 pC/N) and high Td (∼263 ℃) can be simultaneously achieved for the sample with Pb=0.05, and Td could be further deferred higher (390 ℃) for Pb=0.20. The off-centre displacement of Pb induced by Pb-O hybridization in the PbO12 polyhedron and ferroelectric order stabilized by the addition of Pb can provide the driving force to strengthen the ferroelectric order, and then promote the thermal stability.  相似文献   

11.
Herein, nano-BaTiO3/Bi2O3/Fe2O3 and BaCO3/TiO2/Bi2O3/Fe2O3 were respectively used to prepare 0.7BiFeO3-0.3BaTiO3 (0.7BF-0.3BT) ceramics by conventional solid-state method and clarify the reaction path, phase structure, microstructure, ferroelectric, and piezoelectric properties. 0.7BF-0.3BT ceramic using nano-BaTiO3 with cubic phase (CBT) undergoes the formation of rhombohedral α-phase (Rα) and the transition from Rα and CBT to rhombohedral β-phase (Rβ) and pseudo-cubic (PC) phases, while the counterpart using BaCO3/TiO2 directly generates Rβ and PC. Nano-BaTiO3 can decrease pores and oxygen vacancies in the resultant ceramics comparing to BaCO3/TiO2, which is due to an inhibited decomposition of Rα and a weaker reduction of Fe3+ to Fe2+, leading to increased density and reduced leakage current density. Benefitting from a proper phase ratio, increased density and reduced leakage current density, the enhanced piezoelectric properties d33?=?210?pC/N, kp?=?0.34, Pr?=?31.2?μC/cm2 and TC?=?514?°C are obtained in 0.7BF-0.3BT ceramic using nano-BaTiO3. Our work reveals the importance of raw materials and the potential of BF-BT as a high-temperature lead-free piezoelectric ceramic material.  相似文献   

12.
《Ceramics International》2023,49(20):32510-32520
Eco-friendly lead-free energy-storage ceramics featuring high energy storage properties and ultra-high stability have been regarded to be one of the most potential materials in the field of energy storage. In this work, a new element system, (1-x)(0.6Bi0.5Na0.5TiO3-0.4SrTiO3)-xBi[Zn2/3(Nb0.5Ta0.5)1/3]O3 ((1-x)BNST-xBZNT) lead-free ceramics, were synthesized via a conventional solid-state sintering technology. And the phase structure, microstructure and energy storage properties of the (1-x)BNST-xBZNT ceramics were comprehensively studied. After the introduction of BZNT, the average grain size of the materials is greatly decreased, thereby enhancing the dielectric breakdown strength (DBS). Additionally, the thermal stability of the ceramics is significantly improved via regulating the doping content and sintering temperature. Furthermore, the ferroelectric long-range order of the ceramics is decomposed into randomly-oriented polar nano-domains (PNRs) after introducing BZNT, leading to strong relaxor behavior and significantly reducing remanent polarization (Pr). As a result, even under a relatively low electric field of 139 kV/cm, the 0.98BNST-0.02BZNT ceramic sintered at 1150 °C possesses high values of energy storage efficiency (η) value of 92.78% and total energy storage density (Wtot) of 1.67 J/cm3 as well as remarkable thermal stability (25–175 °C), frequency stability (20–70 Hz) and fatigue resistant stability (100-105 cycles). This investigation provides a useful reference for developing advanced energy storage ceramics by regulating the doping content and sintering temperature.  相似文献   

13.
《Ceramics International》2022,48(24):36478-36489
Recently, BaTiO3-BiMeO3 ceramics have garnered focused research attention due to their outstanding performance, such as thermal stability, energy efficiency and rapid charge-discharge behavior, however, a lower recoverable energy storage density (Wrec) caused by a relatively low Pmax (<30 μC/cm2) mainly hinders practical applications. Herein, the energy density and thermal stability are improved by adding a tertiary component, i.e., Bi0.5Na0.5TiO3, into BaTiO3-BiMeO3, resulting in xBi0.5Na0.5TiO3-modified 0.88BaTiO3-0.12Bi(Zn2/3Nb1/3)O3 ceramics, with x = 0, 0.1, 0.2, 0.3 and 0.4, with superior dielectric properties and eco-friendly impact. Incorporating Bi0.5Na0.5TiO3 with a high saturation polarization and Curie temperature not only significantly enhances Pmax of BaTiO3-Bi(Zn2/3Nb1/3)O3 but also improves Curie temperature of (1-x)[0.88BaTiO3-0.12Bi(Zn2/3Nb1/3)O3]-xBi0.5Na0.5TiO3 system. Combined with complementary advantages, modified ceramics render a superior energy storage performance (ESP) with a high Wrec of 3.82 J/cm3, efficiency η of 94.4% and prominent temperature tolerance of 25–200 °C at x = 0.3. Moreover, this ceramic exhibit excellent pulse performance, realizing discharge energy storage density Wdis of 2.31 J/cm3 and t0.9 of 244 ns. Overall, the proposed strategy effectively improved comprehensive properties of BaTiO3-based ceramics, showing promise in next-generation pulse applications.  相似文献   

