Piezoelectric Strain Constant D33 Research Articles

Insights into Antisite Defect Complex Induced High Ferro-Piezoelectric Properties in KNbO3 Perovskite: First-Principles Study.

Improving ferro-piezoelectric properties of niobate-based perovskites is highly desirable for developing eco-friendly high-performance sensors and actuators. Although electro-strain coupling is usually obtained by constructing multiphase boundaries via complex chemical compositions, defect engineering can also create opportunities for novel property and functionality advancements. In this work, a representative tetragonal niobate-based perovskite, i.e., KNbO3, is studied by using first-principles calculations. Two intrinsic types of Nb antisite defect complexes are selected to mimic alkali-deficiency induced excess Nb antisites in experiments. The formation energy, electronic profiles, polarization, and piezoelectric constants are systematically analyzed. It is shown that the structural distortion and chemical heterogeneity around the energetically favorable antisite pair defects, i.e., (NbK4·+KNb4'), lower the crystal symmetry of KNbO3 from tetragonal to triclinic phase, and facilitate polarization emergence and reorientation to substantially enhance intrinsic ferro-piezoelectricity (i.e., spontaneous polarization Ps of 68.2 μC/cm2 and piezoelectric strain constant d33 of 228.3 pC/N) without complicated doping and alloying.

Preparation of porous lead zirconate titanate piezoelectric ceramics via vat photopolymerization combined with burnt polymer spheres technique

Porosity plays an important factor on the electric properties of piezoelectric ceramics. Here, we propose a promising method for the fabrication of Lead zirconate titanate (PZT) piezoelectric ceramics using vat photopolymerization, and effectively modulate porosity of printed PZT piezoceramics through adjusting the polystyrene (PS) content. After a post-process, the PZT piezoelectric ceramics showed single perovskite structure and porous microstructures formed by PS, with porosity ranging from 8.57 % to 27.02 %. With the increase of porosity, the piezoelectric strain constant (d33) and dielectric permittivity (ɛr) decreased gradually due to the reduction in the volume fraction of PZT phase per unit volume. When the PS content was 20 vol%, d33 and ɛr reached the maximum values. The sintered PZT piezoelectric ceramics exhibited excellent electrical properties (ɛr=2364, d33=399 pC/N, g33=1.91×10−2 Vm/N, d33g33=7.62×10−12 m2/N and Kt=43.94 %). This work not only provides technical support for manufacturing advanced ceramics with tunable porosity through the use of PS powders, but also lays the foundation for preparing functional ceramics with complicated designed structures through vat photopolymerization technology.

Magnetism, ferroelectricity, and piezoelectricity in bulk α-CrOOH and its monolayer

Multifunctional materials with magnetic, piezoelectric, and ferroelectric properties have a wide range of applications. This study investigates the properties of bulk α-CrOOH and its monolayer using density functional theory. The findings reveal that bulk α-CrOOH exhibits a weak interlayer antiferromagnetism, but has a ferroelectric polarization of 28.45 µC/cm2 and piezoelectric strain constants d33 of 21.69 pm/V, which are comparable to those of the multiferroic material BiFeO3. The monolayer of α-CrOOH is a low-temperature ferromagnetic semiconductor that exhibits robust piezoelectricity. This is because of the intrinsic mirror symmetry breaking in the z-direction, resulting in large out-of-plane piezoelectric coefficients of e31 = 31.914 pC/m and d31 = 0.22 pm/V. These intriguing electric and magnetic properties make polarized bulk and monolayer α-CrOOH potential candidates for piezoelectric and ferroelectric device applications.

Castor‐oil derived polyurethane/barium titanate piezoelectric smart composite coatings for energy harvesting applications: Prediction and experimental characterization of electro‐elastic properties

