PLZT Ceramics Research Articles

Twin phase symmetry and multifunction features of PLZT (7/60/40) ceramics

Here, we report the effect of 7 wt% La substitution at the Pb-site of PZT (60/40), resulting in PLZT (7/60/40) prepared by solid-state reaction technique. The powder X-ray diffraction (XRD) taken at room temperature revealed the coexistence of tetragonal and rhombohedral (T+R) crystal structures having P4mm and R3c space groups. Scanning electron micrograph (SEM) showed the inhomogeneous distribution of quasi-cubical grains with a grain size range of 0.5–1.15 μm. Energy dispersive X-ray analysis (EDS) showed well-resolved peaks of all elements present, and a dielectric peak observed at 220 °C exhibited diffused ferroelectric-paraelectric phase transition of PLZT (7/60/40). The AC conductivity, impedance studies, and the conduction mechanism based on large and small polaronic movements are discussed. The semiconductor to metal transition and a ferroelectric relaxor kind feature were observed in the studied compound. The observed value of bipolar strain is ∼0.2 %, and unipolar is ∼0.18 %. The remnant polarization (Pr) and coercive field (Ec) are ∼ 20 (μC/cm2) and ∼ 13.5 (kV/cm), respectively, in both loops. We calculated large-signal piezoelectric coefficient d33* of ∼600pmV–1. A compact multilayer actuator was fabricated by a stacking method using pellets of PLZT.

Manipulating Zr/Ti ratio based on phase diagram for large electrocaloric effects with multiple target operation temperatures in PLZT ceramics

Manipulating Zr/Ti ratio based on phase diagram for large electrocaloric effects with multiple target operation temperatures in PLZT ceramics

Optically controlled variable damping system based on PLZT ceramic/ERF in rectangular microchannel

Variable damping control technology based on intelligent materials of electromagnetic excitation has been widely used in the field of (semi-) active vibration control and fluid control. Unfortunately, a major drawback is the electromagnetic noise interference and low response speed. In this paper, a new optically controlled variable damping system based on PLZT ceramic/electrorheological fluid (ERF) is proposed. The mathematical models of the photovoltage generated by PLZT ceramics and the pressure difference between the two ends of the microchannel are established and verified by numerical simulation in COMSOL Multiphysics. Meanwhile, with the increase of light intensity, liquid flow rate and decrease of microchannel height and width, the pressure difference shows an uptrend. Optically controlled variable damping system based on PLZT ceramic/ERF is a control method with the advantages of a clean excitation source, remote control, no electromagnetic interference, and fast response speed, and has a good application prospect in the field of vibration control and fluid control.

Effect of annealing atmosphere on the energy storage performance of antiferroelectric ceramics PLZT

Effect of annealing atmosphere on the energy storage performance of antiferroelectric ceramics PLZT

Investigation of Praseodymium Ions Dopant on 9/65/35 PLZT Ceramics’ Behaviors, Prepared by the Gel-Combustion Route

In this work, were synthesized (Pb0.91La0.09)(Zr0.65Ti0.35)0.9775O3 ceramic materials with different concentrations of praseodymium (0, 0.1, 0.3, 0.5, 1 wt.%) via gel-combustion route and sintered by the hot uniaxial pressing method. Measurements were conducted on the obtained ceramics using X-ray powder diffraction (XRD), scanning electron microscope (SEM), EDS analysis, and examination of dielectric and ferroelectric optical properties. Results give us a detailed account of the influences of the praseodymium ions on the structural, microstructural, and dielectric properties. 3D fluorescence maps and excitation and emission spectra measurements show how a small admixture changes the ferroelectric relaxor behavior to an optically active ferroelectric luminophore.

