Piezoelectric Charge Constant Research Articles

Investigation of the structural and piezoelectric characteristics of (1-x)Pb(Zr, Ti)O3-xPb(Zn0.4Ni0.6)1/3Nb2/3O3 ceramics with R-PC-T multistructure

The structural and various electrical properties of (1-x)Pb(Zr1-zTiz)O3-xPb(Zn0.4Ni0.6)1/3Nb2/3O3 [(1-x)P(Z1-zTz)-xPZNN] piezoceramics have been systematically investigated to ascertain the compositions that manifest a rhombohedral-pseudocubic-tetragonal (R-PC-T) multistructure. Rietveld refinement results indicate that the pseudocubic (PC) structure observed in the (1-x)P(Z1-zTz)-xPZNN piezoceramics closely resembles the Pm3m cubic structure. Nonetheless, the PC structure cannot be classified as cubic, given that piezoceramics exhibiting the PC structure also demonstrate ferroelectric and piezoelectric properties. The R-PC-T multistructure was detected in (1-x)P(Z1-zTz)-xPZNN piezoceramics for compositions where 0.335 ≤ x ≤ 0.44, across various z values. Compositions exhibiting the R-PC-T multistructure are identified as particularly promising. Notably, the piezoceramic with the composition 0.58 P(Z0.41T0.59)-0.42PZNN (x = 0.42 and z = 0.59) displayed remarkable piezoelectric properties, including a high piezoelectric charge constant, d33, of 825 pC/N, a coupling coefficient, kp, of 0.7, and a strain of 0.185% at 3.0 kV/mm, alongside a high Curie temperature (TC) of 240 °C.

Tuning the Piezoelectric Performance of K0.5Na0.5NbO3 through Li Doping: Insights from Structural, Elastic and Electronic Analyses.

The structural, elastic, piezoelectric, and electronic properties of Li-doped K0.5Na0.5NbO3 (K0.5-xNa0.5-yLix+yNbO3, KNN-L) are calculated. The properties of KNN-L are related to the Li-doping content and the replaced K or Na atoms. The bulk modulus, the shear modulus, and Young's modulus of KNN-L are mostly higher than those of KNN, and the hardness value increases. The Poisson ratio of KNN-L is lower than that of most KNN, and the ductility is reduced. All doped structures are direct band gap semiconductors. K0.5Na0.375Li0.125NbO3 has the largest piezoelectric charge constant, d33 = 44.72 pC/N, in the respective structures, which is 1.5 fold that of K0.5Na0.5NbO3 (29.15 pC/N). The excellent piezoelectric performance of Li-doping KNN-L was analyzed from the insights of elastic and electronic properties.

Enhanced soft piezoelectric properties of Sb2O3 doped 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 materials

In this paper, we have studied the soft piezoelectric properties of 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 doped with Sb2O3. The optimal piezoelectric charge constant and dielectric permittivity of the calcined and sintered 0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3 were determined by varying the Sb2O3 content. The mol% of Sb2O3 was set to 0, 0.05, 0.1, 0.15, and 0.2, and the doped ceramics were sintered at a temperature of 1475 °C. The piezoelectric charge constant d33, electromechanical coupling coefficient kp, and dielectric permittivity εr of the doped ceramics increased with the increasing Sb2O3 content, whereas their Curie temperature Tc slightly decreased. At 0.1 mol% of Sb2O3, the highest piezoelectric charge constant, electromechanical coupling coefficient, and dielectric permittivity values were obtained. Although the Curie temperature was slightly lowered, the dielectric permittivity improved. 0.5BZT-0.5BCT doped with Sb2O3 exhibited a high remnant polarization Pr even when a weak coercive electric field Ec was applied, resulting in an easy polarization. It can be seen that the improved electrical properties and the behavior of the P-E hysteresis loop through the dopant addition of Sb2O3 are close to the soft piezoelectric characteristics. Thus, the synthesized lead-free and Sb2O3-doped ceramics, with excellent piezoelectric properties and depolarization behaviors, are expected to replace lead-based ceramics and will be useful in energy converters, such as piezoelectric transformers.