AbstractSustainable and environment‐friendly polymer composite smart paints/coatings with polyurethane (PU) derived from castor‐oil (CO) as the matrix and barium titanate (BTO) microparticles as piezo‐active inclusions (2, 4, 6, 8, and 10 vol.%) have been prepared employing ultrasonication and solvent casting, followed by contact DC poling method. Relative dielectric constants varied from 5.26 ± 0.37 for pristine COPU to 8.9 ± 0.36 for COPU/10 vol.% BTO composite, at a frequency of 1 kHz. Piezoelectric strain constant d33 of the poled films varied from 0.0 pC/N for pristine castor‐oil based polyurethane (COPU) to 1.2 pC/N for COPU/10 vol.% BTO (CPBT‐5) composite. Tensile tests showed that the elastic modulus varied from 1.98 ± 0.003 MPa for pristine COPU to 5.13 ± 0.02 MPa for COPU/10 vol.% BTO composite. Dynamic mechanical analysis confirmed the viscoelastic nature of the smart paints. Measurement of current–voltage response under different compressive loads indicates that COPU/10 vol.% BTO composite can generate a current of ~28 nA and voltage of ~8 V under a dynamic compressive load of 40 N, applied at a frequency of 1 Hz. These experiments were complemented by Fourier transform infra‐red spectroscopy and scanning electron microscopy. In addition, finite element analyses based on periodic boundary conditions have been performed to predict the effective electro‐elastic properties of these piezoelectric smart composite coatings.Highlights Castor‐oil‐based PU piezoelectric composites with BTO inclusions were developed. Increase in BTO content up to 10 vol.% increases dielectric constant by ~1.7 times. COPU/BTO composites exhibit significantly increased piezoelectric response. Elastic and viscoelastic properties are also enhanced with increasing BTO content. Finite element models show a good match with experimental results.

Electrical output performance of PZT-5H under the superposition of temperature, temperature change rate and pulse stress

The static pyroelectric coefficient of PZT-5H thin slice was measured. The effects of temperatures, temperature change rates and pulse stress on the discharge characteristics of PZT under different electrical boundary conditions (open circuit and short circuit) were investigated by an improved split Hopkinson pressure bar system; The effects of temperature change rate and the pulse stress on dynamic piezoelectric coefficient and discharge characteristics of PZT were analyzed. The results show that the static pyroelectric coefficient of the piezoelectric ceramics is 4.16 × 10−8 C/cm2·°C. The piezoelectric voltage constant g33(σ, ∂ΔT), piezoelectric strain constant d33(σ, ∂ΔT), elastic compliance coefficient S and electromechanical coupling coefficient k were obtained by experiments at the given temperature and different temperature change rates.

Ferroelectricity and Piezoelectric Response of (Sc,Y)N/(Al,Ga,In)N Monolayer Alternating Stacked Structures by First‐Principles Calculations

Group III‐nitrides with doping recently attract great interest because of their outstanding ferroelectric and piezoelectric properties. Herein, the spontaneous polarization and piezoelectricity of the wurtzite III‐nitrides (AN, A = Al, Ga, In) with the rare earth element (R = Sc, Y) doping (w‐R0.5A0.5N) are investigated by first‐principles calculations. The polar w‐R0.5A0.5N and nonpolar h‐R0.5A0.5N are stable, which is proved by the elastic constants and phonon band structures. The w‐Sc0.5In0.5N and w‐Y0.5In0.5N can be applied to the ferroelectric field owing to their very small ferroelectric switching barriers (0.149 eV for w‐Sc0.5In0.5N and 0.042 eV for w‐Y0.5In0.5N) with large ferroelectric polarization (1.088 C m−2 for w‐Sc0.5In0.5N and 0.937 C m−2 for w‐Y0.5In0.5N). Furthermore, the w‐Y0.5In0.5N has a large piezoelectric strain constant d33 (14.018 pC N−1) based on the elastic constant C33 softening and the increase of the piezoelectric constant e33, which is three times larger than that of w‐InN (4.191 pC N−1). It is found that the biaxial tensile strain of 2% along in‐place significantly enhances the d33 and e33, which increase to 35.572 pC N−1 and 2.669 C m−2 from 14.018 pC N−1 and 1.700 C m−2 of free w‐Y0.5In0.5N, respectively.

Piezoelectric property of PZT nanofibers characterized by resonant piezo-force microscopy

Nano-piezoelectric materials have drawn tremendous research interest. However, characterization of their piezoelectric properties, especially measuring the piezoelectric strain coefficients, remains a challenge. Normally, researchers use an AFM-based method to directly measure nano-materials’ piezoelectric strain coefficients. But, the extremely small piezoelectric deformation, the influence from the parasitic electrostatic force, and the environmental noise make the measurement results questionable. In this paper, a resonant piezo-force microscopy method was used to accurately measure the piezoelectric deformation from 1D piezoelectric nanofibers. During the experiment, the AFM tip was brought into contact with the piezoelectric sample and set to work at close to its first resonant frequency. A lock-in amplifier was used to pick up the sample’s deformation signal at the testing frequency. By using this technique, the piezoelectric strain constant d33 of the Lead Zirconate Titanate (PZT) nanofiber with a diameter of 76 nm was measured. The result showed that d33 of this PZT nanofiber was around 387 pm/V. Meanwhile, by tracking the piezoelectric deformation phase image, domain structures inside PZT nanofibers were identified.

