Textured Piezoelectric Ceramics Research Articles

Three-dimensional honeycomb structured BaTiO3-based piezoelectric ceramics via texturing and vat photopolymerization

Textured piezoelectric ceramics have attracted significant attention due to their ability to achieve ultra-high piezoelectric properties comparable to single crystals at a lower cost. Traditional processing techniques, such as tape casting, can efficiently produce textured piezoelectric ceramics with simple structures but are inadequate for fabricating three-dimensional structures with high complexity, thereby limiting their applications in specific fields. Vat photopolymerization (VPP), an advanced additive manufacturing technology, can rapidly and accurately create intricate three-dimensional structures. Crucially, VPP can provide the necessary shear force to align the templates, resulting in the highly-textured piezoelectric ceramics. In this study, BaTiO3-based piezoelectric ceramics with a high degree of texture (97.2 %) were produced using VPP technology. These ceramics exhibited a large piezoelectric coefficient (d33 = 511 pC/N), which was 66 % higher than that of non-textured ceramics. Furthermore, textured ceramics with a honeycomb structure were fabricated, demonstrating their potential in sensing applications. This work confirms the feasibility of using VPP technology to prepare high-performance, complex-structured textured ceramics, thereby promoting the development and application of textured piezoelectric ceramics.

Research progress in the study of textured piezoelectric ceramics

Piezoelectric ceramics have the advantages of uniform composition, excellent performance, good electromechanical coupling performance, and high cost performance. They are currently one of the important materials for manufacturing sensors and semiconductor components on the market. Although piezoelectric ceramic materials are widely used because of their many advantages, how to improve their piezoelectric properties is still a hot and difficult research spot. Previously, the piezoelectric properties of piezoelectric ceramics were affected by adjusting the grain size, but due to its limited enhancement effect, researchers hope to find other ways to improve the piezoelectric properties of ceramics more efficiently. Research has found that texture process can enable isotropic ceramics to obtain similar characteristics to single crystals that exhibit anisotropy. This greatly improves the piezoelectric properties of ceramics. During the texture process, the type and content of the template, texture degree and texture orientation, and other factors will significantly affect the piezoelectric properties of textured ceramics. With the continuous development of texture technology and process, the piezoelectric properties of textured ceramics have been significantly improved, but the practical application is less. Based on this, this article expounds the design principles of textured ceramics, summarizes the progress in the preparation of textured piezoelectric ceramics, and systematically explains the importance of template and texture orientation selection in texture processing. Finally, this paper also analyses the application of textured ceramics, and looks forward to the optimization methods and development prospects of piezoelectric ceramics. It is hoped to help the application and development of piezoelectric ceramics.

Structural characteristics and crystalline nature of PZT powders topochemically synthesized from needle-like TiZrO4 precursors

Pb(Zr0.5Ti0.5)O3 (PZT) powders were synthesized from needle-like TiZrO4 (TZO) precursors by topochemical molten salt synthesis. The effects of the flux types, the raw powder sizes and the synthesis temperatures on the resultant particle morphologies and phase structures of both TZO and PZT were investigated. Via optimizing the synthesis conditions, needle-like TZO with a smooth surface and needle-like PZT with a rough surface were obtained. Transmission electron microscopy (TEM) analyses unveiled that TZO possesses a single-crystal structure with the axial direction along the [010] crystallographic orientation, while PZT exhibits a polycrystalline structure with a discernible degree of misorientation. Notably, the synthesized needle-like PZT from TZO were observed to be unstable and could not induce oriented grain growth of Pb(Mg1/3Nb2/3)O3-PbZrO3-PbTiO3 (PMN-PZT) ceramics. This study reveals that improving the thermal stability of needle-like PZT seeds is one of the key factors for the templated grain growth in textured piezoelectric ceramics.

