Lead Zirconate Titanate Ceramics Research Articles

Achieving large strain and low hysteresis in BiFeO3-BaTiO3-based piezoelectric ceramics

The high strain hysteresis has impeded lead-free piezoelectric ceramics to replace lead zirconate titanate ceramics applied in actuators. In this study, we report a significant advancement with the synthesis of a novel BiFeO3-BaTiO3-(Ba0.6Sr0.4)TiO3 (BF-BT-BST) system. The optimal composition has demonstrated a remarkable strain of 0.42 % coupled with a notably low hysteresis of 21 %. It is found that the incorporation of BST into BF-BT facilitates the transition from the rhombohedral phase to the pseudo-cubic phase, which in turn significantly enhances the relaxor ferroelectric characteristics of the ceramic. Through adjusting the composition proportion of BST, a unique ferroelectric domain structure is established for the BF-BT-0.04BST ceramic, where polar nanoregions (PNRs) are surrounded by ferroelectric macrodomains. The domain structure enables the ceramic to have the ability to respond the external electric field quickly compared to the PNRs for typical relaxor composition, thereby leading to large strain and low hysteresis simultaneously. Hence, it is inferred that the ferroelectric macrodomains simplify the response process of the PNRs under electric field. This study provides an efficient strategy to break through the bottleneck of large strain hysteresis for BF-BT ceramic, and gives a deep comprehension for the improvement of the strain characteristics.

Damage localization on reinforced concrete slab structure using electromechanical impedance technique and probability-weighted imaging algorithm

Damage localization plays a key role in structural damage identification and health monitoring. This paper proposed a new damage localization approach using electromechanical impedance/admittance (EMI/EMA) technique integrated with probability-weighted imaging algorithm based on Gaussian distribution. The proposed approach comprises five steps namely measurement of the EMA signature from an array of piezoelectric ceramic lead zirconate titanate (PZT) transducers, computation of statistic damage indicator, establishment of regression model for the indicator, damage visualization via Gaussian distribution and final damage localization. Experimental validation of the approach was conducted on a reinforced concrete (RC) slab with artificial crack damages detected by using an array of surface-bonded PZT patches. Comparative studies on localization accuracy were performed by utilizing root mean square deviation (RMSD), baseline-changeable RMSD namely RMSDk, mean absolute percentage deviation (MAPD) and correlation coefficient (CC). Experimental results demonstrated that the proposed approach could achieve precise localization of concrete crack with error as small as 0 mm, and that using RMSDk index exhibited the highest localization accuracy in average. The proposed approach promoted the capability of the EMI technique in characterization of concrete structural damages.

Flash sintering of lead zirconate titanate ceramics under high voltage at room temperature

Flash sintering has been applied to various ceramics since it was first reported. However, the flash sintering of lead zirconate titanate (PZT) at room temperature has not been accomplished. In this study, flash sintering of PZT piezoelectric ceramics at room temperature was realised for the first time. Subsequent to surface treatment in a low-pressure environment, the sample was flash-sintered at a high voltage in air. The sample became dense rapidly during sintering. The results showed that after 300 s of sintering, the flash-sintered samples had a high density (98.1%) and d33 values (273 pC/N). The d33 is the highest compared with flash sintering of PZT through the furnace temperature of several hundred degree Celsius. Owing to the extremely short sintering time and the absence of heating devices, this method can greatly reduce energy consumption and lead to volatilisation, providing a new method for the rapid preparation of piezoelectric ceramics.

Evaluation of Damage Severity and Strength of Structural Member Using Macro‐Molecular PZT Sensor

AbstractThe structural health of various engineering systems has been easily monitored using macromolecular piezoelectric ceramic lead zirconate titanate (PZT) based electromechanical impedance (EMI) technique. It is in need to study the evaluation of various levels of damage and the present strength of structural systems to enhance the life of structures. Once damages occur, due to continuing usage they usually propagate in certain directions. Moreover, the increase in the severity of damages may lead to failure of the structural components or even the whole structure. Interaction between structure and PZT, which is found effective in EMI technique, is to identify effective damage detection. The macro‐molecular PZT's self‐actuating and sensing properties are utilized by the electromechanical impedance (EMI) method. The higher modes of vibration are locally activated by the local application of an AC source on the PZT transducers attached to the host structure. In this paper, the EMI technique using surface‐bonded PZT transducers is employed to obtain the structural health signature. The experiment is carried out on a real‐size concrete frame structure subjected to artificial damage to identify and locate the damages using frequency variations, and the severity is checked using extracted equivalent parameters; the damage index. This method also can identify hair‐like cracks at an early stage, which explains how it can shield the building from serious failures.

