PZT Particles Research Articles

Development of Stretchable PZT/PDMS Nanocomposite Film with CNT Electrode

The piezoelectric composite film of ferroelectric PZT ceramic (PbZrxTi1-xO3) and polymer (PDMS, Polydimethylsiloxane) was prepared to improve the flexibility of piezoelectric material. The bar coating method was applied to fabricate flexible nanocomposite film with large surface area by low cost process. In the case of using metal electrode on the composite film, although there is no problem by bending process, the electrode is usually broken away from the film by stretching process. However, the well-attached, flexible CNT electrode on PZT/PDMS film improved flexibility, especially stretchability. PZT particles was usually settled down into polymer matrix due to gravity of the weighty particle, so to improve the dispersion of PZT powder in polymer matrix, small amount of additives (CNT powder, Carbon nanotube powder) was physically mixed with the matrix. By stretching the film, an output voltage of PZT(70 wt%)/PDMS with CNT (0.5 wt%) was measured.

Evaluation of the homogeneity in Pb(Zr,Ti)O3–zirconia composites prepared by the hetero-agglomeration of precursors using the Voronoi-diagram approach

Hetero-agglomeration of precursor particles was employed to achieve a homogeneous distribution of tetragonal zirconia (TZ) grains within a lead zirconate titanate (PZT) ceramic matrix. The surface charge of the zirconia particles in the aqueous suspension was modified by the addition of citric acid. At pH 5, the citric-acid-modified TZ particles were negatively charged, while the PZT particles were positively charged, which led to the agglomeration of the two types of particles. The homogeneity of the TZ distribution in the PZT–TZ ceramic composites prepared from the hetero-agglomerated particles was evaluated using Voronoi-diagram analyses. The results showed that the homogeneity of the composites prepared using the citric-acid-modified TZ particles was higher than in the case where the TZ particles were not modified. The curves for the crack-growth resistance were also determined in order to investigate the impact of particle homogeneity on the fracture behavior.

Thermal and dielectric behavior of flexible polycarbonate/lead zirconate titanate composite system

ABSTRACTPolycarbonate (PC)/Lead Zirconate Titanate (PZT) composites were prepared using solution mixing method followed by hot pressing. The volume fraction of PZT particles was varied from 0 to 27.5%. SEM showed good dispersion of PZT in the PC matrix. XRD confirmed the perovskite structure of PZT and amorphous structure of polycarbonate. The dielectric constant of the composites measured at 1 kHz, increased ∼3.5‐fold compared with pure PC. The modified Lichtenecker equation agreed well with the experimental data. There was no dispersion in the dielectric constant of the composites for the frequency range of 1 kHz to 10 MHz. However, at frequencies higher than 10 MHz significant drop in dielectric constant was observed. The dissipation factor of the composites was found below 0.02. However, above 1 MHz, an abrupt increment in the dissipation factor was observed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39913.

Polymer-Assistant Hydrothermal Synthesis of 2.6 nm-Sized Lead Zirconate Titanate Nanoparticles

A facile synthesis route for monodispersed lead zirconate titanate (PZT) nanoparticles was developed by simple hydrothermal reactions under the assistance of polymer blend including polyvinylalcohol (PVA) and polyacrylate acid (PAA). It was found that PZT particles with an average size of 2.6 nm as well as a very narrow size distribution could be obtained with a 19.0 g/L polymers solution under a low KOH concentration of 2 mol/L at 200 °C for 14 h, indicating that the polymer additives played an important role in controlling the morphology and size of PZT crystals. The simple polymer-assistant hydrothermal synthesis is feasible for the mass production of PZT nanoparticles and is expected to be used in the miniaturization of electronic devices.

Effect of milling time and pH on the dispersibility of lead zirconate titanate in aqueous media for inkjet printing

Micrometre-sized Pb(Zr 0.53 Ti 0.47 )O 3 (PZT) powder was dispersed in water, stabilized with the ammonium polyacrylate (PAANH 4 ) and milled to reduce the particle size. The influence of the pH, the amount of PAANH 4 , and the milling time on the zeta potential, the PZT particle size and the particle size distribution was studied. The agglomeration took place regardless the milling time at pH 3. The suspension, containing 5 vol.% of PZT and 5 wt.% of PAANH 4 , milled at pH 10 for 240 min, was stable and contained particles with a narrow, log-normal particle size distribution with the median size of 160 nm. The dissociated carboxyl groups from the PAANH 4 interacted with the PZT particles as evidenced by Fourier transform infrared spectroscopy and electrosterically stabilized the particles in water at pH 10. The PZT particle size and the stability of the suspension fitted the requirements for the ink, suitable for ink-jet printing.