Structural and electrical properties of PLZT x/65/35 ceramics prepared via mechanical activation method near the morphotropic phase boundary

This paper reports the effect of lanthanum addition on the structural and electrical properties of (Pb1-xLax)(Zr0.65Ti0.35)O3 (PLZT x/65/35, x = 8%,10%,12%,15%) ceramics near the morphotropic phase boundary. Studies were conducted on the PLZT x/65/35 ceramics synthesized via a combinatorial approach of high-energy ball milling (mechanical activation method) followed by Cold Isostatic Pressing (CIP). Due to the application of CIP, PLZT ceramics exhibited improved density and a closely packed microstructure. The SEM analysis showed that PLZT x/65/35 ceramics exhibited an increase in grain size with higher concentrations of La3+ ions. Room temperature X-ray diffraction results revealed the formation of perovskite PLZT phase. The investigation on temperature-dependent dielectric, ferroelectric properties of PLZT x/65/35 ceramics provided experimental confirmation of structures cited in XRD analysis. Among all the compositions, PLZT 8/65/35 samples showed a well saturated, uniform P–E hysteresis loop with a high remanent polarization (Pr). Poled PLZT 8/65/35 samples displayed electric field induced large strains with limited hysteresis. Piezoelectric charge coefficients (d33), electromechanical coupling factors (kp, k33, k31) were determined for poled PLZT x/65/35 ceramics and it was found that PLZT 8/65/35 ceramics reveal properties superior to other compositions. Furthermore, the unipolar strain, Pr, d33, kp, k33, k31 values of PLZT 8/65/35 composition exceeded the previously reported ones for the same composition prepared via sol-gel synthesis technique.

Sintering pressure of SPS-inducing lattice deformation enhances ferroelectric and photoluminescence properties of PLZT ceramics

Sintering pressure of SPS-inducing lattice deformation enhances ferroelectric and photoluminescence properties of PLZT ceramics

Multiphysics Modeling and Simulation of a Light-Controlled Variable Damping System.

In this paper, a light-controlled variable damping system (LCVDS) is proposed based on PLZT ceramics and electrorheological fluid (ERF). The mathematical models for the photovoltage of PLZT ceramics and the hydrodynamic model for the ERF are established, and the relationship between the pressure difference at both ends of the microchannel and the light intensity is deduced. Then, simulations are conducted by applying different light intensities in the LCVDS to analyze the pressure difference at both ends of the microchannel using COMSOL Multiphysics. The simulation results show that the pressure difference at both ends of the microchannel increases with the increase in light intensity, which is consistent with results from the mathematical model established in this paper. The error rate of the pressure difference at both ends of the microchannel is within 13.8% between the theoretical and simulation results. This investigation lays the foundation for the application of light-controlled variable damping in future engineering.

Effects of La<sup>+3</sup> and Sc<sup>+3</sup> Ions on Structure and Microstructure of PZT Ceramics for Energy Storage Applications

Solid solutions of PZT ceramic at Zr/Ti ratio of 0.56/0.44 having various content of softener (La+3) and hardener (Sc+3) ions according to chemical formula (Pb1-y Lay) (Scx Zr0.56-x Ti0.44) O3, [y= (0.0 and 0.02); x= (0.02, 0.04 and 0.06)], were prepared via conventional solid state reaction methods. Structural and microstructural characteristics were investigated systematically. The measurements of XRD diffraction spectra showed occurring of phase transformation after doping with Sc+3 ions in both, PZT and PLZT ceramics, through emerging of tetragonal phase to coexist with the rhombohedral phase. Their fraction varied depending on content of Sc+3 ions. SEM mages display a different influence of softener and hardener ions, at 0.02 % mole, on the grain size. Doping with La+3 causes reduction in grain size, whereas Sc+3 increase the grain size. However, further increase in Sc+3 content in both (PZT and PZT) ceramics causes sharp decreasing in grain size. The latter feature is preferable in terms of increasing in the energy storage values.