Exploring the Mpemba effect: a universal ice pressing enables porous ceramics.

Piezoceramics with global porosity and local compaction are highly desired to exploit the combination of mechanical and electrical properties. However, achieving such a functional combination is challenging because of the lack of techniques for applying uniform pressure inside porous ceramic green parts. Nature provides many examples of generating strong forces inside the macro and micro channels via the state transformation of water. Inspired by these phenomena, we present a technique of "ice and fire", that is, water freezing (ice pressing) and high-temperature sintering (fire), to produce ideal porous piezoceramics. We introduce a new compaction method called the "ice pressing method", which manipulates liquid phase transition for compaction. This method has several advantages, including uniform pressure distribution, a wide pressure range, high effectiveness, and selective freezing. It can generate an ultrahigh pressure of up to 180 MPa on the piezoceramic green skeletons in minutes while retaining their functional pore structures. By exploiting the Mpemba phenomenon, we further accelerate the compaction procedure by 11%. The first ice-pressed and second fire-consolidated lead zirconate titanate (PZT) ceramics are highly densified and exhibit an outstanding piezoelectric response (d33 = 531 pC N-1), comparable to conventional pressed bulk counterparts and 10-20 times higher than those of unpressed materials. The novel ice pressing method breaks the limitation of lacking a compaction technique for porous ceramics. The versatile and effective ice pressing method is a green and low-cost route promoting applications in sensors, acoustics, water filtration, catalyst substrates, and energy harvesting.

Flash sintering of Lead Zirconate Titanate (PZT) with minimal lead oxide loss and enhanced dielectric properties

Generally, a high temperature (>1100°C) is required to sinter Lead Zirconate Titanate (PZT) ceramics. Such a high sintering temperature results in significant lead oxide evaporation which is a major environmental problem due to its toxicity. In this work, we have performed flash sintering of Lead zirconate Titanate (Pb (Zr0.5Ti0.5) O3)) using a novel setup and compared the phase and microstructural evolution, dielectric, piezoelectric properties and lead loss with conventionally sintered Lead zirconate Titanate (PZT). The lead oxide evaporation has been reduced by 5–10 times compared to conventionally sintered PZT. Results also show that the flash-sintered samples' dielectric constant is about ∼ six times higher than the conventionally sintered samples with similar dielectric loss. Ferroelectric and piezoelectric properties of flash sintered PZT on the other hand are lower than conventionally sintered PZT. The mechanisms behind the anomalous properties are discussed using structural and microstructural observations.

Influence of polyethylene content on preparation and properties of lead zirconate titanate piezoelectric ceramics via vat photopolymerization

Vat photopolymerization has garnered significant research interest due to its capabilities in achieving complicated designed structures and high resolution. However, there are still significant technical difficulties in manufacturing some piezoceramic parts because of the high refractive index and ultraviolet light absorptivity of these ceramic powders. Herein, we overcome this challenge for lead zirconate titanate (PZT) ceramics by introducing polyethylene (PE) additions with ultralow refractive index and UV light absorptivity into PZT slurries. As the PE content increases, the curing depth shows a clear upward trend. When the PE content is 30 vol%, the curing depth of PZT slurry could ensure the adequate interlayer combination. Besides, PZT ceramics with different volumes of porosity could be obtained by modulating PE content. The relative density of sintered PZT ceramics decreased from 83.12 % to 68.06 %. Furthermore, the samples with 30 vol% PE exhibited satisfactory dielectric and piezoelectric properties (ϵr =1911, tanδ=0.027, d33 = 308 pC/N, g33 = 1.82 × 10−2 Vm/N and d33g33= 5.61 × 10−12 m2/N). These results indicate that the addition of PE additives is an effective and universal approach to improve the curing depth of ceramic slurries and expand the range of processable materials for vat photopolymerization technologies.

