Commercial Lead Zirconate Titanate Research Articles

Energy harvesting and storage with ceramic piezoelectric transducers coupled with an ionic liquid-based supercapacitor

One of the main issues of wearable electronic devices regards their power supply and autonomy. The exploitation of mechanical energy from body motion and vibrations can be realized by using piezoelectric materials coupled with a proper energy storage device. To this aim, Self-Powered Supercapacitors (SPSCs) have been investigated over the last decades, either as internally integrated SPSC (iSPSC), where the piezoelectric element of the device is used as Super Capacitor (SC) separator, or via an external integration (eSPSC), where the piezoelectric unit and the SC are connected by a bridge rectifier. In this paper, an eSPSC power supply is developed by integrating a stuck of commercial ceramic piezoelectric disks and an ionic liquid-based micro-SC. In detail, a stack of 15 commercial lead zirconate titanate (PZT) disks is used as the energy harvesting unit and mechanically stressed by a compressive force of 85 N at 2 Hz. The piezoelectric output successfully charged the 22 mF supercapacitor up to 3.1 V after 2 h of test, achieving a stored energy value equal to 110 mJ. The proposed integrated system outperforms the state-of-the-art SPSC assembled with micro-SC (both iSPSC and eSPSC). The use of the two different units (piezo-energy harvesting unit and micro-SC energy storage unit) allows an independent sizing and tuning of the supercapacitor according to the output current of the piezoelectric unit.

Design, Modeling and Fabrication of a Novel Class V Flextensional Transducer: The Sea-Shell.

In this study, a novel class V flextensional transducer (FT) was developed by assembling symmetrically convex ceramic and metal caps to form a seashell-like structure. The transducer was designed and analyzed using ATILA finite element analysis (FEA) software. The diameter, thickness, and radius of curvature of the ceramic and metal shells have been investigated as design parameters. The transducer was found to display four distinct flextensional modes in addition to the main radial resonance mode between 1 and 200 kHz frequency range. Prototypical devices were fabricated from four different commercial lead zirconate titanate (PZT) compositions and underwater performances were compared. Transmitting voltage responses (TVRs) were observed to range between 120 and 135 dB (ref 1 μ Pa/V) at frequencies above 50 kHz.

Annealing-Dependent Morphotropic Phase Boundary in the BiMg0.5Ti0.5O3-BiZn0.5Ti0.5O3 Perovskite System.

The annealing behavior of (1-x)BiMg0.5Ti0.5O3–xBiZn0.5Ti0.5O3 [(1-x)BMT–xBZT] perovskite solid solutions synthesized under high pressure was studied in situ via X-ray diffraction and piezoresponse force microscopy. The as prepared ceramics show a morphotropic phase boundary (MPB) between the non-polar orthorhombic and ferroelectric tetragonal states at 75 mol. % BZT. It is shown that annealing above 573 K results in irreversible changes in the phase diagram. Namely, for compositions with 0.2 < x < 0.6, the initial orthorhombic phase transforms into a ferroelectric rhombohedral phase. The new MPB between the rhombohedral and tetragonal phases lies at a lower BZT content of 60 mol. %. The phase diagram of the BMT–BZT annealed ceramics is formally analogous to that of the commercial piezoelectric material lead zirconate titanate. This makes the BMT–BZT system promising for the development of environmentally friendly piezoelectric ceramics.

