Piezoelectric Strain Constant D33 Research Articles

Influence of Sb2O3 doping on the properties of KBT-NBT-BT lead-free piezoelectric ceramics

0.144(K0.5Bi0.5)TiO3-0.85(Na0.5Bi0.5)TiO3-0.006BaTiO3 (KBT-NBT-BT) lead-free piezoelectric ceramics were prepared using a conventional solid state method. The influence of Sb2O3 doping on the crystal phase, surface microstructure and properties of the KBT-NBT-BT lead-free piezoelectric ceramics were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM) and other analytical methods. The results show that all compositions are of pure perovskite structure solid states. Sb2O3 doping does not influence the microstructure of KBT-NBT-BT lead-free piezoelectric ceramics obviously in the Sb2O3 doping range of 0.1-0.5 wt.%. Sb2O3 functions as a donor when doped small amount, while functions as a acceptor when doped large amount. The piezoelectric strain constant (d33) increases first and then decreases; the dielectric constant (e(superscript T subscript 33)/e0) and the dielectric loss (tan δ) decrease continuously when the amount of Sb2O3 dopant increases. When the doping amount of Sb2O3 is 0.1 wt.%, the KBT-NBT-BT piezoelectric ceramics with good comprehensive properties are obtained, whose d33, e(superscript T subscript 33)/e0 and tan δ are 147 pC/N, 1510 and 4.2%, respectively.

Influence of La2O3 Doping Amount on Properties of NBT-KBT-BT Lead-Free Piezoelectric Ceramics

0.85(Na0.5Bi0.5)TiO3-0.144(K0.5Bi0.5)TiO3-0.006BaTiO3(NBT-KBT-BT) lead-free piezo -electric ceramics were prepared using conventional solid state method. The influence of La2O3 doping amount on the crystal phase, surface microstructure and properties of the NBT-KBT-BT lead free piezoelectric ceramics were investigated using X-ray diffraction(XRD), Scanning electron microscopy(SEM) and other analytical methods. The results show that La2O3 has diffused into the lattice of NBT-KBT-BT ceramics. Consequently, a pure perovskite phase is formed. SEM images show that the microstructure of the ceramics is changed with the addition of a small amount of La2O3, La2O3 doping can make grain growing. The piezoelectric strain constant(d33) starts increasing and then decreasing, the dielectric constant(εT33/ε0) increases continuously and the dielectric loss(tanδ) starts increasing and then decreasing and then increasing when La2O3 doping amount increases. When the doping amount of La2O3 is 0.4wt.% and the sintering temperature is 1160°C, the NBT-KBT-BT piezoelectric ceramics with good comprehensive properties can be obtained. Its piezoelectric strain constant(d33), dielectric constant(εT33/ε0), and dielectric loss(tanδ) are 151pC/N, 1543 and 4.2%, respectively.

Three-scale analysis of BaTiO3 piezoelectric thin films fabrication process and its experimental validation

A three-scale analysis of crystal growth process is newly proposed based on the first-principles calculation and on the finite element analysis in order to generate a new biocompatible piezoelectric thin film. Crystal growth process of lead-free BaTiO3 thin films was designed and experimentally generated on SrTiO3(100), (110), (111), and MgO(100) substrates using the radio-frequency magnetron sputtering method. Crystal structures of BaTiO3 were measured by X-ray diffraction (XRD) θ/2θ scan. We used Pt for the electrode and measured piezoelectric strain constants d 33 using the ferroelectric measurement system. As a result, analytical crystal orientation fractions on SrTiO3(110) and (111) substrates had good quantitative agreement with experimental ones, and ones on SrTiO3(100) and MgO(100) substrates corresponded with these experimental crystal structures. Furthermore, analytically determined piezoelectric strain constants d 33 qualitatively showed a good agreement with experimental ones. Especially, for SrTiO3(100) and MgO(100) substrates, the differences of d 33 depending on orientation fractions were analyzed by the three-scale simulation accurately. Consequently, it is confirmed that the three-scale analysis is a useful simulation tool to design new biocompatible piezoelectric thin films.