Deep learning of electromechanical admittance data augmented by generative adversarial networks for flexural performance evaluation of RC beam structure

Deep learning networks facilitate automated damage identification and performance evaluation for concrete structures using electromechanical impedance/admittance (EMI/EMA) technique, while data quantity and quality limit the performance of such a data-driven network. For the first time, this paper proposed a data-augmentation approach using deep-convolutional admittance generative adversarial networks (AdmiGAN) to solve data deficiency and measurement inefficiency for deep learning-based flexural performance evaluation of reinforced concrete (RC) structures. In the approach, a new data normalization procedure was developed to collaboratively foster AdmiGAN-based EMA data synthesis, and synthetic datasets were fed into an adaptive convolutional neural network (CNN) for deep learning. Proof-of-concept experiment was conducted on a four-point bending RC beam structure, which was continuously monitored from initial loading to final failure by three surface-bonded piezoelectric ceramic lead zirconate titanate (PZT) patches. Qualitative detection of stress and damage was performed by traditional feature analysis of EMA signatures, automated performance evaluation was attempted by using CNN approach. Results demonstrated that the AdmiGAN required merely 5 groups of EMA signatures to generate high-accuracy dataset with 174 times of speed faster than conventional measurement method, and the AdmiGAN cooperated with CNN provided a new paradigm of data-driven structural performance evaluation with high accuracy, efficiency, and intelligence.

Effect of the polystyrene particle size on dielectric and piezoelectric properties of PZT piezoelectric ceramics via vat photopolymerization (VPP)

The fabrication of lead zirconate titanate (PZT) ceramics using VPP technology presents a significant challenge due to the suboptimal curing performance and printability of PZT ceramic slurry. In this study, we successfully manufactured PZT ceramics utilizing vat photopolymerization (VPP) technology by incorporating polystyrene (PS) powders of varying particle sizes into the PZT ceramic slurries. Our investigation revealed that the incorporation of PS powders dramatically enhances the curing performance of the PZT slurry. Furthermore, it was found that the electrical properties of resultant ceramics are intrinsically linked to the morphology and dimensions of the induced pores. However, our research findings indicate that an excessive particle size of PS can negatively impact the dielectric and piezoelectric properties of the PZT ceramics, underscoring the need for careful control over PS powder size during fabrication. The pronounced discrepancy in particle size between PZT and PS powders may lead to suboptimal interlayer combination within specific regions of the green body. Consequently, this could render the PZT ceramics susceptible to additional defect formation. Nonetheless, the fabricated PZT piezoelectric ceramics with a PS particle size of 3 µm demonstrate exceptional electrical characteristics. This research proposes a straightforward and productive approach for broadening the spectrum of processable ceramics within the domain of VPP technology, while offering a comprehensive understanding of the influence exerted by the morphology and dimension of pores on dielectric and piezoelectric properties of ceramic materials.

Modeling polarization switching response of ferroelectric ceramics based on multiple natural configuration theory

Ferroelectric ceramics experience polarization switching, which is macroscopically shown by nonlinear hysteretic responses when subjected to high compressive stresses and/or high amplitude of the electric field. We model the nonlinear hysteretic response of ferroelectric ceramics by considering evolutions of microstructural changes associated with changes in the dipole orientations due to both electrical and mechanical stimuli. We adopt the theory of multiple natural configurations, associated with multiple stress-free and electric-field-free states, in incorporating the effect of microstructural changes on describing the nonlinear electro-mechanical hysteretic response of ferroelectric ceramics. The first stress-free and electric-field-free states are associated with the original microstructure of the materials, in which the dipoles in the ferroelectric ceramics are randomly oriented. The new configurations are formed when the ferroelectric ceramics are subjected to relatively large stimuli, which align the dipole orientations. As each configuration is associated with a specific microstructure (a state of dipole orientations), mechanical and electrical properties characterized at different configurations will be different. To examine the model, experimental data on PZT (lead zirconate titanate) ceramics under electric and stress fields, available in the literature, are used. The model is capable of describing the hysteretic response in PZT under electro-mechanical stimuli.

Three-dimensional piezoceramic sheets via mold-assisted sintering as 3D energy transducers

Bulk piezoceramics are widely used and functional materials, but they are hard to be shaped to adapt to complex 3D surfaces. Most existing ceramic shaping techniques, like 3D printing, come at the cost of physical properties such as piezoelectricity and thermal stability. Here to fabricate 3D piezoceramic sheets, we report a mold-assisted sintering (MAS) method that can replicate 3D surfaces with nonzero Gaussian curvatures while maintaining the intrinsic properties. Assisted with supporting molds, the MAS exploits elastic-to-viscous transition of piezoceramic powder compacts during sintering, bypassing the boundaries of deformation and surface development in an elastic continuum. We successfully replicate shapes to sintered lead zirconate titanate (PZT) ceramics from designed molds with saddle, sine and spherical surfaces, respectively. The PZT ceramic replicas show high piezoelectricity and excellent conformability towards nonplanar surfaces (maximum deviation 90 μm). We further demonstrate the advantage of the conformal curved piezoceramics by using them for wirelessly transferring power over a pipeline. The MAS method is low-cost, simple, scalable and applicable to various 3D energy transducers.

