Piezoelectric Strain Coefficient D33 Research Articles

Piezoelectric and dielectric characterization of corona and contact poled PZT-epoxy-MWCNT bulk composites

Three-phase lead zirconate titanate (PZT, PbZr0.52Ti0.48O3)-epoxy-multi-walled carbon nanotube (MWCNT) bulk composites were prepared, where the volume fraction of PZT was held constant at 30%, while the volume fraction of the MWCNTs was varied from 1.0%–10%. The samples were poled using either a parallel plate contact or contactless (corona) poling technique. The piezoelectric strain coefficient (d33), dielectric constant (ε), and dielectric loss tangent (tan δ) of the samples were measured at 110 Hz, and compared as a function of poling technique and volume fraction of MWCNTs. The highest values for dielectric constant and piezoelectric strain coefficients were 465.82 and 18.87 pC/N for MWCNT volume fractions of 10% and 6%, respectively. These values were obtained for samples that were poled using the corona contactless method. The impedance and dielectric spectra of the composites were recorded over a frequency range of 100 Hz–20 MHz. The impedance values observed for parallel-plate contact poled samples are higher than that of corona poled composites. The fractured surface morphology and distribution of the PZT particles and MWCNTs were observed with the aid of electron dispersion spectroscopy and a scanning electron microscope. The surface morphology of the MWCNTs was observed with the aid of a field emission transmission electron microscope.

Vibrational energy-harvesting performance of bio-sourced flexible polyamide 11/layered silicate nanocomposite films

ABSTRACTThe energy-harvesting efficiency of melt processed polyamide 11 (PA11) films and its nanocomposites have been investigated as a function of filler type and content. In the present work, nanoclays have been used as structural modifiers in a PA11 matrix. The nanocomposites were prepared using layered clays, Cloisite 20A, 10A, and Na+, by extrusion process through varying the filler content, 1, 2, 4, and 5 wt.%. The crystalline structure of these nanocomposites has been studied by X-ray diffractometer. It has been demonstrated that layered silicates are not significant for the structural quality of the obtained nanocomposites. Regarding the interlayer peak of different clays, it has also been revealed that Cloisite 20A is partially exfoliated, whereas 10A and Na+ are totally exfoliated in the PA11 matrix. From mechanical and dynamic mechanical analyses, it was found that the addition of layered silicates results in an increase in mechanical properties. The piezoelectric strain coefficient d33 and dielectric constant εR have been measured on polarized films at ambient temperature. Among all the prepared nanocomposites only Cloisite Na+-loaded PA11 nanocomposites showed the best piezoelectric constant. This observation showed that piezoelectric constant not only depends on the crystalline phases but also on the nature of the filler. Cloisite Na+ is more polar than other modified clays and high polarity leads to a better polarization response. A specific method for the quantification of energy vibration recovery has been developed for these nanocomposites. The capabilities of vibrational energy recovery were studied on PA11 loaded with Cloisite Na+.

Effects of fiber volume fraction on strain of piezoelectric fiber composites

Abstract Piezoceramic fibers as the active deforming component in piezoelectric fiber composites have the largest influence on the overall strain of the composites. The results of this study show that the fabricated composites exhibited clearly anisotropic actuation properties. The free strain of piezoelectric fiber composites with 70 % by volume fibers in the longitudinal direction was 2.9 times of that in the transverse direction at the excitation voltage of 2 000 V and excitation frequency of 0.1 Hz. Larger fiber volume fraction can increase the free strain of the composites, e. g. in this case the free strain increased by about 24.6 % and 33.6 % in the longitudinal and transverse directions, respectively, as the fiber volume fraction increased from 70 % to 78 %. The piezoelectric strain coefficient d 33 of piezoelectric fiber composites exhibits nonlinear dependency on the actuation voltage and linear dependency on the logarithm of frequency.

Significance of Micro and Nano PZT Particles on Dielectric and Piezoelectric Properties of PZT-PVDF Composites

PZT-PVDF composites were prepared using different particle size of PZT and a hot press apparatus has been used for making samples. The structural and compositional analysis of the composite sample was done by using Scanning Electron Microscope (SEM) and Energy Dispersive Analysis of X-rays (EDAX) respectively. The grain size of the ball milled PZT powder was analyzed using powder X-Ray Diffraction (XRD). The samples were poled at a fixed temperature for about an hour under different poling fields. The dielectric constant (?r) and the piezoelectric properties like piezoelectric strain coefficient (d33) and voltage coefficient (g33) of composite have been analyzed.