Excellent strain and temperature stability in PNT-PZT multilayer textured ceramics

A new ceramic system, Pb(Ni1/3Ta2/3)O3-PbZrO3-PbTiO3(PNT-PZT), was found to be able to be textured at low temperatures (≤ 1000 °C) without the addition of sintering aids. Textured 0.24PNT-0.34PZ-0.42PT ceramics with different template contents were successfully prepared at 1000 °C using BaTiO3 platelets as templates. The phase structure, microstructure, electrical properties and strain-temperature stability of the ceramics were studied in detail. The 0.24PNT-0.34PZ-0.42PT-5 vol% BT ceramic has the best comprehensive properties (d33 = 820 pC/N, εr = 2499, EC = 6.25 kV/cm， TC = 180 °C) and excellent temperature stability (strain variation ≤ 5% between 20 °C and 140 °C). Finally, multilayer textured piezoelectric ceramics were prepared and their displacement output characteristics were studied. The multilayer piezoelectric ceramics successfully exhibit excellent strain under small voltage driving. Our work provides a new candidate material for the development of a new generation of multilayer piezoelectric ceramics.

Direct ink writing of textured piezoelectric ceramics

Textured ceramics are often formed via tape casting in order to align platelet particles in the preferred direction, allowing the ceramic to have properties approaching those of single crystals without the complexities of growing such a crystal. However, tape casting produces significant waste material, as flat plates are machined to produce the desired geometries, e.g., rings. Additive manufacturing reduces these issues by allowing the complex geometries to be formed in the green state, thus reducing waste and improving design freedom. This presentation will discuss progress to-date on direct ink writing (DIW) of textured PMN-PZT. The focus will be on the methodology used to develop a suitable paste for printing. Development of a stable, shear thinning paste with a quick recovery time is critical. Zeta potential and rheological data were collected as a function of pH and other relevant slurry parameters such as percent solids loading and binder content. Sintered filaments and bulk parts were characterized to evaluate the efficacy of template alignment in the process as a function of slurry rheology, nozzle geometry, and print parameters.

High-power piezoelectric behavior of acceptor-doped 〈001〉 and 〈111〉 textured piezoelectric ceramics

The high-power piezoelectric properties of MnO2-doped 〈001〉 and 〈111〉 textured 0.24PIN–0.42PMN–0.34PT ceramics are compared to understand the orientation dependence.

Water Quenched and Acceptor-Doped Textured Piezoelectric Ceramics for Off-Resonance and On-Resonance Devices.

Piezoelectric materials should simultaneously possess the soft properties (high piezoelectric coefficient, d33 ; high voltage coefficient, g33 ; high electromechanical coupling factor, k) and hard properties (high mechanical quality factor, Qm ; low dielectric loss, tan δ) along with wide operation temperature (e.g., high rhombohedral-tetragonal phase transition temperature Tr-t ) for covering off-resonance (figure of merit (FOM), d33 × g33 ) and on-resonance (FOM, Qm × k2 ) applications. However, achieving hard and soft piezoelectric properties simultaneously along with high transition temperature is quite challenging since these properties are inversely related to each other. Here, through a synergistic design strategy of combining composition/phase selection, crystallographic texturing, defect engineering, and water quenching technique, <001> textured 2mol% MnO2 doped 0.19PIN-0.445PSN-0.365PT ceramics exhibiting giant FOM values of Qm × (227-261) along with high d33 × g33 (28-35 × 10-12 m2 N-1 ), low tan δ (0.3-0.39%) and high Tr-t of 140-190°C, which is far beyond the performance of the state-of-the-art piezoelectric materials, are fabricated. Further, a novel water quenching (WQ) room temperature poling technique, which results in enhanced piezoelectricity of textured MnO2 doped PIN-PSN-PT ceramics, is reported. Based upon the experiments and phase-field modeling, the enhanced piezoelectricity is explained in terms of the quenching-induced rhombohedral phase formation. These findings will have tremendous impact on development of high performance off-resonance and on-resonance piezoelectric devices with high stability.