Grain size effect on piezoelectric properties of rhombohedral lead zirconate titanate ceramics

Lead zirconate titanate (PZT)-based piezoelectric ceramics are important functional materials for various electromechanical applications due to their excellent performance and temperature stability. Herein, the rhombohedral PbZr0.55Ti0.45O3 ceramics with increasing average grain size from 3.57 μm to 10.85 μm were prepared by a conventional solid-state reaction method. The grain-size dependent dielectric, ferroelectric and piezoelectric properties were systematically investigated. With the increasing grain size, a significant softening effect with enhanced electromechanical properties was observed. Results of piezoresponse force microscopy show that the formation of non-180° domain walls was strongly repressed in the fine-grain samples, resulting in decreased domain wall mobility. Meanwhile, a noteworthy hardening effect was also observed in the coarse-grain samples with high domain wall mobility, which may be related to the enhanced bulk effect with increasing grain size. The results of this work confirmed that grain size engineering is an effective strategy for designing piezoelectric materials with excellent combination properties.

Deep learning-based denoising of acoustic images generated with point contact method

Abstract The versatile nature of ultrasound imaging finds applications in various fields. A point contact excitation and detection method is generally used for visualizing the acoustic waves in Lead Zirconate Titanate (PZT) ceramics. Such an excitation method with a delta pulse generates a broadband frequency spectrum and wide directional wave vector. The presence of noise in the ultrasonic signals severely degrades the resolution and image quality. Deep learning-based signal and image denoising has been demonstrated recently. This paper bench-marked and compared several state-of-the-art deep learning image denoising methods with the classical denoising methods. The best-performing deep learning models are observed to be performing at par or, in some cases, even better than the classical methods on ultrasonic images. We further demonstrate the effectiveness and versatility of the deep learning-based denoising model for the unexplored domain of ultrasound/ultrasonic data. We conclude with a discussion on selecting the best method for denoising ultrasonic images. The impact of this work may help ultrasound-based defects identification equipment manufacturers to adopt a deep learning-based denoising model for more wider and versatile use.

High piezoelectricity performance in PSBZT ceramic for ultrasonic transducer

Lead zirconate titanate (PZT) ceramics possess great potential for practical applications and thus improving their piezoelectric properties is crucial. [Formula: see text][Formula: see text][Formula: see text][Formula: see text][Formula: see text][Formula: see text]O3 (PSBZT) ceramics with high Curie temperature and excellent piezoelectric properties were fabricated via a conventional solid-state method, and the effect of Ba[Formula: see text] doping on the structural, dielectric, piezoelectric and ferroelectric properties was studied in detail. It is shown that doping of Ba[Formula: see text] significantly enhanced the piezoelectric properties of PSZT, the maximum [Formula: see text]533 pC/N and [Formula: see text]361[Formula: see text]C at [Formula: see text]= 0.02 were acquired. Furthermore, PSZT and PSBZT ceramics were used to prepare single element ultrasonic transducers, and their performance were compared and evaluated. The results demonstrate that the PSBZT ceramic-based transducer possesses better sensitivity and bandwidth than the PSZT ceramic-based transducer.

Poling lead zirconate titanate ceramics with the assistance of stress

Poling lead zirconate titanate ceramics with the assistance of stress

Lead zirconate titanate ceramics with aligned crystallite grains.

The piezoelectric properties of lead zirconate titanate [Pb(Zr,Ti)O3 or PZT] ceramics could be enhanced by fabricating textured ceramics that would align the crystal grains along specific orientations. We present a seed-passivated texturing process to fabricate textured PZT ceramics by using newly developed Ba(Zr,Ti)O3 microplatelet templates. This process not only ensures the template-induced grain growth in titanium-rich PZT layers but also facilitates desired composition through interlayer diffusion of zirconium and titanium. We successfully prepared textured PZT ceramics with outstanding properties, including Curie temperatures of 360°C, piezoelectric coefficients d33 of 760 picocoulombs per newton and g33 of 100 millivolt meters per newton, and electromechanical couplings k33 of 0.85. This study addresses the challenge of fabricating textured rhombohedral PZT ceramics by suppressing the otherwise severe chemical reaction between PZT powder and titanate templates.