3D printed 0–3 type piezoelectric composites with high voltage sensitivity

Piezoelectric composites made of piezoelectric ceramic particles and polymer composites combine the performance advantages of both components and have broad application prospects. However, the preparation of complex structures is still a challenge, for which 3D printing technology provides a perfect solution. The aim of the present study is to investigate the principle and process optimization of the stereolithography of 0–3 type piezoelectric composites through simulation and experiments. In particular, a modified three-phase model of a spherical shell is applied to elucidate the influence of the elastic modulus between the ceramic particles and the matrix on the piezoelectric properties of the composites at the macroscopic level. This enables the piezoelectric properties of the composites to be predicted more accurately, and guides the surface grafting modification of piezoelectric ceramic powders. Furthermore, the problem of weak interface bonding in piezoelectric composites caused by poor compatibility between hydrophilic particles and the hydrophobic matrix is successfully solved by preprocessing the PZT ceramic powder via activating the particle surface hydroxyl groups and grafting a silane coupling agent onto the piezoelectric ceramic powder. As a result, the particles are bonded to the matrix by covalent bonds, which increases the elastic modulus of the interface transition layer and modifies the stress transfer efficiency. For instance, the piezoelectric strain constant (d33) of piezoelectric composite containing 60 wt% functionalized PZT particles is increased from 20 to 37 pC/N. The printing accuracy, piezoelectric properties, and mechanical characteristics of the piezoelectric composites are thoroughly investigated, and the reliability of the proposed theoretical model and simulation results is verified. The piezoelectric composites are uniformly compact and have a low residual pore rate. The piezoelectric composite with a solid content of 60 wt% has a volume density of 2.27 g/cm3 and a Young's modulus of 535.44 MPa. Most importantly, its piezoelectric voltage constant (g33) is 167.2 × 10−3 Vm/N, which is more than seven times higher than that of homogeneous PZT and results in high voltage sensitivity.

Enhancing the Temperature Stability of 0.42PNN-0.21PZ-0.37PT Ceramics through Texture Engineering.

Although the MPB composition 0.42PNN-0.21PZ-0.37PT ceramic has high piezoelectric properties, its temperature stability at room temperature is rather poor due to the low phase-transition temperature. By texture engineering using BaTiO3 (BT) as the template, the temperature stability of this material can be greatly improved. In the temperature range from room temperature up to 140 °C, the high effective piezoelectric strain constant d33* of 0.42PNN-0.21PZ-0.37PT-3BT only changed by 4.9% from 1278 to 1215 pm/V, while the d33* of the nontextured counterpart changed by 46.7% from the room temperature value of 920 pm/V with the maximum deviation to 1350 pm/V at 80 °C. In addition, the textured ceramic has higher piezoelectric properties, lower dielectric loss, and slightly higher coercive field. The room-temperature figure-of-merit d33 × g33 for PNN-PZT-2BT is increased by as much as 42% compared with the nontextured counterpart. Our results demonstrated that texture engineering is an effective way to improve the temperature stability of the MPB composition piezoceramics.

Effects of piezoelectric and dielectric properties of (Bi0.5Na0.5) TiO3-Ba (Ti, Zr) O3ceramics

Lead-free piezoelectric ceramics Zr and Mn-doped Ba (ZrxTi1-x) O3-0.5 mol% MnO2 (BZT100x-Mn, x=0.04, 0.045, 0.05, 0.055, 0.06 and 0.065) have been fabricated by the conventional solid-state reaction technique. The effects of Zr on the microstructure and electrical properties of the samples have been studied. The results revealed that the specimens exhibit the perovskite structure and a small amount of MnO2 can improve effectively the densification and electrical insulation of the ceramics. Because of high densification, good electrical insulation the donor-and acceptor-doping effects of MnO2, the piezoelectric and dielectric properties of ceramics are improved considerably. The ceramics shows an excellent piezoelectric strain constant d33 as 213 pC/N. A distinct positive temperature coefficient of resistance (PTCR) effect over a wide temperature range has been observed in all samples. With the addition of 0.5 mol% MnO2, the sample Ba(ZrxTi1-x)O3-0.5 mol% MnO2 with x=0.06 (BZT6-Mn) ceramics display low ρ values of 103 Ω cm at room temperature and their abrupt changes of 102-103 near Curie Temperature.