Parametric estimation analysis of compressive stress effects on piezoelectric properties of PZT ceramic

ABSTRACT In this study, the frequency and capacitance of piezoelectric materials due to compressive stress were analyzed, and the overall material properties (compliance matrix, piezoelectric charge constant and dielectric constant) of piezoelectric ceramics were optimized using parametric estimation methods. The piezoelectric ceramic used for optimization was KICET-PZT8, and the compressive stress was applied from a stress-free condition up to 50 MPa. As a result, with increasing compressive stress, the values of s 11 E , − s 12 E and s 66 E tended to increase, while − s 13 E and s 33 E increased and then decreased at 20 MPa or higher. − d 31 and d 33 showed the maximum values at 40 MPa of compressive stress, with the values reaching 147 pC/N and 375 pC/N, respectively. These values were analyzed to have increased by 117% and 115%, respectively, compared to the stress-free condition. Additionally, the dielectric constant ( ε 33 T ) was found to increase linearly with the applied compressive stress. The understanding of the changes in piezoelectric properties under various compressive stresses derived from this study is expected to be applicable in various ways for the design and application of piezoelectric devices using compressive stresses, including BLT.

Study of temperature and frequency dependant dielectric, impedance, AC resistivity, modulus spectroscopy and electromechanical coupling properties of [BaNd0.1Ti0.8Nb0.1O3](1-x)[Na0.5Bi0.5TiO3]x relaxor ferroelectric ceramics

[BaNd0.1Ti0.8Nb0.1O3](1-x)[Na0.5Bi0.5TiO3]x ceramics with x = 0.25, 0.40, 0.60, 0.65 & 0.70 were prepared through solid-state sintering route. In the present study, temperature and frequency dependant dielectric, Impedance, AC resistivity, modulus spectroscopy and electromechanical coupling properties carried out. These materials showed modulus resonance and anti-resonance i.e. electromechanical coupling (M″ vs. frequency). From these modulus resonance and anti-resonance studies piezoelectric charge constant (d33) was obtained. The values of the piezoelectric charge constant (d33) are 3.34 nm V−1, 6.26 nm V−1, 11.58 nm V−1, 14.10 nm V−1 & 10.70 nm V−1 for x = 0.25, 0.40, 0.60, 0.65 & 0.70, respectively. In the present study, the modulus electromechanical was studied in jig with spring which applies constant stress on the ceramic sample. The higher value of electromechanical coupling conversion in the present study may be attributed to this constant applied stress, higher temperature and polarized oxygen vacancies at the crystal lattice at these elevated temperatures (773 K & 873 K).

Additive Manufacturing of Piezoelectric Niobium-Doped Lead Zirconate Titanate (PZT-N) by Binder Jetting

Binder jetting is an emerging indirect additive manufacturing technique for ceramic materials, which could be employed to produce application-oriented designed components impossible to achieve with traditional processes and featuring enhanced performances. In our study, niobium-doped lead zirconate titanate (PZT-N) powder, usually processed through the standard press-and-sinter route, was employed as the raw material. First, the powder was characterized in terms of granulometry and flowability to assess its suitability for the printing process. Then, shaping by binder jetting was studied, and the effect of three levels of binder saturation (75–90–105%) on the green bodies was assessed. Finally, the microstructure of the sintered samples was studied using SEM, to investigate the effect of thermal treatments on the grain size distribution and residual porosity (~40%). The piezoelectric properties were measured and compared to those of conventionally processed material. The piezoelectric charge and voltage constants (d33 and g33) were evaluated to determine the possible use of printed parts as porous piezoelectric components to be exploited in hydrophones in the direct mode.

A study on Sm2O3-doped Ba(Zr0.02Ti0.98)O3 ceramics for sensor applications

ABSTRACT Ba(Zr0.02Ti0.98)O3 (BZT) samples with various weight percentages of Sm2O3 (0.02–0.06) were synthesized and calcined at 1100°C for 4 h. Circular pellets were prepared using calcined powders and sintered at 1450°C for 2 h. The sintered and poled samples were used for the measurement of various electrical properties. Maximum piezoelectric charge constant (d 33) of 372 pC/N obtained for 0.02 wt.% Sm2O3-doped BZT. Dielectric constant (K = 15,855) at 100 Hz was found maximum for this composition at Curie temperature (T c) of 125°C. Scanning electron microscopy (SEM) study revealed a decrease in grain size with an increase in Sm2O3 content. Largely, a lower concentration of Sm2O3-doped BZT compositions with higher d 33 could be suitable for vibration sensor and accelerometer applications.