Extremely large strain response under low driving electric fields in lead-based textured piezoelectric ceramics

The large strain response and low strain hysteresis of piezoelectric ceramics under low driving electric fields have been eagerly anticipated for actuators applications. However, it remains challenge to simultaneously achieve both of the above properties under low driving electric fields for piezoelectric ceramics. In this work, composition design and texture technique were integrated to develop 1%Sm-doped Pb(Mg1/3Nb2/3)O3–30PbTiO3 (Sm-PMN-PT) textured ceramics to address this challenge. We demonstrate Sm-PMN-PT textured ceramics with highly [001]c orientation exhibit ultrahigh strain response and the lower strain hysteresis under low driving electric fields. At 2 kV/mm, a large strain value of 0.27% and a low hysteresis of 15% were acquired. In addition, the microstructure and crystal structure of Sm-PMN-PT textured ceramics and its random counterpart were studied as well as their electrical properties. This research results provide a new promising candidate materials for developing high-performance piezoelectric actuators with low driving electric fields.

A design for preparation of textured piezoelectric ceramics based on the phase-field simulation

To solve the problem of directional arrangement of small template particles, we designed a lamination technique for the preparation of dense ceramics with high texture degree based on the phase-field simulation. Referring to the experimental data, the initial microstructures of the template and matrix layers were constructed. The effect of the average length of template on the coarsening behavior of the template layer was investigated in detail. The results suggested that there was a stable stage in the growth process of template grains, which would be conducive to the densification of textured ceramics. This phenomenon has been confirmed by corresponding experiments. In addition, we demonstrated a critical thickness of matrix layer for the preparation of highly textured ceramics by using the template with various average lengths. The grain size of highly textured ceramics could be controlled by adjusting the template size and thickness of matrix layer.

Microstructural design of textured KSr2Nb5O15 ceramics by a phase‐field simulation and lamination technique

AbstractThe densification of textured ceramics requires a small template size. However, it is challenging to complete the directional arrangement into the matrix by small templates during the templated grain growth. We propose a strategy to increase the density and texture degree of KSr2Nb5O15 ceramics. The microstructures can be designed by a phase‐field simulation and lamination technique. For the textured KSr2Nb5O15 ceramics, a high piezoelectricity of d33 = 98 pC/N (the highest reported d33 is 65 pC/N) is achieved by the microstructural control. This study provides a novel technique for preparation of textured piezoelectric ceramics with high performances.

Near-ideal electromechanical coupling in textured piezoelectric ceramics

Electromechanical coupling factor, k, of piezoelectric materials determines the conversion efficiency of mechanical to electrical energy or electrical to mechanical energy. Here, we provide an fundamental approach to design piezoelectric materials that provide near-ideal magnitude of k, via exploiting the electrocrystalline anisotropy through fabrication of grain-oriented or textured ceramics. Coupled phase field simulation and experimental investigation on <001> textured Pb(Mg1/3Nb2/3)O3-Pb(Zr,Ti)O3 ceramics illustrate that k can reach same magnitude as that for a single crystal, far beyond the average value of traditional ceramics. To provide atomistic-scale understanding of our approach, we employ a theoretical model to determine the physical origin of k in perovskite ferroelectrics and find that strong covalent bonding between B-site cation and oxygen via d-p hybridization contributes most towards the magnitude of k. This demonstration of near-ideal k value in textured ceramics will have tremendous impact on design of ultra-wide bandwidth, high efficiency, high power density, and high stability piezoelectric devices.

Polarization Fatigue Mechanism of High-Power Textured Piezoelectric Ceramics

Polarization Fatigue Mechanism of High-Power Textured Piezoelectric Ceramics

Achieving both high electromechanical properties and temperature stability in textured PMN‐PT ceramics