Exploring ferroelectric properties of sol-gel lead zirconate titanate nano-crystalline thin films and ceramics by doping ytterbium for energy-storage application

This work concerns how ytterbium affects the ferroelectric characteristics of sol-gel Yb doped lead zirconate (PYZ) and lead zirconate titanate (PYZT) thin films and ceramics. Lead zirconate Pb(0.9) )-Yb0.01 Zr (0.09 (PYZ) and lead zirconate titanate Pb0.9-Yb0.01-Zr0.045-Ti0.045 (PYZT) doping with ytterbium thin films were prepared on a glass substrate using a sol-gel doctor blade coating technique at low temperature. The structure of the synthesized thin films and ceramic nanocrystals was examined using X-ray diffraction (XRD), transmission electron microscopy (TEM), and electron diffraction (ED). PYZ and PYZT ceramics had 11.8 nm and 30.65 nm respectively, whereas PYZ and PYZT thin films featured nanocrystals that were, respectively, 17.5 nm and 13.87 nm in size. Particle size was determined to be entirely consistent across the TEM and XRD data. Dielectric investigations showed that the dielectric constant was dropping for ceramic samples as compared to thin film samples. According to hysteresis loop estimates, the energy-storage density and efficiency for thin films and ceramics were average approximately 39.35 J cm−3 and 66.02 percent for (PYZ) and 71.33 J cm−3 and 70.91 percent for (PYZT), respectively. The results showed that the ferroelectric, dielectric, and structural properties of materials affected the ytterbium content. (PYZ) and (PYZT) thin films and ceramics may have a prospective use in energy storage devices.

Transient liquid phase bonding technique for ultrahigh-vacuum compatible bimorph mirrors used in soft x-ray beamlines.

Bimorph mirrors place stringent requirements on the welding technology of silicon substrates and piezoelectric ceramics to ensure their ultrahigh-vacuum compatibility. Conventional welding techniques usually require high temperature and pressure, which have a high impact on the welding substrate, while the use of organic adhesives for bonding does not guarantee their stability in ultrahigh vacuum. Here, the transient liquid phase bonding technology based on an Au-In metal system was studied to meet the requirement for ultrahigh-vacuum application. The microstructure, chemical composition, and related mechanical properties of the bonding at different welding conditions were investigated. Meanwhile, the piezo ceramics and the bond were baked at 150 °C to test the stability. The results show that a stable bonding was achieved between centimeter-scaled single crystal silicon and lead zirconate titanate ceramics at 200 °C temperature and 2.5 MPa pressure, and the piezo ceramics and the bond are not damaged by baking to 150 °C for 48 h.

Structural Phase Modulation in Lanthanum‐ and Tin‐Cosubstituted Pb(Zr,Ti)O3 Ceramics and its Energy and Pyroenergy Storage Properties

La‐ and Sn‐cosubstituted lead zirconate titanate () ceramics are synthesized using a solid‐state reaction route. These (PLZST) ceramics in pure form are found to exist in dual phase () and single phase (Cc) depending on the amount of La/Sn cosubstitution. PLZST ceramics exhibit thin P–E loops with enhanced polarization when measured at 393 K. Olsen cycle method is used to estimate the pyroenergy harvesting abilities of the samples under study. The estimated maximum energy storage density for PLZST () ceramics at 393 K is 1.16 J cm−3 [efficiency (η) > 96%]. The PLZST ceramics exhibit a remarkable hardness of 9.08 GPa. These results indicate that PLZST ceramics with excellent multifunctional properties are potential candidates in the field of electroceramic devices.

Hardening Effect in Lead-Free KNN-Based Piezoelectric Ceramics with CuO Doping.

As the most promising lead-free piezoelectric ceramics to replace lead zirconate titanate (PZT) ceramics, potassium sodium niobate (KNN) ceramics have been widely studied for their application prospects in various electronic devices. Increasing Qm while maintaining a high piezoelectric activity is quite important for piezoelectric ceramics applied in ultrasonic devices. A KNN-based ceramic with high d33 and Qm is prepared by a conventional solid-state technique to construct polycrystalline phase boundaries and induce defect dipoles. The best overall performance can reach d33 = 260 pC/N, Qm = 210, and TC = 293 °C. The temperature dependence of the relevant parameters is tested, where Qm increases but d33 decreases with the rise of temperature accompanied by escaping ferroelectric boundary, which shows that the polarization rotation plays an important role in the two parameters. The hardening effect of KNN-based ceramics with CuO doping is further studied by first-principles calculations, demonstrating that the Cu doping strongly disturbs the ferroelectric order, but the formation of defect dipoles could stabilize the ferroelectric order. It is illustrated that defect dipoles always find their ground state at the site near the domain walls and the oriented defect dipoles hinder the polarization rotation severely, confirming the role of the defect dipoles in KNN-based materials.