Strain Characteristics of PLZT-Based Ceramics for Actuator Applications

Lead lanthanum zirconate titanate (PLZT) ceramics exhibit excellent dielectric, ferroelectric and piezoelectric properties, and they can be used in many applications, including actuators. In this review, the processing and properties of PLZT-based ceramics will be the main focus of the first part. An introduction to PLZT ceramics is given and the methods to improve processing of PLZT-based ceramics are explained in terms of the addition of sintering aids, fabrication in the form of composites, and the application of dopants. The second part will be related to strain measurement to investigate converse piezoelectric properties (actuating effect). Strain measurement techniques by Michelson interferometry and case studies in PLZT-based ceramics (aging effect, temperature dependence and magnetic field effect) are included.

Neodymium and samarium codoped PLZT ferroelectric ceramics for potential betavoltaic nuclear batteries

In this work, neodymium (Nd) and samarium (Sm) codoped lead lanthanum zirconate titanate (PLZT) ceramics were prepared by a high-temperature solid-state method. The samples were characterized by X-ray diffraction, scanning electron microscopy and ferroelectric analysis. Rare earth-doped PLZT ceramics show good phase formation. An appropriate rare earth element doping amount increases the densities of PLZT ceramics and reduces their resistivities, which is due to the role of rare earth elements in grain refinement. However, the increase in the amount of grain boundaries caused by grain refinement also affects domain inversion. Therefore, with increasing doping concentration, the remnant polarization of PLZT gradually decreases, and the doping of rare earth elements also slightly reduces the band gap of PLZT. Under irradiation with an X-ray simulated beta source with a particle energy of 10 keV (between the average energies of the beta particles of 3H and 63Ni), the ceramic sheets in this work produce current densities of up to 1.38 nA/cm2. This indicates that Nd and Sm codoped PLZT ceramics have a certain potential for application in betavoltaic batteries.

Elasto‐Optic Effect of Lanthanum‐Modified Lead Zirconate–Lead Titanate Transparent Ceramics: Application in Optical‐Stress Sensors

AbstractElasto‐optic materials have extensive applications, particularly in sensors, filters, and acousto‐optic modulators in optical–mechanical‐coupled devices. Ferroelectric phenomenological theoretical analyses have shown that materials with large ferroelastic responses also have high elasto‐optic effects, and morphotropic phase‐boundary (MPB) ferroelectrics have substantial ferroelastic coupling; thus, a large elasto‐optic effect can be obtained. In this study, guided by phenomenological theories, lanthanum‐modified lead zirconate–lead titanate (PLZT) transparent ceramics close to MPB are successfully prepared using the hot‐pressing method. The elasto‐optic properties of the PLZT transparent ceramics are investigated using the half‐wave stress and the Sénarmont compensator methods. The results indicate that the PLZT ceramics have high transmittance (higher than 70% in near‐infrared) and a large elasto‐optic effect with a stress‐optic coefficient of 10.41 × 10−12 m2 N−1 (approximately three times that of SiO2). Based on these properties, intensity‐ and interference‐type optical‐stress sensors are designed and realized; better anti‐interference ability can be achieved using the interference‐type sensor. These results indicate that PLZT transparent ceramics are promising candidates for optical–mechanical‐coupled device applications. This study also substantiates that transparent ceramics are novel elasto‐optic materials, which uncover new avenues for the development of elasto‐optic materials with excellent properties.

Impact of annealing on electrocaloric response in Lanthanum-modified lead zirconate titanate ceramic

Over the past decades, there has been significant interest in new cooling technology based on the large electrocaloric effect observed in polymeric and inorganic ferroelectric materials. We report a dramatic impact of annealing on the electrocaloric effect observed by direct measurements in Pb0.88La0.12(Zr0.65Ti0.35)0.97O3 bulk ceramics (12/65/35 PLZT). In addition, the EC response was measured deep in a relaxor part of the PLZT composition phase diagram. After additional one-hour sample annealing at 600 °C, the EC response increased by about six times. Electrocaloric results confirm the existence of the significant electrocaloric response with the EC temperature change (ΔTEC) of 4.5 K at 360 K and 90 kV/cm in an annealed sample. This value exceeds previously obtained maximum ΔTEC values at the same field in perovskite relaxor ferroelectrics such as Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) and 8/65/35 PLZT ceramics. The electrocaloric responsivity ΔT/ΔE = 5.09 × 10−7 Km/V determined at 360 K is among the highest observed in bulk perovskite ferroelectrics at a relatively high electric field of 90 kV/cm.