Deformation and bending strength of high‐performance lead‐free piezoceramics

AbstractBending strength of commercially relevant lead‐free piezoceramics – 0.935Na0.5Bi0.5TiO3‐0.065BaTiO3 (NBT‐6.5BT) with and without acceptor Zn‐doping and 0.92(K0.5Na0.5)NbO3‐0.02(Bi0.5Li0.5)TiO3‐xBaZrO3; x = 0.06, 0.07 (KNN‐BZ100x) have been quantified using 4‐point bending tests and contrasted to that of commercial lead zirconate titanate (PZT, PIC151). The compressive and tensile strength probed using additional strain gauges under 4‐point bending indicate negligible non‐linear deformation, in stark contrast to that of commercial PIC151. The bending strength of KNN‐BZ100x is about 100 MPa, comparable to PIC151, while that of NBT‐6.5BT‐based materials is about twice that of PIC151 at ∼160 MPa. These results are rationalized based on the intrinsic characteristics of the lead‐free piezoceramics in terms of fracture toughness, coercive stress, and Young's modulus. Weibull statistics indicate a higher fracture probability for KNN‐based materials, with NBT‐6.5BT‐based materials featuring Weibull modulus twice that of KNN‐based materials.

Design, finite element analysis, fabrication and electroacoustic characterization of transducer arrays from piezoceramics with hollow cylindrical shell form

Electroacoustic transducers arrays operating in the 50–100 kHz frequency range are currently being investigated for underwater applications such as target detection transducers installed on underwater autonomous vehicles (UAV) and detection of underwater intruders to protect and secure economically and strategically critical coastal areas and facilities. However, the frequency range is such that it prevents the use of monolithic piezoceramics operating in the thickness mode due to the unacceptably high voltages that are required to drive them. Whereas the alternative such as Langevin-type transducer solutions have certain other assembly difficulties that arise due to the size limitations imposed on the transducer from the half-wavelength (λ/2) arrangement requirement of the units. In our study, an entirely new alternative was proposed to overcome these difficulties. A piezoceramic transducer constructed from a hollow cylindrical shell form poled in the radial direction was designed and developed to operate at the longitudinal length extension mode. Since the hollow cylindrical piezoceramics were designed and produced with one end closed, this closed end was used as a passive cap with the transducer operating in a piston mode. ATILA finite element analysis code was used to design, analyze and fine-tune the dimensional requirements of the transducer. The center frequency of the transducer was fixed to 70 kHz. Commercial lead zirconate titanate (PZT) composition with hard piezoelectric character (PZT-4) was used as the starting powder. The slip casting method was used to obtain the cylindrical shell form. Single element transducers, as well as a hexagonal close-packed array consisting of seven units and arranged with a distance of half-wavelength (λ/2) to obtain constructive interference at 70 kHz were constructed and tested for underwater electroacoustic performance.

Thermoelectrical Characterization of Piezoelectric Diaphragms: Towards a Better Understanding of Ferroelectrics for Future Memory Applications

This work deals with the thermoelectric characterization of commercial lead zirconate titanate (PZT) based piezoelectric diaphragms. An in-depth analysis of the piezo- and ferroelectric behavior of the samples was carried out by measuring current voltage curves and polarization hysteresis cycles in a wide temperature range. We demonstrate that, as the temperature decreases, higher electric fields are needed to completely polarize the sample. Furthermore, I-V measurements, polarization hysteresis loops and coercive fields allow us to confirm that the samples present different grain sizes. From impedance measurements, resonance frequency values, capacitance and permittivity were determined at temperatures ranging from 100 to 320 K. It is shown that impedance maxima shift towards greater frequency values when decreasing the temperature, which is mainly attributed to the appearance of an internal stress that generates larger stiffness in the ceramic. Finally, an electroacoustic characterization was made by measuring the sound pressure of the diaphragms in the human hearing frequency range.

Ultrahigh piezoelectricity in lead-free piezoceramics by synergistic design

Abstract Following increased environmental concerns on the toxicity of lead, the discovery of ultrahigh piezoelectricity in lead-free piezoelectric materials is critical for the substitution of commercial lead zirconate titanate (PZT) ceramics in numerous electronic devices. In this work, a synergistic design strategy is proposed to enhance the piezoelectricity in lead-free piezoelectric materials by flattening the Gibbs free energy density profile, via the coexistence of multiple phases and local structural heterogeneity. This strategic material design approach is based on first-principles calculations combined with Landau phenomenological theory and phase field simulations. Sustainable Stannum-doped BaTiO3 lead-free ferroelectric ceramics are prepared to validate our proposed mechanism, and a giant piezoelectric coefficient d33 > 1100 pC/N is achieved, being the highest value reported in lead-free piezoceramics. The mechanism and paradigm of the excellent piezoelectricity achieved here provides a feasible solution for replacing lead-based piezoelectrics by lead-free counterparts.