14.
Effect of Zn site-selected doping on electrical properties, high-temperature stability and sensitivity of piezoelectric response for BiFeO3-BaTiO3 ceramics was investigated. The results revealed that the addition of Zn leaded to an evident modification of the microstructure. The B-site selected doping was a more effective approach in improving piezoelectric properties as well as their thermal stability than those of A-site selected doping. Moreover, the enhanced piezoelectric properties accompanying by excellent high-temperature stability and sensitivity in B-site selected doping ceramics were obtained. The microstructure, domain switching behavior and temperature-dependent piezoelectric response in Zn site-selected doping ceramics were investigated, and their relationships with improving piezoelectric properties and high-temperature stability were explored. These results showed that the B-site selected doping ceramics had excellent piezoelectric properties (d33 = 192pC/N) along with a high-temperature stability (Td = 450 °C).  相似文献   

15.
In this work, the crystalline phase, domain structure, and electrical properties of [Bi0.5(Na0.84K0.16)0.5]0.96Sr0.04Ti1-xNbxO3 (x = 0.010–0.030) ceramics are investigated. Increasing the Nb content induces the phase transition from coexistent rhombohedral and tetragonal phases to a single pseudo-cubic phase, and the lamellar ferroelectric domains evolve into polar nanoregions. Decreased ferroelectric-to-relaxor transition temperature and enhanced frequency dispersion are found in the temperature-dependent dielectric constant and loss, implying a transition from the non-ergodic to ergodic relaxor state. The Nb substitution significantly degrades the long-range ferroelectric order with sharply decreased piezoelectric coefficients from ? 140 to ? 1 pC/N. However, a large strain of 0.32% at 5 kV/mm (normalized strain of 640 pm/V) is obtained around the critical composition of x = 0.0225. The composition of x = 0.030 shows good temperature insensitivity of the strain response, characterized by 308 pm/V with less than 15% reduction from 25 °C to 125 °C.  相似文献   

16.
Lead-free metamaterials with enormous effective apparent piezoelectric response has been fabricated by applying an asymmetric chemical reduction to Na0.5Bi0.5TiO3 (NBT)-based ceramics. To achieve high performance, optimization of the reduction conditions is required. In this study, we analyzed the effect of reduction temperature and time on the reduction thickness of NBT-based ceramics. We found that the reduction reaction between NBT-based ceramics and graphite is an interface reaction rate-controlled process. The reduction thickness has a linear relationship with the reaction time at a fixed reduction temperature. The lower activation energy of NBT-based ceramics than that of lead-based materials indicates the lead-free ceramics are easier to be reduced. The effect of the reduction on the flexoelectric-like response was further explored, and the maximum response (?>1 mC/m) was measured in the ceramics having a reduction-thickness-to-total-thickness ratio of around 0.28. This study provides a guideline to optimize the fabrication conditions of the NBT-based metamaterials.  相似文献   

17.
In this work, Na0.5Bi4.5Ti3.94–xMn0.06NbxO15+y bismuth-layered ferroelectric ceramics were prepared by a solid-state reaction method. The effect of Nb5+ content on crystal morphology, electrical properties, and piezoelectric performance were systematically investigated. The results show that the introduction of Nb5+ into Na0.5Bi4.5Ti3.94–xMn0.06NbxO15+y ceramics to replace Ti4+ increases the ratio of b/a lattice parameter, leading to the TiO6 octahedral distortion and the structural transformation tendency from the orthorhombic to tetragonal phase, which facilitates dipole movements of Na0.5Bi4.5Ti3.94–xMn0.06NbxO15+y ceramics. Therefore, the ferroelectric properties of Na0.5Bi4.5Ti3.94–xMn0.06NbxO15+y ceramics are improved, and an enhanced piezoelectric coefficient of 30 pC/N combining great temperature stability with d33 value higher than 25 pC/N in the temperature range of 25°C–450°C has been realized in Na0.5Bi4.5Ti3.94–xMn0.06NbxO15+y ceramics with x = 0.08 mol. Our work provides a good model for designing lead-free ultrahigh Curie temperature piezoelectric devices that can be practically applied in extremely harsh environments.  相似文献   