AbstractTextured piezoelectric ceramics, such as textured Pb(Mg1/3Nb2/3)O3‐PbTiO3 (PMN‐PT) ceramics, have attracted considerable attention from both academia and industry, as they possess crystal‐like piezoelectric properties, high composition homogeneity, and low manufacturing cost. However, the main difficulty with the textured piezoelectric ceramics is the presence of BaTiO3 (BT) templates, which greatly reduces their piezoelectricity and phase transition temperature. Thus, it is highly recommended to fabricate textured piezoelectric ceramics using as few templates as possible. Here, we successfully fabricated high‐quality &lt;001&gt;‐textured PMN‐28PT ceramics (texturing degree of 99%) by using an extremely small amount of BT templates (1 vol.%) with the help of CuO/B2O3 sintering aids. The textured PMN‐28PT ceramic exhibits 80% piezoelectric coefficient (d33 ∼ 1200 pC/N), 96% electromechanical coefficient (k33 ∼ 88%) and the same temperature stability (Trt ∼ 100, Tc ∼ 150°C) when compared to its single crystal counterpart. In addition, by using an alternating current electric field poling (AC‐poling), the piezoelectric coefficient d33 and dielectric permittivity ε33 of the textured PMN‐28PT ceramics were further enhanced around 5–8%. It is believed that the advantages of high electromechanical properties, low cost, and easy mass production of textured PMN‐28PT ceramic will make it a promising candidate for advanced electromechanical devices.

Manufacturing and uniformity of grain textured piezoelectric ceramics

Manufacturing and uniformity of grain textured piezoelectric ceramics

Direct writing of textured ceramics using anisotropic nozzles

Direct writing is a unique means to align anisotropic particles for the fabrication of textured ceramics by templated grain growth (TGG). We show that alignment of tabular barium titanate (BT) template particles (20–40 μm width and 0.5–2 μm thickness) in a PIN-PMN-PT matrix powder (d50 = 280 nm) is significantly improved during direct writing using anisotropic nozzles at high printing rates. The particle orientation distribution in as-printed filaments, and the texture orientation distribution in sintered ceramic filaments are shown to directly correlate with COMSOL Multiphysics-predicted torque distributions for direct writing with aspect ratio 2, 3 and 5 oval nozzles. Electromechanical strain properties of the textured piezoelectric ceramics significantly improved relative to random ceramics when printed with anisotropic nozzles. Simulations of aspect ratio 20 nozzles and nozzles with interior baffles demonstrate significantly increased torque and near elimination of constant shear stress cores (i.e. plug flow).

Microstructure evolution and reaction mechanism of Pb(Zr1/2Ti1/2)O3-Pb(Zn1/3Nb2/3)O3–Pb(Ni1/3Nb2/3)O3 piezoelectric ceramics with plate-like PbTiO3 template

0.83 Pb(Zr1/2Ti1/2)O3-0.11Pb(Zn1/3Nb2/3)O3-0.06Pb(Ni1/3Nb2/3)O3 (PZNNT) samples with plate-like PbTiO3 (PT) template were prepared using tape casting technology. The microstructure evolution and reaction mechanism between the matrix and PT template was investigated systematically. The quench heat treatment experiment was designed and the microstructure was evaluated. The results showed that the plate-like PT template has relatively low thermal stability which would decompose to form Pb-rich liquid phase and Ti-rich region at the sintering temperature of 900 °C–1050 °C. Plate-like PT template reacted with the PZNNT matrix materials during the sintering process, which did not contribute to the grain growth orientation for PZNNT matrix. Finally, the mechanism of grain growth for the PZNNT ceramics with plate-like PT template is clarified. This work demonstrated that the thermal stability of plate-like template is one of the key factors for fabricating textured piezoelectric ceramics.

High power evaluation of textured piezoelectric ceramics for SONAR projectors

Textured Ceramics of the relaxor ferroelectric PMNT have shown exceptional piezoelectric properties suitable for high power SONAR projectors. The piezoelectric coefficient (d33&amp;gt;800pm/V), the electromechanical coupling coefficient (k33&amp;gt;0.80), and the mechanical quality factor (Qm&amp;gt;90) in various forms of PMNT showcase the potential for these textured ceramics to be implemented in a high power, broad bandwidth acoustic projector. This work attempted to devise a set of experiments to quickly characterize the electromechanical performance of these materials in relevant devices in order to provide feedback to both the material developers and the user community. In this effort, textured PMNT and Manganese doped PMNT (Mn:PMNT) were compared to the performance of conventional lead zirconate titanate (PZT) ceramics. Linearity and harmonic distortion measurements were made in a high pressure test facility to measure source levels of these SONAR projectors. In addition, isothermal measurements were made at 50 degrees Celsius to monitor source levels as a function of duty cycle. The results from these measurements were then compared to modeled results and appropriate recommendations on material composition improvements were made.