3D Printing and processing of miniaturized transducers with near-pristine piezoelectric ceramics for localized cavitation

The performance of ultrasonic transducers is largely determined by the piezoelectric properties and geometries of their active elements. Due to the brittle nature of piezoceramics, existing processing tools for piezoelectric elements only achieve simple geometries, including flat disks, cylinders, cubes and rings. While advances in additive manufacturing give rise to free-form fabrication of piezoceramics, the resultant transducers suffer from high porosity, weak piezoelectric responses, and limited geometrical flexibility. We introduce optimized piezoceramic printing and processing strategies to produce highly responsive piezoelectric microtransducers that operate at ultrasonic frequencies. The 3D printed dense piezoelectric elements achieve high piezoelectric coefficients and complex architectures. The resulting piezoelectric charge constant, d33, and coupling factor, kt, of the 3D printed piezoceramic reach 583 pC/N and 0.57, approaching the properties of pristine ceramics. The integrated printing of transducer packaging materials and 3D printed piezoceramics with microarchitectures create opportunities for miniaturized piezoelectric ultrasound transducers capable of acoustic focusing and localized cavitation within millimeter-sized channels, leading to miniaturized ultrasonic devices that enable a wide range of biomedical applications.

Effect of Contents on the Electrical and Piezoelectric Properties of (1 - x)(Bi, Na)TiO3-x(Ba, Sr)TiO3 Lead-Free Piezoelectric Ceramics.

In this study, the composition of lead-free piezoelectric ceramics (1 - x)(Bi0.5Na0.5)TiO3-x(Ba0.5Sr0.5)TiO3 with excellent piezoelectric properties was investigated. Crystal analysis and electrical and piezoelectric properties were analyzed according to the content of the BST composition. A phase change from rhombohedral to tetragonal structure was observed in 0.12 BST, and the densest and most uniform microstructure was confirmed in this composition. The dielectric constant increased from 905 to 1692 as the composition of BST increased to 0.12 BST. Afterward, as the composition of BST increased, the permittivity tended to decrease. Additionally, at 0.12 BST, Pr was the highest at 23.34 μC/cm2. The piezoelectric charge constant (d33) and the electromechanical coupling coefficient (kp) were 152 pC/N and 0.37, respectively, and showed the highest values at 0.12 BST. Curie temperature (Tm) was analyzed 242 °C at 0.12 BST, the optimal composition. It was confirmed that the characteristics of 0.12 BST were excellent in all conditions. Therefore, it was confirmed that 0.12 BST is the optimal composition for (1 - x)BNT-xBST piezoelectric ceramics.

Two-step simulation of piezoelectric properties of porous PZT according to porosity

ABSTRACT Porous piezoelectric materials have been widely used in hydrophone applications owing to their excellent hydrostatic charge constant (dh) and voltage constant (gh). However, owing to the difficulty in sample manufacturing, the evaluation of the overall piezoelectric properties for reliable device design using simulations is challenging. Herein, a two-step simulation was performed to accurately determine the overall properties of the porous PZT. First, the piezoelectric charge constant was calculated by displacement calculations using the electrostrictive effect. Second, using the calculated piezoelectric charge constant and impedance spectrum obtained from the experiment, the initial value for optimizing the properties was selected, and the overall properties were obtained using the parametric estimation technique. These parametric estimation simulation procedures were performed with the samples of radial and thickness modes based on the IEEE standards. Finally, the piezoelectric properties obtained were compared and verified with the experimental values. Therefore, the overall piezoelectric properties include mechanical, frequency and dielectric properties according to the porosity were obtained with reliable results.