Microstructure and Properties of a (Bi0.95Na0.75K0.15Li0.05)0.5Ba0.05TiO3 Ceramic Thick Film Prepared by Electrophoretic Deposition

The changes in the microstructure and properties of a (Bi0.95Na0.75k0.15Li0.05)0.5Ba0.05TiO3 (BNKLT–BT) ceramic film were investigated when the ceramic film was deposited with the addition of platelike SrTiO3 (STO) via an electrophoretic deposition method. The platelike SrTiO3 (STO) was used as a template for inducing grain growth with a preferential orientation of [001], and as a protective plate for restraining some elements in the film from evaporating under heat treatment. The SrTiO3 templates were found to be an effective protective layer for restraining the evaporation of volatile elements when the templates are placed on the ceramic thick film. The STO/BNKLT–BT/STO/AgPd/Al2O3 samples were fabricated and heated at 1170 °C for 12 h. They showed a [001]-oriented texture structure and better ferroelectric properties. The textured microstructure could be observed with the occurrence of grain growth around the templates. When the maximum E (Emax) was 150 kV/cm, the textured film showed a remanent polarization (Pr) of 9 µC/cm2, which was larger than that of the nontextured film. The piezoelectric strain constant (d33*) derived from the slope of the strain curve was 62 pm/V for the textured film, which was 1.5 times that of the nontextured film.

Fabrication and Piezoelectric Properties of Textured (Bi1/2K1/2)TiO3 Ferroelectric Ceramics

Textured (Bi1/2K1/2)TiO3 (BKT) ceramics were prepared by a reactive templated grain growth (RTGG) method to improve their piezoelectric properties. Also, a hot-pressing (HP) method was modified on the basis of RTGG method to obtain dense ceramics and promote the grain orientation. The textured BKT ceramics prepared by the RTGG and HP methods exhibited a relatively high orientation factor F of 0.82 and a high density ratio of 95–99%. Scanning electron microscopy (SEM) micrographs of the textured HP-BKT indicated a textured and poreless microstructure. In addition, the resistivity of the textured HP-BKT was 1.73×1013 Ω·cm. The piezoelectric strain constant d33 determined by means of resonance and antiresonance method was 125 pC/N for the direction parallel to the sheet-stacking direction of the RTGG process. From the measurement of field-induced stain, the normalized d33* (=Smax/Emax) at 80 kV/cm were 127 and 238 pm/V on the randomly oriented and textured samples (F=0.82) for the (∥) direction, respectively.

Ferroelectric, piezoelectric and electrostrictive properties of Ba(Ti1−xSnx)O3 ceramics obtained from nanocrystalline powder

Abstract Ba(Ti1−xSnx)O3 powders with particle size 77.48 nm has been obtained through high energy ball milling. A detailed TEM study confirms the particle size to be 77.48 nm. Electromechanical coupling constant (Kp), piezoelectric strain constant (d33) and density follow decreasing trend with increasing tin concentration. As Sn concentration increases, ferroelectricity decreases with lower values of coercive field and remnant polarization, and this is due to replacement of Ti4+ ion by Sn4+ ion in the ABO3 structure of BaTiO3. Considerable strain values have been observed with very low value of degree of hysteresis and this implies good applicability of the ceramics.

Effects of Barium Substitution on the Structure and Properties of PSZT Piezoelectric Ceramics

Piezoelectric ceramics with appropriate curie temperatures and high dielectric and piezoelectric performances are attractive for formations of ceramic/polymer piezoelectric composites. The PSZT ceramics with compositions of 0.98Pb1.0-xBaxTi0.48Zr0.52O3-0.02PbSbO3 (x=0.14~0.24) have been prepared by a conventional solid reaction process. The ceramic structures are analyzed by X-ray diffraction and the barium substitution leads to structural changes of the tetragonal and rhombohedral phases which constitute the perovskite PSZT ceramics, and lattice distortions. The curie temperature almost linearly decreases from 226 °C to 141 °C corresponding the barium content increases from 0.14 to 0.24 in the ceramics. The dielectric and piezoelectric properties are largely influenced by the barium substitution and when the barium content at vicinity of 0.22, the piezoelectric strain constant d33 exhibits a dramatic change. It is found that as the barium content around 0.22, the PSZT ceramic specimen is characterized with a low curie temperature Tc=156 °C, and satisfied dielectric and piezoelectric properties with the relative dielectric constant εr=5873, dielectric loss factor tanδ=0.0387, piezoelectric strain constant d33=578 pC/N.

Electric-field-induced strain for (Bi1/2Na1/2)TiO3-based lead-free multilayer actuator

Multilayer prototype actuators were demonstrated using (Bi1/2Na1/2)TiO3 [BNT]-based ceramics as active layers and Pt as internal electrodes. One of the BNT-based solid solutions, 0.68(Bi1/2Na1/2)TiO3–0.04(Bi1/2Li1/2)TiO3–0.28(Bi1/2K1/2)TiO3 (BNLKT4–28) has been selected as the an active layer and it showed a relatively large piezoelectric strain constant d33 of 130 pC/N and a high depolarization temperature Td of 226°C. The total number of layers was 10 and the active layer thickness was 125 µm for the sintered body. The final compact dimensions were approximately 5 × 5 × 2 mm3. From the SEM observation, there were no apparent delaminations around the interface between Pt electrodes and active BNLKT layers. The large electric-field-induced strain at 70 kV/cm was 0.17% and the longitudinal dynamic displacement at the same electric field was 2.1 µm.