Piezo, ferro and dielectric properties of ceramic-polymer composites of 0-3 connectivity

ABSTRACTFerroelectric PZT-PVDF composites (0–3 connectivity) of specific dimensions were made utilizing a hot press technique. Linear variation in the experimental density of the pellets made from 0.1 to 0.8 PZT volume fraction was observed. The surface morphology of the composite has been micro-graphed using SEM. The variation of the dielectric properties of the composites on PZT volume fractions is reported and analyzed. It is observed that there was an increment in dielectric constant (ϵr) with an increase in temperature and volume fractions. The piezoelectric strain coefficient (d33) increases with an increase in the volume fraction and voltage coefficient (g33) were calculated. Comparisons were made with the Furukawa model to ϵr and d33. The remnant polarization and coercive field were analyzed from the hysteresis plots.

Effects and Mechanism of Combinational Chemical Agents on Solution‐Derived K0.5Na0.5NbO3 Piezoelectric Thin Films

Sodium potassium niobate (KNN) piezoelectric ceramic thin films were prepared by a chemical solution deposition method, in which the introduction of appropriately combinational organic stabilizing agents, including monoethanolamine (MEA), diethanolamine (DEA), and ethylenediaminetetraacetic acid (EDTA), dramatically suppressed the volatile loss of the alkali ions, improved the crystallinity, and promoted crystal orientation of the perovskite phase in the resulting KNN thin films. Theoretical analyses including ab initio calculation based on molecular model indicated that stronger binding structure could form comprising the alkali ions and the combinational EDTA‐(DEA‐MEA) chemical agents than the cases of using individual binding agents separately. Outstandingly large effective piezoelectric strain coefficient d33 under the substrate clamping condition was achieved. The theoretical and experimental results provide the insight on the underlying interaction mechanism between the multiple stabilizing chemical agents and metal ions, and the guidance for establishing the methodology for producing high quality oxide thin films from chemical solutions with dedicatedly designed combinational stabilizing agents.

Ferroelectric behavior and polarization mechanism in odd‐odd polyamide 11,11

ABSTRACTFerroelectric and piezoelectric behavior in odd‐odd polyamide 11,11 are successfully detected for the first time. The maximum coercive field (Ec) of 90 MV/m, and a remnant polarization (Pr) of 40 mC/m2 are obtained at room temperature. A piezoelectric strain coefficient (d33) value as high as −3.9 pC/N has been found in stretched polyamide 11,11 film. The structural change of samples before and after poling is investigated by wide‐angle X‐ray diffraction patterns, differential scanning calorimetry, and Fourier transform infrared spectroscopy. The results indicate that the nature of the ferroelectricity originates from amide group dipoles in the γ‐form crystal regions. Hysteresis behavior appears to result from the crystallites reversal mechanism. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 1094–1099

PMN-PT based quaternary piezoceramics with enhanced piezoelectricity and temperature stability

The phase structure, piezoelectric, dielectric, and ferroelectric properties of (0.80 − x)PMN-0.10PFN-0.10PZ-xPT were investigated systematically. The morphotropic phase boundary (MPB) was confirmed to be 0.30 < x < 0.34. Both MPB compositions of x = 0.32 and x = 0.33 exhibit high piezoelectric coefficients d33 = 640 pC/N and 580 pC/N, electromechanical couplings kp of 0.53 and 0.52, respectively. Of particular importance is that the composition with x = 0.33 was found to process high field-induced piezoelectric strain coefficient d33* of 680 pm/V, exhibiting a minimal temperature-dependent behavior, being less than 8% in the temperature range of 25–165 °C, which can be further confirmed by d31, with a variation of less than 9%. The temperature-insensitive d33* values can be explained by the counterbalance of the ascending dielectric permittivity and descending polarization with increasing temperature. These features make the PMN-PT based quaternary MPB compositions promising for actuator applications demanding high temperature stability.