Large Piezoelectric Response and Ferroelectricity in Li and V/Nb/Ta Co-Doped w-AlN.

Enhancement of piezoelectricity in w-AlN is desired for many devices including resonators for next-generation wireless communication systems, sensors, and vibrational energy harvesters. Based on density functional theory, we show that Li and X (X = V, Nb, and Ta) co-doping in 1Li:1X ratio transforms brittle w-AlN crystal to ductile, along with broadening the compositional freedom for significantly enhanced piezoelectric response, promising them to be good alternatives to expensive Sc. Interestingly, these co-doped w-AlN also show quite large spontaneous electric polarization (e.g., about 1 C/m2 for Li0.125X0.125Al0.75N) with the possibility of ferroelectric polarization switching, opening new possibilities in wurtzite nitrides. An increase in piezoelectric stress constant (e33) with a decrease in elastic constant (C33) results in an enhancement of piezoelectric strain constant (d33), which is desired for improving the performance of bulk acoustic wave (BAW) resonators for high-frequency radio frequency (RF) signals. Also, these co-doped w-AlN are potential lead-free piezoelectric materials for energy harvesting and sensors as they improve the longitudinal electromechanical coupling constant (K332), transverse piezoelectric strain constant (d31), and figure of merit (FOM) for power generation. However, the enhancement in K332 is not as pronounced as that in d33 because co-doping increases dielectric constant. The longitudinal acoustic wave velocity (7.09 km/s) of Li0.1875Ta0.1875Al0.625N is quite comparable to that of commercially used piezoelectric LiNbO3 or LiTaO3 in special cuts (about 5-7 km/s) despite the fact that the acoustic wave velocities, important parameters for designing resonators or sensors, decrease with co-doping or Sc concentration.

Dielectric and ferroelectric properties of (Bi0.5Na0.5)0.94-δBa0.06Ti1−xNbxO3 lead-free ceramics

Lead-free ceramics (Bi0.5Na0.5)0.94-δBa0.06Ti1−xNbxO3 (x = 0, 0.01, 0.02, 0.03, 0.04, 0.05) were prepared via a solid-state sintering method. The ceramics exhibit pure perovskite structure as x ≤ 0.04, while the ceramic with x = 0.05 has a secondary phase. The rhombohedral (R)–tetragonal (T) morphotropic phase boundary exists in all the samples. The relative content of the T phase increases due to the Nb5+ doping. The ceramics show dense microstructures with mean grain sizes around 1–2 μm. The changes of dielectric constant and dielectric loss as a function of temperature for the unpoled and poled samples were compared. Two dielectric anomalies appear on the dielectric curves around the temperatures denoted as TRE and Tm. With the increase of Nb5+ amount, the values of TRE decrease and Tm increase. The Nb5+-doped ceramics exhibit better temperature stability of dielectric constant during a wide high-temperature window. The polarization hysteresis (P–E) loops change from typical ferroelectric loops for the sample with x = 0 to constricted P–E loops with increasing Nb5+ amount. The ceramic with x = 0.03 shows a maximum strain (Smax) of 0.55% and piezoelectric strain constant (d33*) of 675 pm/V.

High thermal stability of piezoelectric properties in tetragonal Pb(In1/3Nb2/3)O3-PbTiO3 single crystal

The representatives of relaxor ferroelectric (1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 (PZNT) and (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMNT) have been extensively studied due to their excellent dielectric and piezoelectric properties near the morphotropic phase boundary (MPB). However, low rhombohedral to tetragonal phase transition temperature and Curie temperature directly affect the performance and stability of devices, particularly for high-power ultrasonic transducers. In this paper, the large size tetragonal 0.62Pb(In1/2Nb1/2)O3-0.38PbTiO3 (PINT) crystal was grown by the modified Bridgman technique. The crystals were oriented along the ⟨100⟩ direction to make bars with electrodes on (001) faces. The variation of the dielectric constant with temperature showed that the Curie temperature of PINT was 250 °C, and the maximum dielectric constant was 7.29 × 104 ɛ0. Fitting with Curie-Weiss’s law, we obtained that the relaxation degree was 1.44, which could mean that the dielectric properties of PINT are between relaxor ferroelectric and ordinary ferroelectric. At room temperature, electromechanical coupling coefficient k31 and piezoelectric strain constant d31 were 0.56 and 551 pC/N, respectively. Piezoelectric properties were relatively stable between room temperature and 175 °C. The material has good temperature stability in terms of piezoelectricity and dielectric properties. These results proved that the working temperature of the PINT crystal could reach about 175 °C, much higher than PZNT and PMNT single crystal, indicating their application in ultrasonic transducers at high temperatures.