Progress on the fabrication of lead-free textured piezoelectric ceramics: perspectives over 25 years

Further enhancement of the piezoelectric response in lead-free piezoelectric ceramics can be accomplished by inducing preferred orientation. In this paper, attempts have been made to review the progress on the fabrication of lead-free textured piezoelectric ceramics by the (reaction) templated grain growth method. The preparation (molten salt synthesis) and alignment (tape casting and extrusion molding) of anisometric template particles were introduced in detail. The texture evolution with heating was visualized by computer simulation. The review of lead-free textured piezoelectric ceramics focused on four promising systems: Na0.5Bi0.5TiO3-based, K0.5Na0.5NbO3-based, Ba(Zr0.2Ti0.8)O3–(Ba0.7Ca0.3)TiO3 and KSr2Nb5O15. It is suggested that texturing of lead-free morphotropic phase boundary compositions will be required in order to realize viable lead-free alternatives to current lead-based materials.

Templated Grain Growth of Textured Piezoelectric Ceramics

ABSTRACT Crystallographic texturing of polycrystalline ferroelectric ceramics offers a means of achieving significant enhancements in the piezoelectric response. Templated grain growth (TGG) enables the fabrication of textured ceramics with single crystal-like properties, as well as single crystals. In TGG, nucleation and growth of the desired crystal on aligned single crystal template particles results in an increased fraction of oriented material with heating. To facilitate alignment during forming, template particles must be anisometric in shape. To serve as the preferred sites for epitaxy and subsequent oriented growth of the matrix, the template particles need to be single crystal and chemically stable up to the growth temperature. Besides templating the growth process, the template particles may also serve as seed sites for phase formation of a reactive matrix. This process, referred to as Reactive TGG (RTGG), has been used to obtain highly oriented Pb(Mg1/3Nb2/3)O3-PbTiO3, Sr0.53Ba0.47Nb2O6, and (Na1/2Bi1/2)TiO3-BaTiO3. Highly oriented Bi4Ti3O12, Sr2Nb2O7, CaBi4Ti4O15, Pb(Mg1/3Nb2/3)O3-PbTiO3, Sr0.53Ba0.47Nb2O6 and (Na1/2Bi1/2)TiO3-BaTiO3 ceramics have been produced by TGG. The resulting ceramics show texture levels up to 90%, and significant enhancements in the piezoelectric properties relative to randomly oriented ceramics with comparable densities. For example, piezoelectric coefficients of textured piezoelectrics are from 2 to 3 times higher than polycrystalline ceramics and as high as 90% of the single crystal values. In textured PMN-PT, a low field (< 5 kV/cm) piezoelectric coefficient (d 33) of ∼1600 pC/N was obtained with > 0.3% strain (at 50 kV/cm). The high field dielectric and electromechanical properties of textured perovskites are more hysteretic than those of single crystals, probably as a result of clamping by the residual template particles, residual random grains, the presence of non-ferroelectric second phases, and a wide orientation distribution. Lateral clamping of one grain by another may also be an important factor in fiber-textured samples. Means to further improve the quality of texture and thus properties of textured piezoelectric ceramics by TGG are presented.

Development of a Templated Grain Growth System for Texturing Piezoelectric Ceramics

High strain actuation can be obtained from crystallographically textured piezoelectric ceramics. Single crystal piezoelectrics demonstrate high strain because crystal orientation can be controlled - the perfect lattice simplifies crystal orientation. Single crystals actuate better than typical ceramics, but are expensive. Highly textured ceramics offer an alternative path to easily aligned crystals. The crystallites in textured ceramics are crystallographically oriented. Textured ceramics are expected to provide improved properties, with lower processing costs. NexTech Materials is developing textured piezoelectrics via Templated Grain Growth. In this process, anisotropic template particles are oriented in a fine matrix. During heat treatment, the templates grow, resulting in a textured polycrystal.