Ceramic materials characterization using miniature mechanical tests: comparison between B3B and SPT tests

Strength of ceramic components is determined by processing, therefore, test methods that allow analysing their actual mechanical behaviour are needed. The miniature mechanical tests ballon three balls (B3B) and small punch (SPT) are compared using commercial lead zirconate titanate (PZT) piezo-ceramic discs. The Weibull distributions of strength were obtained and the fracture surfaces were observed by scanning electron microscopy. The different approaches for the calculation of strength values are discussed.The adequacy of the small punch test for the determination of strength is demonstrated. Results for SPT and B3B tests are comparable considering the effective volumes calculated using the Weibull relationships.The Timoshenko equation for strength is proposed for the calculus of strength due to its simplicity and the fact that the calculated values for B3B and SPT geometries are not dependent on the radius of the uniform loading central area.

A Spray-on, Nanocomposite-Based Sensor Network for in-Situ Active Structural Health Monitoring.

A new breed of nanocomposite-based spray-on sensor is developed for in-situ active structural health monitoring (SHM). The novel nanocomposite sensor is rigorously designed with graphene as the nanofiller and polyvinylpyrrolidone (PVP) as the matrix, fabricated using a simple spray deposition process. Electrical analysis, as well as morphological characterization of the spray-on sensor, was conducted to investigate percolation characteristic, in which the optimal threshold (~0.91%) of the graphene/PVP sensor was determined. Owing to the uniform and stable conductive network formed by well-dispersed graphene nanosheets in the PVP matrix, the tailor-made spray-on sensor exhibited excellent piezoresistive performance. By virtue of the tunneling effect of the conductive network, the sensor was proven to be capable of perceiving signals of guided ultrasonic waves (GUWs) with ultrahigh frequency up to 500 kHz. Lightweight and flexible, the spray-on nanocomposite sensor demonstrated superior sensitivity, high fidelity, and high signal-to-noise ratio under dynamic strain with ultralow magnitude (of the order of micro-strain) that is comparable with commercial lead zirconate titanate (PZT) wafers. The sensors were further networked to perform damage characterization, and the results indicate significant application potential of the spray-on nanocomposite-based sensor for in-situ active GUW-based SHM.

A method to decrease the harmonic distortion in Mn-Zn ferrite/PZT and Ni-Zn ferrite/PZT layered composite rings exhibiting high magnetoelectric effects

We have investigated the magnetoelectric (ME) effect in layered composite rings subjected to circumferential AC magnetic fields and DC magnetic fields in radial, axial, or circumferential directions. Bilayer samples were obtained combining different grades of commercial Mn-Zn ferrites or Ni-Zn ferrites with commercial lead zirconate titanate (PZT). Mn-Zn ferrites with low magnetostriction saturation (λs&amp;lt;10−6) and low magneto-crystalline anisotropy constants show high ME capabilities when associated with PZT in ring structures. In certain conditions, these ME effects are higher than those obtained with Terfenol-D/PZT composites in the same layered ring structure. Magnetostrictive and mechanical characterizations have given results that explain these high ME performances. Nevertheless, Mn-Zn ferrite/PZT composites exhibit voltages responses with low linearity especially at high signal level. Based on the particular structure of the ME device, a method to decrease the nonlinear harmonic distortion of the ME voltages is proposed. Harmonic distortion analysis of ME voltages measured in different configurations allows us to explain the phenomenon.