Physical properties of Sm2O3 added Pb(Ni1/3Nb2/3) O3–Pb(Zr0.32Ti0.68)O3 system ceramics for piezoelectric speaker application

In this article, to develop the composition ceramics for the application of single-layer piezoelectric speaker, Pb(Ni1/3Nb2/3)0.5(Zr0.32Ti0.68)0.5O3 co-doped with Ta2O5 and Sm2O3 were manufactured and then their dielectric and piezoelectric properties were investigated. At the 0.4 wt% Ta2O5 and 0.0 wt% Sm2O3 added composition ceramics, excellent physical properties were also appeared, respectively: the dielectric constant (ε r) of 6778, piezoelectric charge constant (d33) of 1027 [pC/N], electromechanical coefficient (k p) of 0.67 and curie temperature of 155 [°C]. These values were suitable for the device application such as ultrasonic tooth cleaner and piezoelectric speakers.

Hammer Impact-Driven Power Generator Using Buzzer-Type Piezoelectric Energy Converter for Wind Power Generator Applications

A novel hammer-impact-driven power generator that uses a buzzer-type piezoelectric energy converter (BPEC) for wind-power-generator applications was designed, and the dynamic motions and output characteristics were analyzed. As the active material, Sm0.025-Pb0.9625[(Mg1/3Nb2/3)0.71Ti0.29]O3 (Sm-PMN-PT)ceramic was used; this material has a high piezoelectric charge constant of 1100 pC/N and an electromechanical coupling factor of 58%. A rotational impeller triggered an impact between one end of the bar-type hammer, and, thereby, impact energy transferred to the BPECs. The manufactured power generator was tested from 50 RPM to 250 RPM, using the handmade evaluation system; it was able to operate with small impact force and greatly improved output performance as rotation speed increased. The maximum output of the generator was 10.4 W at a load resistance of 500 Ω and rotation speed of 250 RPM. For improvement of the output characteristics, the generators were arranged such that they could operate simultaneously. Moreover, the proposed model was applied to a Savonius–Darrieus turbine, and the output performance was evaluated at various wind conditions in a wind tunnel.

Developing a face-shear lead-free piezoelectric transducer through anti-parallel co-poling and its application to an omnidirectional piezoelectric transducer

Face-shear deformation was observed in various square piezoelectric transducers prepared using the anti-parallel co-poling method, which led to uniform polarization and the generation and receipt of pure fundamental shear horizontal (SH0) waves without any Lamb wave. The amplitude of the SH0 wave was found to be proportional to the piezoelectric charge constant (d33) of the piezoceramic, suggesting that the d33 value can be used as a figure of merit for piezoelectric transducers with strong SH0 waves. The amplitude of the SH0 wave associated with the square piezoelectric transducer is large at 0° and 90° but almost zero at 45°; therefore, a piezoelectric transducer with good omnidirectional properties needs to be developed. A ring-type omnidirectional piezoelectric transducer was produced using eight trapezoidal piezoceramics. The minimum amplitude of the SH0 wave generated and received by the ring type-transducer exceeded 70% of the maximum amplitude. Hence, this ring-type transducer is highly omnidirectional and can be used for nondestructive testing and structural health-monitoring applications.

High‐power piezoelectric energy harvester produced using [0 0 1]‐textured (Na, K)NbO3‐based lead‐free piezoceramics

AbstractHigh‐power piezoelectric energy harvesters (PEHs) require piezoceramics with a large kp and d33 but small εT33/ε0 values. The [0 0 1]‐textured 0.96(Na, K)(Nb1−xSbx)–0.04SrZrO3 piezoceramics (x = 0.025 and 0.045) exhibited the improved electromechanical coupling factor (kp) and piezoelectric charge constant (d33); however, the increase of dielectric constant (εT33/ε0) was not significant. Further, the textured piezoceramic with x = 0.045 shows the large d33 × g33 value of 21.5 pm2/N, where g33 is piezoelectric voltage constant, indicating that texturing is a good technique to fabricate the piezoceramics for PEH. The impedance curve of the PEH consisting of the metal substrate and textured piezoceramic shows a piezoelectric resonance peak at a low frequency, which is the same as the mechanical resonance frequency of the PEH. Hence, the PEH can be considered a piezoelectric material. The figure of merit of the PEH was determined using the mechanical quality and electromechanical coupling factor calculated from the impedance curve of the PEH. A large power output of 1.7 mW was obtained from the type‐1 PEH at the resonance frequency produced using the textured thick film (x = 0.045). Hence, this PEH can be used as a permanent power source for microelectronic devices in the Internet of Things.