Effect of sintering temperature on phase formation and dielectric property of modified PLZT ceramics with addition of BT and PZN

ABSTRACT The modified-lead lanthanum zirconate titanate (PLZT) ceramics with the addition of barium titanate (BT) and lead zinc niobate (PZN) were prepared. PLZT 9/65/35–BT ceramics changed from ferroelectric rhombohedral phase to paraelectric cubic phase as the content of BT was increased. The optimized dielectric constant at room temperature and frequency of 1 kHz could be obtained when 5 mol% BT was added and the ceramic was sintered at 1275 °C (ϵr = 10463, tanδ = 0.0125). PLZT 8/40/60–PZN ceramics had a perovskite structure with a decrease of unit cell volume as the content of PZN was increased. The optimized dielectric constant at room temperature and frequency of 1 kHz could be obtained when 20 mol% PZN was added and the ceramic was sintered at 1250 °C (ϵr = 14290, tanδ = 0.0081).

Enhanced pressure‐driven force‐electric conversion effect for (Pb,La)(Zr,Ti)O3ferroelectric ceramics

AbstractThe pressure‐driven force‐electric conversion materials with extremely rapid response time have been widely used in mining, defense, and energy areas. The discharge process by the force‐electric conversion effect in ferroelectrics is dominated by polar‐nonpolar phase transformation. In this work, (Pb0.985La0.01)(ZrxTi1‐x)O3(PLZT,x = 0.85–0.94) ceramics is designed by tunning Zr4+/Ti4+ratio and aliovalent La doping to achieve high remnant polarization (Pr) and excellent temperature stability. We focus on the pressure‐driven depolarization in PLZT ceramics, and their corresponding phase structure, ferroelectric properties, dielectric properties, and thermal depolarization. In PLZT (x = 0.93) ceramics, the original polarizationP0increases to 43.42 μC/cm2. The pressure‐driven depolarization releases 37.66 μC/cm2with the depolarization proportion of 86.73%, which is attributed to irreversible ferroelectric‐antiferroelectric phase transition. It also exhibits excellent temperature stability up to 120°C (> 36 μC/cm2). This work provides a high‐performance alternative to Pb(Zr0.95Ti0.05)O3and guidance for the development of pulse power energy conversion devices.

Crystallization and Morphology of Pb0.92La0.08(Zr0.68Ti0.32)0.98O3 Powders Synthesized Using the Gel‐Hydrothermal Process

AbstractPure perovskite Pb0.92La0.08(Zr0.68Ti0.32)0.98O3 (PLZT (8/68/32)) crystal powders with good dispersibility are prepared by using gel‐hydrothermal method. The effects of mineralizer concentration, hydrothermal treatment time, and excess lead content on powder crystallization and morphology are examined and analyzed. The suitable mineralizer concentration and hydrothermal treatment time are found to be helpful to promote the PLZT crystal powders growth and improve the particle surface morphology. Noticeably, the introduction of excessive Pb can well compensate for the lack of A‐site ions in the solution, thereby promoting the formation of rhombohedral PLZT crystal powders. The following optimized hydrothermal conditions are established: the temperature ≈230 °C, the mineralizer concentration ≈2 m, the hydrothermal treatment time ≈24 h, and the amount of excess Pb ≈ 80%. The obtained PLZT crystal powders with clean and complete cube morphology, uniform particle size, and excellent dispersibility would be used as the crystal seeds applying in the seed‐induced growth of PLZT ceramics.