Development of a New Biocompatible MgSiO3 Piezoelectric Thin Film

PbTiO3 and Pb(Zr,Ti)O3, have been applied to various actuators and sensors due to their high piezoelectric and dielectric properties. However, the usage of lead-based materials is prohibited by Restriction of Hazardous Substances. In this study, a new biocompatible MgSiO3 thin film is generated on the Au/SrTiO3(110) substrate, which is determined on basis of our three-scale analyses, by using the radio-frequency magnetron sputtering method. The crystallographic orientation of thin film was measured by using X-ray diffractometer and the displacement-voltage curves were measured by using the ferroelectric character evaluation system, respectively. An optimum condition, which leads to the highest piezoelectric property, is determined through the experimental design algorithm and the analysis of variance table schemes. The peak of MgSiO3(111) crystal was obtained and its intensity increased with the substrate and the post-annealing temperatures. MgSiO3 thin films showed good piezoelectric properties, because they yielded the typical butterfly-type hysteresis curves. Additionally, the substrate temperature was significant at 1% level for piezoelectric strain constant d33. Optimum generating condition was obtained as Ts= 300 °C, Ta= 650 °C and fO2= 3.0 sccm, and its piezoelectric strain constant was d33= 346.7 pm/V, which was higher than the values of the existing piezoelectric BaTiO3.

Poling Field Dependence of Piezoelectric Properties and Hysteresis Loops of Polarization versus Electric Field in Alkali Niobate Ceramics

The DC poling field dependence of piezoelectricity was investigated to evaluate the mechanism of domain alignment in lead-free ceramics of the form of (1-x)(Na,K,Li,Ba)(Nb0.9Ta0.1)O3–xSrZrO3 (x=0–0.07) by comparison with those of Pb(Zr,Ti)O3 (PZT), PbTiO3 (PT), and BaTiO3 (BT) ceramics. Poling was conducted at 150 °C for 30 min while varying the poling field (E) between ±4.0 kV/mm. By increasing x from 0 to 0.07, the relative dielectric constant (εr), electromechanical coupling factor in the planar mode (kp), frequency constant in the kp mode (fcp), and piezoelectric strain constant (d33) vs E plots showed domain clamping at a specific E. E was the coercive field estimated from the DC poling field dependence. The changes in εr, kp, fcp, and d33 with E became smaller at x=0.06–0.07, because of the proximity to the paraelectric phase. The ceramics with x=0, such as PT or BT ceramics, show similar εr, kp, fcp, and d33 vs E plots. The maximum kp (48%) and d33 (307 pC/N) were obtained for x=0.05 with the lowest fcp of 2964 Hz·m, as shown in the εr, kp, fcp, and d33 vs E plots for ceramics such as tetragonal hard PZT ceramics. Since domain alignment in the ceramics was accompanied by the deformation of crystals as a result of applying the poling field, it was clarified that the lead-free ceramics must have a high kp and high d33 to realize a low fcp, which corresponds to a low Young's modulus. In addition, the optimal ceramic composition was obtained in the typical domain-clamping state from the poling field dependence. Furthermore, it was found that a higher kp was realized at a larger remnant polarization and a smaller coercive field in a symmetrical hysteresis loop of polarization vs electric field (P–E hysteresis loop), because of the easy alignment of ferroelectric domains by applying a poling field. The results of the poling field dependence were also supported by results of expansion strain measurement.

Large electric-field-induced strain in Bi0.5Na0.5TiO3–Bi0.5K0.5TiO3 solid solution single crystals

Single crystals of ferroelectric (1−x)Bi0.5Na0.5TiO3–xBi0.5K0.5TiO3 (BKT) solid solution with rhombohedral structure were grown by flux method in the composition range of 0<x<0.14. The polarization hysteresis, electric-field-induced strain, and temperature dependence of dielectric permittivity were investigated along the [100]cubic direction. Although small substitution of BKT suppressed the remanent polarization from 38 μC/cm2 at x=0 to about 15 μC/cm2 at x>0.02, piezoelectric strain constant (d33) was enhanced with increasing x up to 297 pm/V at x=0.14.