Effects of sintering behavior on piezoelectric properties of porous PZT ceramics

Porous lead zirconate titanate (PZT) ceramics were fabricated by the gel-casting process of particle-stabilized wet foams and sintered at different temperatures. The bulk density and grain size of porous PZT ceramics increased with the increase of sintering temperature from 1150 to 1250 °C, which exerted remarkable influence on the value of relative permittivity (εr) and piezoelectric strain coefficient (d31 and d33). The relationship between microstructure and electric properties was explained by the space-charge theory reasonably. Under the joint effects of bulk density and grain size, the value of dh and gh decreased with the increase of sintering temperature, resulting in the decrease of hydrostatic figure of merit (HFOM) values from 12633 to 3427×10–15 Pa−1.

PIN-PMN-PT Single-Crystal-Based 1–3 Piezoelectric Composites for Ultrasonic Transducer Applications

In this work, Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) single crystal/epoxy 1–3 composites with different thicknesses (400 μm to 825 μm) were fabricated using the conventional dice-and-fill method. Their properties were compared with the corresponding lead zirconate titanate (PZT) ceramic 1–3 composites. Excellent properties for ultrasonic transducer applications have been achieved, such as high electromechanical coupling coefficient (kt ≈ 78% to 83%), high piezoelectric strain coefficient (d33 ≈ 1000 pm/V), and lower acoustic impedance (Z ≈ 20 Mrayl). The strain levels of PIN-PMN-PT composites were almost constant (1000 pm/V) with decreasing thickness, being much higher than those of PZT composites (650 pm/V). However, an increase in strain hysteresis was observed with decreasing thickness, reaching 25.3% for the 400-μm single-crystal 1–3 composite, which is lower than the corresponding PZT composites (44.1% for 350-μm PZT ceramic 1–3 composite). These results show that PIN-PMN-PT single-crystal 1–3 composites have great potential for use in advanced ultrasound transducer applications.

Processing and Properties of Porous PZT Ceramics from Particle‐Stabilized Foams via Gel Casting

In the present work, porous lead zirconate titanate (PZT) ceramics with porosity ranging from 27.8% to 72.4% were fabricated by the gel‐casting process of particle‐stabilized wet foams with the initial solid loading of 10–30 vol%. The phase, the microstructure, the dielectric property, and the piezoelectric property were characterized. The relative permittivity (εr) and longitudinal piezoelectric strain coefficient (d33) of the investigated samples decreased with increasing porosity. Both the values of hydrostatic strain coefficient (dh) and hydrostatic voltage coefficient (gh) increased moderately with the increase in porosity, which was beneficial for enhancing the value of hydrostatic figure of merit (HFOM). As a result, the prepared sample possessed a maximal HFOM value of 15236 × 10−15 Pa−1 with the porosity of 72.4%. The acoustic impedance (Z) of specimens decreased linearly with increasing porosity, and had the lowest value of 1.95 MRayls, making them promising candidates for application of medical ultrasonic imaging or underwater sonar detectors.

Temperature dependence of dielectric polarization and strain behaviors for rhombohedral PIMNT single crystal with different crystallographic orientations

In this study, the dielectric, ferroelectric and strain behaviors of 0.35Pb(In1/2Nb1/2)O3–0.35Pb(Mg1/3Nb2/3)O3–0.30PbTiO3 (0.35PIN–0.35PMN–0.30PT or PIMNT35/35/30) single crystal with different crystallographic orientations were investigated as a function of temperature. The Curie temperature TC and rhombohedral to tetragonal phase transition temperature Trt were risen up to 188°C and 120°C, respectively. The coercive field EC and remnant polarization Pr for 〈001〉 and 〈110〉 oriented crystals were found to be 5.8kV/cm, 27.5μC/cm2 and 8.5kV/cm, 38.7μC/cm2 at room temperature, respectively. The polarization data were obtained from the hysteresis loops of the crystal measured in a wide temperature range. The unipolar strain level was found to be 0.65% at an electric field of 32kV/cm, with piezoelectric strain coefficient d33∼2000 pC/N for 〈001〉 oriented crystal. Besides, the intermediate metastable state was induced at an electric field of 12.5kV/cm for 〈110〉 oriented crystal, which can be utilized in large power transducers such as sonar and actuator.