Performance improvement of piezoelectric‐rubber by particle formation of linear aggregates

ABSTRACTWe investigate the piezoelectric response of piezoelectric‐rubber consisting of lead zirconate titanate (PZT) particles and silicon rubber prepared by holding it at 100°C for 60 min. Two types of piezoelectric‐rubber were used; one was mixed with PZT particles forming linear aggregates, and the other was mixed with PZT particles forming a random dispersion. The piezoelectric‐rubber whose PZT particles were aligned normal to the rubber surface had much higher piezoelectric effect than the type of piezoelectric‐rubber whose PZT particles were randomly dispersed. The reason for this is that force applied on the former is directly transmitted to PZT particles and the electric charges generated from PZT particles had higher mobility because of the aligned PZT particles, which were connected with each other. As a result, the formation of linear aggregates of PZT particles in rubber was effective in enhancing piezoelectric properties of piezoelectric‐rubber. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39862.

Fabrication of dome-shaped PZT-epoxy actuator using modified solvent and spin coating technique

Thick film two phase, 0–3 composite PZT-epoxy dome-shaped structures have been fabricated for the first time using a modified solvent and spin coating technique, where a PZT and ethanol solution was dispersed in an epoxy matrix, combined with a hardener, spin coated onto stainless steel sheets, and poled at ~2.2 kV/mm. The electro-mechanical performances of the films were investigated as a function of volume fraction of PZT. The volume fraction of PZT was varied from 0.1 to 0.7 and the piezoelectric coefficients d 31 and d 33 , and the capacitance, C, were measured, and used to calculate the effective dielectric constants. The values for d33, d31, C and dielectric constant were 1.06 pC/N, 0.74 pC/N, 6.0 pF and 76.1 respectively, at 70 % volume fraction of PZT. The surface topography and morphology were examined via AFM and SEM. The piezoelectric strain coefficients, capacitance and effective dielectric constant increased with increasing PZT content, in addition to the surface roughness. Agglomeration of PZT particles and surface crevices were observed on sample surfaces, which are most likely due to surface tension and air bubbles formed during the mixing process.

Sol-solvothermal synthesis and characterization of fine lead zirconate titanate particles

We present a novel low-temperature sol-solvothermal method to synthesize fine lead zirconate titanate (PZT) particles. This sol-solvothermal method combines the advantages of conventional sol–gel process and the solvothermal method, and isopropyl alcohol (IPA) was used as the solvent. The effects of different parameters including KOH concentration, IPA/(IPA + water) ratio and reaction temperature, on the microstructures of the PZT powder were studied. With increasing KOH concentration and reaction temperature, the crystalline structure of as-synthesized PZT transformed from tetragonal to rhombohedral phase. More IPA added in the solvent can effectively reduce agglomeration of the PZT powder and decrease the crystallization temperature, but impurity phase was also detected at high IPA/(IPA + water) ratio. As a result, the synthesis parameters are optimized, and well-crystallized 700 nm PZT particles were successfully synthesized in 2.0 M KOH and 50 % IPA/(IPA + water) ratio at temperatures as low as 120 °C.

Study on Lead Zirconate-Titanate/Interpenetrating Polymer Network Composites

In order to improve damping properties of polyurethane/vinyl ester resin interpenetrating polymer network (PU/VER IPN), a series of Lead Zirconate-Titanate/IPN (PZT/IPN) composites were prepared by adding PZT into PU/VER IPN by in-situ polymerization process and were polarized. The optimal polarization process is obtained. The influence of PZT contents on microstructure, damping performances, mechanical performances, relative dielectric constant and piezoelectric constant (d¬33) was studied. The results show that PZT particles disperse in composites uniformly. The optimal polarization parameters of PZT/IPN composites are as follows: polarization temperature 100°C, polarization field strength 6kV/mm and polarization time 40min. Mechanical loss tangent (tanδ) values of the optimal PZT/IPN composites with 75 wt.% PZT are higher than 0.3 from –31°C to higher than 120°C, which meets the requirement of damping materials with excellent performances.