Influence of Strontium Ferrite on Properties of 0-3 Cement-Based Piezoelectric Composites

0-3 cement based piezoelectric composites were fabricated using sulphoaluminate cement as matrix by compressing technique method. The effects of strontium ferrite content on the piezoelectric properties, dielectric properties and acoustic impedance of the composites were studied. The results show that the piezoelectric strain constant d33 and piezoelectric voltage constant g33 of the composites increase gradually with increaing strontium ferrite content. When the strontium ferrite mass fraction is 0.4%, both of the piezoelectric strain constant d33 and piezoelectric voltage constant g33 of the composite have the maximum value, and the values are 16.6pC•N-1 and 31.4mV•m•N-1, which are 35% and 19% larger than that of the composite without strontium ferrite doped, respectively. With the strontium ferrite content increase, both of the dielectric constant εr and the dielectric loss tanδ of the composites increase. With the addition of strontium ferrite the acoustic impedance Z increases, but there is no obvious relation between the strontium ferrite content and Z.

Polarization and piezoelectric properties of grain-oriented ferroelectric Bi5FeTi3O15 ceramics prepared by magnetic-field-assisted electrophoretic deposition method

Magnetic-field-assisted electrophoretic deposition method has been employed for synthesizing a(b)-axis-oriented Bi5FeTi3O15 ceramics, and the effects of grain orientation and microstructure on the polarization and piezoelectric properties have been investigated. Grain-oriented Bi5FeTi3O15 ceramics with a high relative sintered density of 98% is shown to exhibit enhanced polarization and piezoelectric properties with a remanent polarization (P r) of 19 μC/cm2 and a piezoelectric strain constant (d 33) of 23 pm/V, which are much superior to those of randomly-oriented ceramics (P r of 7 μC/cm2 and d 33 of 5 pm/V).

Fabrication and Piezoelectric Properties of Grain-Oriented (Bi1/2K1/2)TiO3–BaTiO3 Ceramics

The piezoelectric properties of (1 - x)(Bi1/2K1/2)TiO3–xBaTiO3 (x = 0.1) [abbreviated as BKT–BT10] ceramics prepared by ordinary solid-state reaction and reactive templated grain growth (RTGG) using platelike Bi4Ti3O12 particles as a template were investigated. All samples showed a single-phase perovskite structure, and relative densities compared with theoretical densities were all higher than 95%. The degree of orientation F was determined by the Lotgering method using an X-ray diffraction (XRD) pattern. The F values of textured BKT–BT10 ceramics were relatively low at ∼35%. However, field-induced strains and piezoelectric properties of BKT–BT10 ceramics were improved by grain orientation. In particular, the piezoelectric strain constant d33 and the strain of textured BKT–BT10 ceramics in a direction parallel (∥) to the tape stacking direction were 84.5 pC/N and 168 pm/V (at 80 kV/cm), respectively.

Numerical Investigation on Identification of Piezoelectric Strain Constants on Basis of Displacement Response in Piezoelectric Thin Films

In order to characterize piezoelectric thin films fabricated on silica substrate, the relation between displacement response and piezoelectric strain constants have been analyzed by finite element method. At first, the effect of substrate dimensions on deformation was investigated when an electric load was applied to piezoelectric thin film by disc-type electrode. And then, a displacement measuring condition to reduce size dependence was searched by using two parameters, which are the thickness of piezoelectric thin film and the radius of top electrode. Computational results indicated that piezoelectric strain constant d33 of thin film has good correlation and its value can be identified with displacement response under the appropriate measuring condition.

An investigation on 1–3 cement based piezoelectric composites

1–3 cement based piezoelectric composites which had good compatibility with civil engineeringstructural materials were fabricated by the cut–fill technique. The piezoelectric, dielectricand ferroelectric properties of the composites were studied. The acoustic impedance of thecomposites was also investigated. The results show that the piezoelectric strain constantd33 and the dielectricconstant ε of the composites increase linearly with the increase of PMNvolume fraction, while the piezoelectric voltage constantg33 presents theopposite trend. The g33 values of the composites are much higher than those of pure PMN. The remnant polarizationPr and thecoercive field Ec of the composite with 27.26% volume fraction of PMN are4.12 µC cm−2 and 4.01 kV mm−1, respectively. By enhancing the PMN volume fraction, the acoustic impedance of thecomposites can be tailored to match that of the civil engineering structural material, i.e.concrete. Therefore, this new kind of composite has potential to be used in civil structurehealth monitoring.