Dependence of local atomic structure on piezoelectric properties of PbZr1−xTixO3 materials

ABSTRACT Lead zirconate titanate (PZT, ) is a piezoelectric ceramic which can be used for several applications such as actuators, sensors, and microelectronic devices. Depending on its composition, PZT can exhibit rhombohedral, orthorhombic (tetragonal) phases, with the piezoelectric charge constant () key to evaluating its piezoelectric properties. In this study, () was calculated using density functional perturbation theory (DFPT) based on first-principles methods. First, we reveal that the rhombohedral structure is stable for Zr-rich compositions. Second, extending the study to and (PSZT), we evaluated the values of both theoretically and experimentally to investigate how they are affected by doping. The microscopic movements of individual atoms within the optimized crystal were analyzed to investigate the correlations between the structural characteristics and . The results show that the relative positions of Ti and Zr (B-site) atoms and the quadratic elongation in the PZT octahedron depend strongly on the piezoelectric charge constant , which itself depends on the Ti content. The local atomic structural parameters described in this study can be used as a descriptor for the high-throughput screening of PZT materials.

Boosting transduction coefficient in BaTiO3-Based piezoceramic through phase boundary engineering

Transduction coefficient (d33×g33) is the core parameter for evaluating piezoelectric energy harvesting materials. However, due to the thermodynamic constraints, the synergistic variation between piezoelectric charge constant (d33) and dielectric constant (εr) indeed hinder the further increase of d33×g33. Herein, an enhanced d33×g33 of 13,000 × 10−15 m2/N was achieved in 0.80BaTiO3-0.10CaTiO3-0.10BaZrO3 (BC0.1ZT) lead-free solid solution for the first time through a phase boundary engineering strategy. The high d33×g33 mainly stems from non-synergistic variation of dielectric and piezoelectric performance in the rhombohedral-orthorhombic (R-O) phase boundary, in which the low εr comes from the increased domain size and reduced domain wall density; while the high configurational sensitivity of the unique domains to external electric field contributed to the high d33. Our findings provide an alternative approach for enhanced energy harvesting performance by tracing the strategy of designing phase boundary to decouple d33 and εr.

Experimental and simulation studies on dielectric, AC resistivity and electromechanical properties of sodium bismuth titanate based ceramics

The experimental and simulation of dielectric, AC resistivity and dielectric resonance and anti-resonance data on (Na0.5Bi0.5)(NdxTi1-2xNbx)O3] ceramics were carried out using modified Lorentz equations as proposed by us instead of well know and generally applied laws like Arrhenius law and formulas on piezoelectricity to obtain activation energy, relaxation time, piezoelectric charge constant and voltage constant directly from the experimental data. The piezoelectric charge constant (d33) evaluated from the modeling are 864.64 p.m/V and 122.40 p.m/V; whereas the piezoelectric voltage constant (g33) are 10.88 p.m2/C and 8.55 p.m2/C for x = 0.0125 and 0.025 ceramic samples, respectively.

Structural and piezoelectric properties of textured NLKNS‐CZ thick films and their application in planar piezoactuator

Abstract0.97(Na0.5‐xLixK0.5)(Nb0.89Sb0.11)O3‐0.03CaZrO3 [(N0.5‐xLxK)(NS)‐CZ] piezoceramic (x = 0.325) has a pseudocubic‐tetragonal‐orthorhombic (PC‐T‐O) multi‐structure. The PC structure formed in this piezoceramic was identified as the R3m rhombohedral structure. This piezoceramic showed the large piezoelectric charge constant (d33) of 515 pC/N due to the PC‐T‐O multi‐structure. The NaNbO3 (NN) templates were used to texture the (N0.5‐xLxK)(NS)‐CZ thick films along the (001) direction, and the textured thick film (x = 0.0375) had a large Lotgering factor of 95.6%. The PC‐T‐O multi‐structure was observed in this thick film (x = 0.0375), but the thick film (x = 0.0325) showed a PC‐O structure owing to the diffusion of the NN templates into the thick film. The textured thick film (x = 0.0375) exhibited an increased d33 of 625 pC/N because of the PC‐T‐O multi‐structure and the lineup of grains along the [001] direction. A textured thick film (x = 0.0375) was used to fabricate a planar‐type actuator to confirm its applicability to electrical devices. This actuator exhibits large acceleration (580.3 G) and displacement (150 μm) at a low electric field of 0.2 kV/mm with a short response time of 3.0 ms. Therefore, the (N0.5‐xLxK)(NS)‐CZ thick films are excellent lead‐free piezoceramics.