Enhancing piezoelectricity of PLZT ceramics by bismuth stearate coating via water-soluble defatted powder injection molding

Lead zirconate titanate-based piezoelectric ceramics (Pb0·91La0·06(Zr0·58Ti0.42)0.975Nb0·02O3, PLZT) were prepared by water-soluble defatted powder injection molding using bismuth stearate as surfactant. The effects of bismuth stearate surfactant amount on the feed viscosity, water degreasing rate and electrical properties were studied. The results showed that the bismuth stearate coating reduces agglomeration between the PLZT powders and decreases the viscosity of the feed. During sintering, bismuth stearate is decomposed into bismuth oxide, which acts as sintering aid to increase the density of the sintered bismuth stearate-coated PLZT ceramics. Bi3+ dissolves into the perovskite crystal lattice, which increases the tetragonality factor and the content of tetragonal phase, and improves the dielectric, ferroelectric and piezoelectric properties of the bismuth stearate-coated PLZT ceramics. This study provides a novel modification method for the production of injection molded ceramics using a water-soluble binder system.

Effect of soaking times on ferroelectric properties and strain behavior of PLZT ceramics

In this work, PLZT x/65/35 powders where x=4, 6, 8 and 10 mol% were prepared by mixed-oxide method and sintered at 1200 °C for 4, 8 and 12h. The electric field induced strain (S-E) and electric field induced polarization (P-E) were measured by using strain and polarization measurement system. It was found that PLZT 6/65/35 had the optimized condition with the soaking time of 12h. The highest remnant polarization (18.24 μC/cm2), saturated polarization (24.73 μC/cm2), strain (0.4090%) and d* 33 (204.50 pm/V) It can be concluded that the soaking times affected to ferroelectric properties and strain behavior.

A novel vacuum/oxygen hot press sintering approach for the fabrication of transparent PLZT (7.4/70/30) ceramics

Transparent Lanthanum-modified lead zirconate titanate ceramics (PLZT 7.4/70/30) with low content of excess lead oxide (PbO) were successfully prepared by a novel vacuum/oxygen hot press sintering process. The phase structure, microstructure, electrical properties and electro-optic scattering performance of PLZT ceramics as a function of excess PbO in the starting powders have been studied and analyzed. As a result, these ceramics exhibited an ultra-high optical transmittance (>69.4% at 1064 nm; thickness 1 mm) from visible to near-infrared wavelength. Herein, we significantly reduce the use of PbO as an auxiliary agent for sintering. This puts forward a good route to meet the objectives of environmental protection and sustainable development.

Investigation of the Effects of Reduced Sintering Temperature on Dielectric, Ferroelectric and Energy Storage Properties of Microwave-Sintered PLZT 8/60/40 Ceramics

In this study, (Pb0.92La0.08) (Zr0.60Ti0.40) O3 (PLZT 8/60/40) ceramics were synthesized using a high-energy ball-milling technique followed by microwave sintering at different temperatures from 900 °C to 1200 °C. The optimal microwave sintering temperature for the PLZT 8/60/40 ceramics was found to be 1150 °C, which is relatively low compared with conventional sintering temperature. The sintered ceramics show the pure perovskite phase, uniform grain microstructure (1.2 µm) and high density (~99.5%). The polarization vs. electric field (P-E) hysteresis curves were used to investigate the ferroelectric and energy storage properties. The switching characteristic in P-E loops and occurrence of domain switching current in current vs. electric field (I-E) loops confirms their ferroelectric nature. The PLZT ceramics, which were sintered at 1150 °C, show the highest remnant polarization (Pr) of ~32.18 μC/cm2 and domain switching current (Imax) of ~0.91 mA with a low coercive field (Ec) of ~10.17 kV/cm. The bipolar and unipolar strain vs. electric field (S-E) hysteresis loops were also measured and the highest unipolar strain was found to be ~0.26% for the PLZT ceramics sintered at 1150 °C. The unipolar S-E curves were used to derive the piezoelectric coefficient (d33~495 pm/V) and a strain hysteresis loss (~5.8%).