Self‐Bias Response of Lead‐Free (1−x)[0.948 K0.5Na0.5NbO3–0.052 LiSbO3]–xNi0.8Zn0.2Fe2O4–Nickel Magnetoelectric Laminate Composites

This study reports the magnetoelectric (ME) response of lead‐free particulate composites given as (1−x)[0.948 K0.5Na0.5NbO3–0.052 LiSbO3]–xNi0.8Zn0.2Fe2O4 (KNNLS–NZF) and bimorph laminates given as KNNLS–NZF/Ni/KNNLS–NZF. The particulate ME composites were found to exhibit island–matrix microstructure as confirmed by scanning electron microscopy and elemental mapping. Detailed investigations were conducted on optimization of the magnitude of magnetic and piezoelectric properties by varying the sintering condition and NZF mole fraction. It was found that longitudinal piezoelectric strain coefficient d33 and electromechanical coupling factor kp decreased with increasing NZF concentration. On the other hand, the magnitude of saturation magnetization Ms, remnant magnetization Mr, magnetic permeability μ, and magnetostriction λ was found to increase with increasing NZF fraction. The composition 0.7 KNNLS–0.3 NZF sintered at 1060°C was found to exhibit d33 of 73 pC/N, Ms of 19 emu/g, and maximum ME coefficient αE of 20.14 mV/cm·Oe under Hac=1 Oe at 1 kHz. The bimorph laminates were fabricated by embedding Ni plate between (1−x)KNNLS–xNZF disks with varying electrical connections to achieve radial and bending modes. The radial mode laminates were found to exhibit typical ME response without any self‐bias effect with maximum αE of 261.3 mV/cm·Oe and high DC magnetic field sensitivity of 1 μT at 1 kHz. The bending mode laminates were found to exhibit self‐biased ME response whose magnitude and shape was dependent upon the NZF concentration.

Effects of Size of Spray‐Dried PZT Powder and Dipole Density of Polymer Matrix on the Electrical Properties of PZT/Odd–Odd Nylons 0–3 Composites

A series of 0–3 composites of lead zirconate titanate (PZT)/ferroelectric odd–odd nylons was prepared with variations in the size of PZT powder and in the dipole density of ferroelectric odd–odd nylons. The as‐formed PZT powder prepared by a spray‐drying technique consists of spherical granules composed of large numbers of interconnected fine particles. Electrical properties of the composites as a function of the size of this particular PZT powder and the dipole density of ferroelectric odd–odd nylons were studied. With the PZT powder sintered at 1100°C, the relative permittivity, polarization, and piezoelectric strain coefficient (d33) of the PZT/nylon composites increased with increasing powder size of PZT. The electrical properties of the composites also increased as the dipole density of the polymer increased. The PZT/nylon 57 composite exhibited a high‐relative permittivity and piezoelectric strain coefficient d33 due to an increase in its dipole density. The optimum relative permittivity and polarization of this composite were obtained by the PZT with an average granule size of 95 μm. The highest piezoelectric strain coefficient d33 of the 0–3 composite was found at 28 pC/N whereas the relative permittivity was approximately 73.

PIEZOELECTRIC COEFFICIENT PROPERTIES OF A FLEXIBLE PZT/UPE/C COMPOSITE

A flexible piezoelectric composite, made from Lead Zirconate Titanate(PZT) powder and Unsaturated polyester (UPE) resin, was doped with small amount of carbon semiconductor powder. The piezoelectric strain coefficient (d33) and the dielectric behavior have been studied for this ceramic/polymer composite. The dielectric constant processes of the composite were observed to be dominated by those of undoped ceramic- polymer. The practical results of PZT/UPE/C with ratio 49/50/1 adding a semiconductor phase in the composite showed piezoelectric strain coefficient can be controlled and a continuous electric flux path could be created between the PZT grains. This composite may be poled at low voltage and in shorter time compared with composites without a conductive phase.

Lead-free piezoelectric (K0.5Na0.5)NbO3 thin films derived from chemical solution modified with stabilizing agents

( K 0.5 Na 0.5 ) NbO 3 (KNN)-based ferroelectric thin films were prepared by a chemical solution approach modified with both diethanolamine (DEA) and ethylenediaminetetraacetic acid (EDTA) as the stabilizing agents. The obtained KNN thin films exhibited a remarkably low leakage current and well-saturated polarization hysteresis loop. The effective piezoelectric strain coefficient d33 and voltage coefficient g33 under the clamping of the substrate were improved to 74.0 pm/V and 28.3 mm V/N, respectively. The reason for the superior properties was found that the addition of EDTA and DEA was effective in suppressing the volatilization of K and Na at moderate temperature before the crystallization.