PZT–PDMS composite for active damping of vibrations

A Lead Zirconate-Titanate (PZT)/poly-dimethylsiloxane (PDMS) based flexible composite is synthesized and investigated for its potential in significantly enhancing the vibration damping capability along with its tunable properties. Rheologically and functionally different PZT/PDMS composites are prepared by dispersing different volume fractions of piezoelectric soft/hard PZT and Fe particles in a cross-linked PDMS matrix. It is observed that passive damping increases with increase in the soft PZT volume fraction from 0 to 0.32. This effect becomes more prominent after poling the composite at optimum conditions. The loss factor depends on the viscoelastic properties of the PDMS, homo and hetero-particle connectivity in the composite, and polarization and localization of the PZT particles in composite. Rheological analysis of the composite shows that the material loss factor (tand) increases linearly from � 0.3 to 0.75 along with a broadening of the peak when the PZT volume fraction is increased from 0 to 0.32. Maximum structural damping ( g) is obtained at 0.32 (V/V) of the soft-PZT as measured by the Oberst beam technique. This effect becomes more pronounced after a poling treatment. The X-ray diffraction results indicate that the dispersed PZT particles in PDMS matrix have the lattice parameters of a = 5.84 A, c = 14.41 A and (0 0 1) orientation. Further, after poling treatment, the dielectric constant and the piezoelectric coefficient (d33) for soft (submicron) PZT filler particles in PDMS matrix tend to be higher than those for hard PZT. The soft PZT/PDMS composite shows better performance as a damper than the hard, PZT composite.

Modeling and characterization of dielectrophoretically structured piezoelectric composites using piezoceramic particle inclusions with high aspect ratios

In this work, the piezoelectric properties at high electric fields of dielectrophoretically aligned PZT—polymer composites containing high aspect ratio particles (such as short fibers) are presented. Polarization and strain as a function of electric field are evaluated. The properties of the composites are compared to those of PZT-polymer composites with equiaxed particles, continuous PZT fiber-polymer composites, and bulk PZT ceramics. From high-field polarization and strain measurements, the effective field dependent permittivity and piezoelectric charge constant in the poling direction are determined for dielectrophoresis structured PZT-polymer composites, continuous PZT fiber-polymer composites, and bulk PZT ceramics. The changes in dielectric properties of the inclusions and the matrix at high fields influence the dielectric and piezoelectric properties of the composites. It is found that the permittivity and piezoelectric charge constants increase towards a maximum at an applied field of around 2.5-5 kV/mm. The electric field at which the maximum occurs depends on the aspect ratio and degree of alignment of the inclusions. Experimental values of d33 at low and high applied fields are compared to a model describing the composites as a continuous polymer matrix containing PZT particles of various aspect ratios arranged into chains. Thickness mode coupling factors were determined from measured impedance data using fitted equivalent circuit model simulations. The relatively high piezoelectric strain constants, voltage constants, and thickness coupling factors indicate that such aligned short fiber composites could be useful as flexible large area transducers.

PVDF Phase Formation and Its Influence on Electrical and Structural Properties of PZT-PVDF Composites

The aim of the study is to find the role of lead zirconate titanate (PZT) in the phase formation of poly vinylidene fluoride (PVDF) and its effect on electrical and structural properties of PZT-PVDF composites (50 Vol%) with 0–3 connectivity. PZT particles of different sizes ranging from micron to nano are used. The particle size (<100 nm) were determined from TEM and the broadening of the characteristic diffraction peaks in the x-ray diffraction (XRD) pattern. Scanning electron microscopy (SEM), studies were performed to analyze the nature of ceramic particle distribution within the matrix. The percentage of polymer crystallinity was determined from differential scanning calorimetry (DSC) and found to decrease with decrease in ceramic particle size. The decrease in the crystallinity percentage is due the hindrance offered by ceramic during the crystallization of the polymer. The melting endotherms of the composites were deconvoluted and the amount of PVDF β-phase present in the composites were determined and was found to decrease with decrease in ceramic particle size. Fourier transform infrared spectroscopy (FTIR) studies were also carried out to confirm the decrease in the β-phase content with decrease in particle size. The variation in the amount of β-phase of the polymer is due to the presence of PZT which acts as a source of electric field during poling and converts other polymer phases to β-phase. The piezoelectric coefficient and remnant polarization was found to decrease with decrease in ceramic particle size and is due to the decrease in percentage of β phase in the composites.

Electrical properties of novel three-phase polymer nanocomposites with a high dielectric constant

Novel three-phase poly(vinylidene fluoride) (PVDF)/lead zirconate titanate (PZT)/expanded graphite (EG) nanocomposites were prepared using the solution method followed by hot pressing. The loading of PZT powder was varied from 0 to 85 wt% (∼57 vol%) in the PVDF matrix. Scanning electron microscopy revealed uniform dispersion of PZT particles in the matrix. X-ray diffraction showed the presence of α-phase of PVDF in the nanocomposites. Dielectric constant of the 80 wt% (C-80) composites increased to approximately 57 and it was further increased to approximately 192, 237 and 842 for the C-80 nanocomposites containing additional EG content of 0.25 wt%, 0.50 wt% and 0.75 wt%, respectively. However, it decreased with increasing frequency. The electrical conductivity and dissipation factor also increased significantly with increasing content of EG. Various theoretical models were used to rationalize the dielectric behaviour of binary composites.