Piezoelectric materials for high temperature transducers and actuators

Piezoelectric sensors and actuators are a mature technology, commonplace amongst a plethora of industrial fields including automotive, maritime and non-destructive testing. However the environments that these devices are required to serve in are becoming more demanding, with temperatures being driven higher to increase efficiencies and reduce shut-downs. Materials to survive these temperatures have been the focus of many research groups over the last decade, but there still remains no standard for the measurement of piezoelectric materials at high temperature. This is required to effectively determine comparable Figures of Merit into which devices can be successfully designed. As part of a recent European effort to establish metrological techniques for high temperature evaluation of electro-mechanical properties, we present here a review of the most promising high temperature polycrystalline materials. Where their properties allow operation above that of the ubiquitous commercial material lead zirconate titanate, as well as work done to modify a promising high temperature system, for use as a material standard.

Enhanced extrinsic domain switching strain in core–shell structured BaTiO3–KNbO3 ceramics

Large electric-field-induced strain in piezoelectric ceramics is a primary requirement for their actuator applications. This macroscopic strain is generated from both intrinsic lattice strain and extrinsic domain switching and/or phase transformations. Among these contributions, non-180° ferroelectric domain switching can generate a large electric-field-induced strain due to the change in orientation of the coupled spontaneous strain. However, the large fraction of non-180° ferroelectric domain switching is a one-time effect during electrical poling. Here, we show that electric-field-induced non-180° ferroelectric domain switching in the microstructurally engineered material BaTiO3–KNbO3 (BT–KN) is largely reversible. In situ high energy X-ray diffraction showed approximately 95% reversibility in the switched fraction of non-180° ferroelectric domains during unipolar cycling. This reversibility is hypothesised to be due to the unique grain boundary structure of this material, where ferroelectric domain walls do not interact strongly with grain boundary defects. The domain switching behaviour of core–shell BT–KN has been contrasted with that of polycrystalline BaTiO3 and commercial lead zirconate titanate Pb(Zr,Ti)O3. The large and reversible non-180° ferroelectric domain switching of core–shell BT–KN offers a distinctive strain response. The results indicate a unique family of large strain lead-free materials based on enhanced reversible non-180° ferroelectric domain switching can be developed for future actuator applications.

Magnetoelectric effect in layered ferrite/PZT composites. Study of the demagnetizing effect on the magnetoelectric behavior

We report the use of high magnetomechanical coupling ferrites in magnetoelectric (ME) layered composites. Bilayer samples combining (Ni0.973 Co0.027)1−xZnxFe2O4 ferrites (x = 0–0.5) synthesized by non conventional reactive Spark Plasma Sintering and commercial lead zirconate titanate (PZT) were characterized in term of ME voltage coefficients measured at sub-resonant frequency. Strong ME effects are obtained and we show that an annealing at 1000 °C and a quenching in air improve the piezomagnetic behavior of Zn-rich compositions. A theoretical model that predicts the ME behavior was developed, focusing our work on the demagnetizing effects in the transversal mode as well as the longitudinal mode. The model shows that: (i) high ME coefficients are obtained when ferrites with high magnetomechanical coupling are used in bilayer ME composites, (ii) the ME behavior in transversal and longitudinal modes is quite similar, and differences in the shapes of the ME curves are mainly due the demagnetizing effects, (iii) in the transversal mode, the magnetic field penetration depends on the ferrite layer thickness and the ME coefficient is affected accordingly. The two later points are confirmed by measurements on ME samples and calculations. Performances of the ME composites made with high magnetomechanical coupling ferrites are compared to those obtained using Terfenol-D materials in the same conditions of size, shape, and volume ratio. It appears that a ferrite with an optimized composition has performances comparable to those obtained with Terfenol-D material. Nevertheless, the fabrication processes of ferrites are quite simpler. Finally, a ferrite/PZT based ME composite was used as a current sensor.