Polymer conformation-dependent piezoelectric properties and self-bias magnetoelectric responses in adhesive-free laminate composites of Ni-foam/PVDF/Ni-foam

In the past decade, polymer-based magnetoelectric (ME) laminate composites have been developed for feasible applications such as flexible energy harvesters and wearable sensors. The 2-2-type ME laminate composites have been typically prepared by epoxy adhesion of piezoelectric and magnetostrictive layers, which is a drawback that disrupts strain transfer from the magnetostrictive phase to the piezoelectric phase due to its strong hardness after epoxy curing. In this study, to overcome the disadvantage of insufficient strain transfer due to the adhesive layers, we designed adhesive-free laminate composites consisting of porous magnetostrictive nickel foam (NF) and soft poly (vinylidene fluoride) (PVDF) films, which exhibited good physical coupling via the sandwich hot-pressing of NF/PVDF/NF. In addition, the self-bias ME effect could be expected from NF, since it exhibits butterfly-shaped magnetostrictive hysteresis loops. Therefore, NF/annealed PVDF(AP)/NF and NF/hot-pressed PVDF(HP)/NF were prepared for investigating the polymer conformation during the fabrication process of ME laminates. Polymer conformation-dependent piezoelectric properties were investigated after annealing and hot-pressing, respectively. The NF/AP/NF laminates (mM/mP = 0.88) were found to exhibit a β/α phase ratio of 2.07, degree of crystallinity (χc) of 46.5%, piezoelectric charge constant (d33) of 17.7 pC/N, and self-bias ME response of 1.88 mV/cm Oe (94% of the maximal ME response at Hbias = 20 Oe). The NF/HP/NF laminates (mM/mP = 1.26) were found to exhibit a β/α phase ratio of 1.40, χc of 32.2%, d33 of 12.4 pC/N, and self-bias ME response of 2.27 mV/cm Oe (92% of the maximal ME response at Hbias = 10 Oe). The high β/α phase ratio were carried out sufficient stretching effect during hot-press laminating process. The optimal piezoelectric properties of β/α phase ratio and χc were induced by predominant stretching of PVDF chains rather than recrystallization during the hot-press. Further, reliable self-bias ME responses were obtained in the adhesive-free laminate composites by enhancement of coupling effect between magnetostrictive and piezoelectric phases. As a result, the sandwich laminate composites of NF/PVDF/NF were successfully prepared via hot-pressing and reliable ME responses were obtained without requiring the electroding process. This demonstrates the feasibility of ME laminate composites for use in wearable energy harvesters or sensors through removal of the hard adhesive layer.

Aligned cellulose nanofiber composite made with electrospinning of cellulose nanofiber - Polyvinyl alcohol and its vibration energy harvesting

This paper reports an aligned cellulose nanofiber (CNF) composite that exhibits flexibility, transparency, and improved mechanical and piezoelectric properties. The aligned CNF composite was made by electrospinning CNF-polyvinyl alcohol (PVA) blend, followed by casting CNF suspension. The CNF-PVA blend was electrospun to form a CNF-PVA fiber mat, and an optimum CNF-PVA ratio and the spinning parameters were determined by examining CNF alignment. Then, the electrospun CNF-PVA mat was coated with CNF suspension to fabricate the aligned CNF composite. The aligned CNF composite was transparent (85.3%) and had a higher orientation index (α = 0.54) than a neat CNF film. Besides, the composite showed improved mechanical properties. In consequence of CNF alignment, the piezoelectric charge constant, d31 of the composite was 14.5 pC/N, which was more than double of the neat CNF film. With this piezoelectric behavior, the composite was applied to a vibration energy harvester (VEH), and it showed an output power of 5.43 nW. All about the piezoelectric and mechanical property improvement were explained in this paper. The aligned CNF composite is flexible, lightweight, environment-friendly, and low-cost.