18.
0.7BiFeO3-0.3BaTiO3 (BFO-0.3BT) ceramics were prepared to uncover the impacts of sintering temperature (TS) and dwell time (td) on the microstructure and electrical properties. With increasing the TS or td, the grain sizes increase along with the porosity decreases, which is in favor of the alignment of dipole. However, excess TS or td are inclined to cause the volatilization of Bi2O3, which deteriorates piezoelectric properties. Because of the R-T two-phase coexistence, low defect ions concentration and porosity, as well as appropriate grain size, the excellent d33?=?208?pC/N and kp?=?35.46% as well as Pr?=?28.52?μC/cm2 were achieved in BFO-0.3BT ceramics at TS?=?1000?°C and td?=?6?h. In addition,large unipolar strain 0.13% and d33*?=?256.2?pm/V also were obtained in BFO-0.3BT ceramics at TS?=?1000?°C and td?=?6?h. This research indicates that the porosity and defect ion concentration as well as grain size also play an important role in piezoelectric properties in BFO-BT ceramics.  相似文献   

19.
The structural and dielectric properties of Na0.5Bi0.5TiO3 (NBT) ceramics and crystals have been investigated and are compared to that of Pb(Zr0.55Ti0.45)O3 (PZT55/45) and Pb(Mg1/3Nb2/3)0.72Ti0.28O3 (PMNT 72/28) ceramics. X-ray diffraction (XRD) profiles for (100), (110), (111), (200), (220), and (222) (referred to cubic structure) reveal that the monoclinic structure with Cc space group exists both in the NBT single crystal and ceramics. The diffraction profile obtained with high resolution laboratory XRD for the NBT single crystal can be well described, using Cc model instead of R3c model. The dielectric constant of NBT below Thump shows some similarity to that of PZT45/55 ceramics below 50°C in which oxygen octahedron rotations cause the frequency dispersion of the dielectric constant. The temperature-dependent dielectric constant for NBT can be deconvolved into two independent processes. The lower temperature process shows a typical relaxor characteristic and follows the Vogel-Fulcher relationship. The other process at higher temperature shows less frequency-dependent behavior. Comparing the dielectric constant of NBT with that of PZT55/45 and PMNT72/28 reveals that both oxygen octahedral rotations and random electric fields play an important role in the frequency dispersion of the dielectric constant for NBT relaxor feroelectric.  相似文献   

20.
The validity of Mn element on 0.93(Bi0.5Na0.5)TiO3‐0.07Ba(Ti0.945Zr0.055)O3 ceramics (BNT‐BZT‐xMn) is certified by doping. On account of multiple effects introduced by Mn, the appropriate Mn content facilitates property improvement effectively. Compared with pure BNT‐BZT, d33 of the component x = 0.25 increases about 8% up to 187 pC/N and Qm of the component x = 1 increases about 84% up to 197. Thermally stimulated depolarization currents (TSDC) measurement reveals Mn additive is helpful to pyroelectric properties as well. The Mn‐doped component x = 0.125 exhibits better pyroelectric performance at room temperature. Corresponding pyroelectric coefficient and the figures of merit reach up to 0.061 μC/(cm2 °C), Fi=217 pm/V, Fν = 0.023 m2/C, and Fd = 12.6 μPa?1/2, respectively, even superior to lead‐based ceramics. Similar pyroelectric advantage is also observed in the component x = 0.5 near depolarization temperature Td. Mn doping has slight harmful influence on the ferroelectric‐to‐relaxor transition temperature TF?R, as well as Td, but hardly shows restriction on application. These results confirm Mn doping is an available strategy to improve BNT‐based ceramics. Therefore, Mn‐doped BNT‐BZT ceramics will be excellent candidates in area of high‐power piezoelectric application and pyroelectric detectors.  相似文献   

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