Preparation, mechanical and electric properties of polypropylene fiber reinforced lead zirconate titanate flexible materials

The preparation and properties of polypropylene fiber (PPF) reinforced lead zirconate titanate (PZT) flexible materials were investigated in this paper. PPF reinforced PZT composites were prepared by hot pressing. The microstructure, mechanical and electrical properties of PPF reinforced PZT composited were tested by Scanning Electron Microscope (SEM) technology, Universal tester, d33 quasi-static tester and LCR tester and were systematically characterized. The results showed that with the increase of PPF volume fraction, the reticular structures in the composites increase, and the bending strength σc and tensile strength σb of the composites increase; meanwhile, the relative dielectric constant εr and dielectric loss tanδ of the composites decreased gradually, but the piezoelectric strain constant d33 of the composite increases first and then decreases with the increase of PPF volume fraction. When the PPF volume fraction is 50%, the composite has superior mechanical properties and comprehensive electrical properties, and is relatively in mechanical electrical equilibrium with σc is 25.402 MPa, σb is 7.049 MPa, εr is 77.216 and d33 is 15 pC N−1.

Improved output voltage of 0–3 cementitious piezoelectric composites with basalt fibers

In this paper, basalt fibers (BF) was employed as high modulus component with good interface bonding with cement matrix to enhance local stress applied on piezoelectric ceramic particles in 0–3 cementitious piezoelectric composites (0–3 CPCs). The effect of content of BF varying from 0.00 vol% to 0.23 vol% on the mechanical, piezoelectric and dielectric properties of 0–3 CPCs and the output voltage of 0–3 CPCs sensor was evaluated. The results showed that amplitude of output voltage of the 0–3 CPCs sensor with 0.12 vol% BF maximized at 4.98 V, which was 60.0% higher than that of the 0–3 CPCs sensor without fibers for the compact structure of the 0–3 CPCs and good interface bonding between BF and cement matrix as a reason of good stress transfer in the composites. While the split tensile strength, piezoelectric voltage constant (g33), piezoelectric strain constant (d33), relative dielectric constant (εr) and dissipation factor (tanδ) was 13.1 MPa, 11.36 × 10−3 V m/N, 43 pC/N, 430.0 and 0.43, respectively. It provided a novel method to improve the mechanical-electrical response of piezoelectric sensor by enhancing local stress applied on piezoelectric ceramic particles in the piezoelectric composites.

Enhanced piezoelectric output of the PVDF-TrFE/ZnO flexible piezoelectric nanogenerator by surface modification

In this paper, ZnO nano-particles (NPs) were modified by adding a dispersant (n-propylamine, PA) and a silane coupling agent (1H, 2H, 1H, 2H, Perfluorooctyltriethylsilane, PFOES) simultaneously. Further, the PVDF-TrFE/modified ZnO composite films with high crystallinity and large specific surface area were prepared, which acted as the active layer of the piezoelectric nanogenerator (PENG). Four species of films, pure PVDF-TrFE, PVDF-TrFE/ZnO, PVDF-TrFE/ZnO@PA and PVDF-TrFE/ZnO@PA@PFOES were marked P-0-0-0, P-Z-0-0, P-Z-P-0 and P-Z-P-P, respectively. The crystalline phases of the films were determined by Fourier infrared spectroscopy (FT-IR) and wide-angle X-ray diffraction (WXRD). Scanning electron microscope (SEM), Laser scanning confocal microscope (LSCM), Atomic force microscope (AFM) and water contact angle (WCA) measurements were employed to analyze the surface morphology of the films. The thermal properties of the materials were characterized with a differential scanning calorimeter (DSC). From the FTIR spectra and WXRD pattern, it was notable that the modified ZnO NPs promoted the crystallization of β-phase. The results showed that the crystallinity of P-Z-P-P was increased by 36.12% compared to P-0-0-0. Combined with the results of SEM, LSCM and AFM, it can be concluded from WCA that modified ZnO NPs can increase the specific surface area of the film. The piezoelectric strain constant d33 value of P-Z-P-P film was 73.5% higher than that of P-0-0-0 film, and the output voltage value of ITO/P-Z-P-P/Au PENG increased 24.4% than that of ITO/P-0-0-0/Au PENG. After 1000 cycles of testing, the output voltage of the ITO/P-Z-P-P/Au PENG has been maintained at 2.40 V, indicating that the generator exhibited the high mechanical endurance. By clarifying the mechanism of surface modification, it can be concluded that enhanced piezoelectric output of the PENG is contributed to both higher β-phase content and larger charge collecting area by surface modification.