Pyroelectric energy harvesting devices based-on Pb[(MnxNb1−x)1/2(MnxSb1−x)1/2]y(ZrzTi1−z)1−yO3 ceramics

The energy conversion and harvesting properties of pyroelectric devices depend on many aspects, including the properties of pyroelectric materials, the structure of the devices, and so on. In this work, the capability of harvesting energy using Pb[(MnxNb1−x)1/2(MnxSb1−x)1/2]y(ZrzTi1−z)1−yO3 (PMnN–PMS–PZT) ceramics was studied. For this purpose, three different Zr/Ti compositions, i.e. 94/6, 95/5 and 96/4 (in molar ratio) of the ceramics were prepared and characterized. The ceramic with 95/5 of Zr/Ti was found to have optimized pyroelectric properties and consequently used to fabricate pyroelectric energy harvesting devices. Three different device configurations, including a monolithic ceramic, ceramic arrays and multilayered ceramics were studied, and the innovated multilayered ceramic structure proposed in this study showed advantages in energy conversion and collection efficiency, which were evaluated by using an oven and a Peltier cell as heating and cooling methods. The maximum densities of surface charge achieved for the three types of ceramic structures are 7.19×10−6C/cm2, 6.59×10−6C/cm2, 1.55×10−5C/cm2, respectively, which are in general higher than that of the commercial lead zirconate titanate (PZT-5H). We also investigated the effects of temperature change frequency on the electrical response by using the monolithic ceramic device as an example. At an operating frequency of 70mHz, the pyroelectric device shows an induced energy as high as 2.873μJ and a power density of 4.857mW/cm3. The obtained results indicate that our proposed PMnN–PMS–PZT devices in general has a better pyroelectric performance than the commercial lead zirconate titanate (PZT-5H) pyroelectric devices, and may have potential applications in ultra-low-power devices and in wireless network systems.

Effect of Polarization on Mechanical Properties of Lead Zirconate Titanate Ceramics

This study concerns two following commercial lead zirconate titanate (PZT) materials, PZT-5H and PZT-8 piezoelectric ceramics. Young's modulus and internal friction versus temperature at different vibration frequencies were investigated by means of Dynamic Mechanical Analysis (DMA) before and after polarization. The phase transition temperatures (Tc) of PZT-5H and PZT-8 ceramics were 438 K and 550 K. PZT-8 ceramic had higher Young's modulus than PZT-5H ceramic at ferroelectric phase, which resulted from the increase of internal local stress in PZT-8 ceramic. After polarization, the Young's modulus of both PZT ceramics increased, the influence of the piezo- electric effect was investigated. A relaxation peak emerges in internal friction curve of each PZT sample. Considering the hard ceramic, this peak is a pure relaxation mechanism controlled by oxygen vacancies diffusion. Considering the soft ceramic, the relaxation peak can be related to viscous motion of domain walls and the interaction between domain walls and point defects. The activation energy of the relaxation peak increased after polarization, which resulted from the increased local internal stress and directional arranged space charges caused by polarization.

Acoustic emission detection and position identification of transverse cracks in carbon fiber–reinforced plastic laminates by using a novel optical fiber ultrasonic sensing system

Utilizing optical fiber technique to structural health monitoring of composite materials is attracting attention recently due to the inherent advantages in optical fiber sensor. However, acoustic emission signals with low energy and high frequency from transverse cracks in carbon fiber–reinforced plastic laminates are difficult to be detected by normal optical techniques. In this work, we present a phase-shifted fiber Bragg grating balanced sensing system to detect acoustic emission signals generated in a carbon fiber–reinforced plastic laminate in a three-point bending test. We demonstrated that the phase-shifted fiber Bragg grating balanced sensing system with a broad bandwidth and high sensitivity can detect high-frequency, low-energy acoustic emission signals caused by transverse cracks. In our experiments, the transverse cracks were identified very well through the detected acoustic emission signals. The relationship between the strain and the acoustic emission signals, and the typical waveforms of the acoustic emission signals were investigated. Furthermore, accurate position identification using acoustic emission detection by the phase-shifted fiber Bragg grating sensor was demonstrated. All the results obtained from the phase-shifted fiber Bragg grating sensor were compared to the results obtained from commercial lead–zirconate–titanate acoustic emission sensors. We found that the phase-shifted fiber Bragg grating balanced sensing system performance was comparable to the commercial lead–zirconate–titanate acoustic emission sensors.