Lead-free (K0.5Na0.5)0.95(LiSb)0.05Nb0.95O3-BaTiO3 piezoceramics

Lead-free (1-x)(K0.5Na0.5)0.95(LiSb)0.05Nb0.95O3-xBaTiO3 (abbreviated as (1-x)KNNLS-xBT) piezoceramics were synthesized by conventional solid state sintering and the effect of BaTiO3 on the microstructure, dielectric and piezoelectric properties was investigated. It was found that both orthorhombic-tetragonal (T O-T) and tetragonal-cubic (T C) phase transition temperatures decreased obviously with increasing BaTiO3 content. Although proper amount of BaTiO3 facilitated the sintering of (1-x)KNNLS-xBT ceramics, the addition of BaTiO3 affected the relaxor behavior slightly and it was not beneficial to improve piezoelectric strain coefficient d 33, remnant polarization P r and piezoelectric coupling constant k p.

A series of 0‐3 composites of lead zirconate titanate and ferroelectric nylon77: Preparation and electrical properties

AbstractA series of 0‐3 composites of lead zirconate titanate (PZT) and nylon77 was prepared with PZT volume fractions between 0.1 and 0.6 using the combined method of solvent casting and hot pressing. Depending upon the volume fraction of PZT, the relative permittivities of the composites were found to be in the range of 200–2000 when measured at the highest practically possible temperature of 200°C. As PZT volume fraction increases, both the relative permittivity and the piezoelectric constant d33 increase. The best combination of electrical properties and flexibility was obtained in 0.5 PZT volume fraction composites. At this composition, the remanent polarization Pr of composites was up to 1000 mC/m2 at the applied electric field of 40 MV/m and it increased with an increase in temperature. The highest piezoelectric strain coefficient d33 was obtained at 17 pC/N in 0.6 PZT volume fraction composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Homogenization of textured as well as randomly oriented ferroelectric polycrystals

Abstract Microstructural features such as spatial correlation of crystallographic orientations and morphological texture in piezoelectric polycrystals is modeled computationally. The mathematical homogenization of piezoelectric material is implemented using the finite element method (FEM) by solving the coupled equilibrium electrical and mechanical fields. A three-dimensional (3D) FEM model is adapted to polycrystalline medium. The dependence of macroscopic electromechanical properties on domain orientation and texture of single-crystalline as well as polycrystalline ferroelectric BaTiO3 and PbTiO3 are demonstrated based on this model. The homogenized piezoelectric moduli of the polycrystals and single-crystals of these materials exhibit remarkable but contrasting behaviors. The aggregate texture for polycrystalline ferroelectrics is assumed to have a Gaussian (normal) distribution. The longitudinal piezoelectric strain coefficient d33 assumes a higher value than the corresponding single-crystalline value of BaTiO3 at a distribution characterized by σ between 0.5 and 0.7 However, for PbTiO3 the maximum is shown at the perfect {0 0 1} texture. Therefore, polycrystalline materials are expected to be improved in their global piezoelectric performance by engineering the texture of the microstructure.

Piezoelectric properties of (Li, Sb, Ta) modified (Na,K)NbO3 lead-free ceramics

Lead-free alkaline niobate based (Na0.52K0.48−xLix)Nb1−x−ySbxTayO3 piezoceramics have been prepared by the conventional mixed oxide method without using other techniques. An experimental formula for producing a set of ceramics with high piezoelectric properties is obtained while cutting down the Ta content and maintaining a high Curie temperature. The highest piezoelectric constant d33 is 308pC∕N, with a dielectric loss tanδ of about 2.0% and a Curie temperature of 339°C. The samples also possess outstanding high-field piezoelectric strain effects. The high-field piezoelectric strain coefficient d33* is as high as 490pm∕V. (Li, Sb, Ta) modified (Na,K)NbO3 shifts the orthorhombic to tetragonal phase transition to near room temperature, which plays an important role in the improvement of the piezoelectric properties.