Grain size effect on electric properties of novel BaTiO3/PVDF composite piezoelectric ceramics

Researches on barium titanate ceramics have been prosperous since its lead-free feature. In this paper, we classified the BaTiO3 ceramics into four different groups to study the effect of grain size on the electrical properties. According to the analysis of element, size distribution, conductivity, piezoelectric, and dielectric properties, we found that group #3, compounded distribution where the majority is small size, exhibited the best performance among four groups. The dielectric constant εr and piezoelectric strain constant d33 of BaTiO3/PVDF composites reached the maximum values which were 168.86 and 28pC/N, respectively, and dielectric loss tanδ maintained around 0.02.

Grain size effect on piezoelectric properties of BaTiO3 ceramics

We demonstrated the grain size effect on piezoelectric properties of pure BaTiO3 ceramics. BaTiO3 ceramics with various grain sizes were prepared by conventional and two-step sintering methods. The piezoelectric strain constant d33 increased with decreasing grain size when the grain size was more than 1.2 µm, whereas it decreased when the grain size was below 1.2 µm. The maximum d33 was 460 pC/N, which is approximately three times larger than that of coarse BaTiO3 ceramics. The increase in d33 was well explained by the domain-wall contribution, while the decrease in d33 was understood as the grain boundary effect. On the other hand, the piezoelectric voltage constant g33 increased with decreasing grain size down to 0.6 µm. The piezoelectric constants d33 and g33, and the mechanical quality factor Qm can be controlled by the grain size of BaTiO3 ceramics.

Enhanced thermo-electro-mechanical characteristics of purified P(VDF-TrFE) films for ultrasonic transducers

In this study, the fabrication process of a piezoelectric poly[(vinylidenefluoride-trifluoroethylene) [P(VDF-TrFE)] film was optimized to maximize its crystallinity and piezoelectric properties and to improve its thermal stability. The effect of purification of P(VDF-TrFE) solution dissolved in methyl ethyl ketone [MEK] and uniaxial stretching on the properties and performance of P(VDF-TrFE) film was studied. In the purification process, the solution was filtered with a syringe filter with 2.7 μm pores. X-ray diffraction measurements showed that the stretching and purification processes increased the crystallinity of the P(VDF-TrFE) films by approximately 16.2% and 2.2%, respectively. A high-temperature storage test showed that the unstretched P(VDF-TrFE) films lose most of their polarization after 1-h storage at 70 °C. The stretching process greatly increased the thermal stability of the films so that the purified and stretched P(VDF-TrFE) films exhibited a small variation within 6% in the piezoelectric strain constant (d33) for 96 h at 70 °C. Ultrasonic transducers (UTs) were also fabricated with the purified and stretched P(VDF-TrFE) films. The pulse-echo measurement showed that the sensitivity and bandwidth of the UTs increased by 4.5 dB and decreased by 24.3%, respectively, compared to UTs fabricated with the purified P(VDF-TrFE) film without stretching.

Effects of conductive carbon black on PZT/PVDF composites

ABSTRACTIn this paper, the hot-pressing method is selected to prepare piezoelectric vibrator. The effects of different volume ratio of PZT on the dielectric, piezoelectric and mechanical properties of the composites are studied. With the increase of PZT volume fraction in a certain range, the density of the composites, the dielectric constant (ɛ), the dielectric loss (tanδ) and the piezoelectric strain constant (d33) are all increased, while the piezoelectric voltage constant (g33) tends to change smoothly, however, the deformation and compressive yield strength are decreased. The mechanical and piezoelectric properties of the composites are improved after the addition of conductive carbon black particles. The results show that the conductive carbon black can make the structure more compacted and improve the conductivity (σ) of PZT/PVDF composites.