Growth and electrical properties of large size Pb(In1∕2Nb1∕2)O3–Pb(Mg1∕3Nb2∕3)O3–PbTiO3 crystals prepared by the vertical Bridgman technique

Relaxor-based ferroelectric single crystals Pb(In1∕2Nb1∕2)O3–Pb(Mg1∕3Nb2∕3)O3–PbTiO3 (PIMNT) have been grown directly from their melt using the vertical Bridgman method, and their boules have reached the size of ϕ45×80mm. The as-grown PIMNT28/40/32 crystals on the (001) cuts exhibit a dielectric constant ε∼5200, dielectric loss tanδ∼0.50%, piezoelectric strain constant d33∼1700–2200pC∕N, electromechanical coupling factors kt∼0.61 and k33∼0.92, coercive field Ec∼10.88kV∕cm, remanent polarization Pr∼46μC∕cm2, Curie temperature TC∼192°C, and rhombohedral to tetragonal phase transition temperature Trt∼119°C. Moreover, their piezoelectric properties show good thermal stability under the heat treatment at 105°C.

Crystal Growth and Electric-Field-Induced Strain in Bi<sub>0.5</sub>Na<sub>0.5</sub>TiO<sub>3</sub> Crystals

Large Bi0.5Na0.5TiO3 (BNT) single crystals with 10 mm × 10 mm × 5 mm were successfully grown by a flux method using BNT powder and the mixed flux composed of Bi2O3 and NaF. Dielectric measurements show a dielectric-permittivity peak at 310°C, which is the result of the gradual phase transition from rhombohedral (R3c) to tetragonal (P4bm) structure. Electric-field induced strain measurements along [100]C reveal that the effective piezoelectric strain constant (d33 *) was estimated to be 130 pm/V in a multidomain state.

A Comparison of Dynamic Piezoactuation of Fiber-based Actuators and Conventional PZT Patches

This work aims to extend investigations of the dynamic flexural actuation of a cantilever beam to fiber-based actuators (e.g., active fiber composite (AFC) or macro-fiber composite (MFC)), which consist of a single level of unidirectionally aligned piezoceramic fibers surrounded by a polymer matrix and electrically loaded by interdigitated electrodes. The main advantage of such actuators is their poling in the same direction as the beam length, i.e., they are able to act with the piezoelectric strain constant d33 that is about two times higher than the piezoelectric strain constant d31 used in PZT patches. Modeling using the finite element method is based on the multiplication in both plane directions of a unit cell, which is taken as a fiber unit (with its matrix) within two pairs of half-electrodes of the same polarity. Modeling of the whole system is possible practically only with MFC actuators, whose fibers have a rectangular section, thus reducing the number of required finite elements. In addition to a non-uniform longitudinal free extension of the electrically loaded piezofiber-based actuator, a lateral free shearing has been calculated, which results in a non-planar deformation of the actuator. When two such MFC actuators are bonded on both sides of an aluminum cantilever beam and loaded in the antiphase mode, they conduct into all flexural resonance modes of the actuated beam, as expected. However, a slight interference by the torsion eigenmodes of the actuated beam has also been detected, which was not present in the actuation type using (leadzirconate titanate) PZT patches. The experimental validation of these FEM results first confirms the static values for free strain components of the MFC actuator depending on the loading voltage, then dynamic values regarding the eigenfrequencies, as well as the acceleration amplitudes of the MFC actuated vibrating beam.

Microstructure and piezoelectric properties of sub-80 nm high polycrystalline SrBi2Ta2O9 nanostructures within well-ordered arrays

Well-ordered arrays of sub-80 nm high SrBi2Ta2O9 nanostructures were fabricated on SrTiO3:Nb (111) single-crystal substrates by latex sphere lithography. The as-prepared nanostructures have a pyramid-like shape with around 220 nm lateral dimension at half their height. After annealing, the pyramid-like shape changes due to the formation of nano-sized SrBi2Ta2O9 grains of high crystal anisotropy in the individual nanostructures. Microstructure and piezoelectric properties of the nanostructures were investigated by cross-sectional transmission electron microscopy and piezoresponse force microscopy, respectively. Scattering in piezoelectric strain constants d33 was observed, probably arising from varying orientations, high anisotropy, and interfacial diffusion layer of the polycrystalline SrBi2Ta2O9 nanostructures on SrTiO3. The d33 increases continuously with dc bias and reaches 8pm∕V at a bias of 20 V. The size effect on piezoelectric properties of SrBi2Ta2O9 was found to be much less severe than that in BaTiO3. The acquired piezoresponse hysteresis loops proved that 30 nm high SrBi2Ta2O9 nanostructures are still ferroelectric.