Evaluation of electromechanical coupling parameters of piezoelectric materials by using piezoelectric cantilever with coplanar electrode structure in quasi-stasis

Based on Timoshenko beam theory, a principle model is proposed to establish the relationship between electric charge and excitation acceleration, and in quasi-stasis we apply the direct piezoelectric effect of multilayer cantilever with coplanar electrode structure to evaluate the piezoelectric strain coefficient d15 and electromechanical coupling coefficient k15. They are measured as 678 pC/N and 0.74 for the commercial piezoelectric ceramic lead zirconate titanate (PZT-51) bulk specimen and 656 pC/N and 0.63 for the lead magnesium niobate (PMN) bulk specimen, and they are in agreement with the calibration and simulation values. The maximum of relative errors is less than 4.2%, so the proposed method is reliable and convenient.

Identification of process parameters for efficient poling of PZT ceramics for mass production

Advanced, cost–effective and series compatible manufacturing of active structural components demands for short production times and complex multi-material designs. Highest efficiency is achieved when integrating the poling process of the piezoceramic that activates the piezoelectric effect into the manufacturing chain. The present paper reports on first results of the systematic evaluation of parameters governing the poling regime of commercial lead zirconate titanate (PZT) ceramics. It aims to find the conditions for efficient poling of the active material as an integrated technology step in mass production. In the present investigation, the influence of poling field strength and temperature on the obtained remanent polarization is considered by varying the temperature from −175 °C to 150 °C and the electric poling field strength from 1.0 to 2.0 kV/mm. Six commercially available piezoceramic materials, primarily used in actuator applications, were investigated. From the findings, it was possible to deduce technological parameters for an efficient poling process.

Piezoelectric bimorph-based scanner in the tip-scan mode for high speed atomic force microscope

A piezoelectric bimorph-based scanner operating in tip-scan mode for high speed atomic force microscope (AFM) is first presented. The free end of the bimorph is used for fixing an AFM cantilever probe and the other one is mounted on the AFM head. The sample is placed on the top of a piezoelectric tube scanner. High speed scan is performed with the bimorph that vibrates at the resonant frequency, while slow scanning is carried out by the tube scanner. The design and performance of the scanner is discussed and given in detailed. Combined with a commercially available data acquisition system, a high speed AFM has been built successfully. By real-time observing the deformation of the pores on the surface of a commercial piezoelectric lead zirconate titanate (PZT-5) ceramics under electric field, the dynamic imaging capability of the AFM is demonstrated. The results show that the notable advantage of the AFM is that dynamic process of the sample with large dimensions can be easily investigated. In addition, this design could provide a way to study a sample in real time under the given experimental condition, such as under an external electric field, on a heating stage, or in a liquid cell.

Effects of the Poling Process on Piezoelectric Properties in Lead Zirconate Titanate Ceramics

The influence of ferroelectric poling temperature and electric field amplitude on the piezoelectric coefficient d33 is investigated in a commercial lead zirconate titanate ceramic. A strong dependence of the electric field amplitude on the direct d33 coefficient is observed. The converse d33 piezoelectric coefficient of samples poled at specific conditions is measured and interpreted in the context of Rayleigh Law. Samples poled at higher temperatures and electric fields exhibit both a higher direct d33 coefficient and a higher extrinsic contribution to the converse d33 coefficient than samples which are less highly poled. Possible microstructural origins for this behavior are discussed.