Damping behavior and acoustic performance of polyurethane/lead zirconate titanate ceramic composites

0–3 Type PU-based lead zirconate titanate ceramic (PZT) composites are prepared by in situ polymerization method, this PU/PZT composite material has excellent sound absorption property at low frequencies because of damping property and piezoelectric property. The dispersion of PZT particles in PU matrix, dielectric loss tangent (tanδ), dynamic storage modulus (E′), dynamic loss modulus (E″), and the acoustic absorption coefficient (α) of PU/PZT composites are studied by scanning electron microscopy (SEM), dynamic mechanical analysis (DMA) and two-microphone impedance tube, respectively. The results indicate that the modified PZT particles dispersed well in PU matrix with the content of 30wt%; the tanδ, E′ and E″ are 0.62, 3.75GPa and 6.05GPa, respectively, when the composite with 30wt% of polarizing PZT; the acoustic absorption coefficient is found to increase with an increase of PZT content, and the average acoustic absorption coefficient is 0.32 at low frequencies from 125 to 500Hz.

Electrohydrodynamic atomization deposition of PZT sol–gel slurry and sol infiltration on the films

Abstract This paper reports the use of a deposition technique, called electrohydrodynamic atomization, for producing PZT films from a composite sol–gel slurry. PZT slurries of different powder concentrations were prepared, and then atomization deposition of them was carried out and resultant films examined. It was observed that large splats with well-mixed PZT particles in sol and fine PZT clusters with dry PZT particle agglomeration can be deposited using this technique. In particular, intermediated sol infiltration process on the EHDA deposited film under optimized atomization condition was also studied. It was found that the film with sol infiltration process become more dense and the electrical properties (Pr, ɛr) were improved compared with that without sol infiltration after EHDA deposition.

Characterization of nanostructured ceramics prepared by both high energy ball milling and fast firing sintering processes

High-energy ball milling technique was successfully applied to calcinated lead zirconate titanate (PZT 60/40) powders. After 20 h of ball milling, large PZT particles were completely broken down, reducing its initial size in three orders of magnitude. Experimental results show a huge sinterability enhancement of the PZT powders by using this technique, achieving its maximum sintering rate at ∼800°C. Relatively low densities (∼91%) were achieved in stoichiometric samples, while in 3% lead excess samples sintered at 950°C for 30, 45, 60, 90 and 120 min using a fast firing process and a post-annealing treatment at 800°C for 4 h, densities of ∼97% of the theoretical were achieved. PZT nanostructured ceramics prepared under optimized processing conditions (60 h of powder milling, 950°C of sintering temperature, 60 min of sintering time and a post-annealing process at 800°C during 4 h) show high dielectric constant (ε′) values (900) and low dielectric loss (tan δ) at room temperature and a ferroelectric-paraelectric transition temperature at 375°C.

Lead–Zirconate–Titanate Thick Films by Electrophoretic Deposition for High‐Frequency Ultrasound Transducers

Lead–zirconate–titanate (PZT) thick films for high‐frequency ultrasound applications were fabricated using an electrophoretic deposition (EPD) process. The PZT powder was synthesized from constituent oxides at close‐to‐room temperature by mechanochemical activation followed by calcination at 700°C. Homogeneous PZT thick films with a thickness of ~30 μm and a density of ~80% were produced from ethanol‐based colloidal suspensions containing PZT and PbO particles that were deposited using a constant‐current mode on a platinized alumina substrate and were sintered in the presence of a liquid phase at temperatures compatible with thick‐film technology. The dielectric, mechanical, and piezoelectric parameters of the PZT thick films with a porosity of ~20% were measured and a thickness‐coupling factor of 48% was obtained. Considering that a PZT thick film is a composite structure consisting of PZT and pores, there are several methods that can be applied to calculate the effective parameters where the composite is considered as a piezoelectric homogeneous material. For this study, a matrix method based on a generalization of 2‐2 connectivity was used to deduce the parameters of a completely dense configuration. Our results confirmed that the EPD process is suitable for the fabrication of efficient, high‐frequency transducers operating at frequencies above 40 MHz.

Effects of PZT particle-enhanced ply interfaces on the vibration damping behavior of CFRP composites

In this study, vibration damping behavior of carbon fiber reinforced polymer composites was investigated when ply interfaces were enhanced by lead zirconate titanate (PZT) particles. The influence of particle loading and carbon black coating of particles was analyzed using the dynamic mechanical analysis. When plain PZT particles were distributed in the ply interfaces, the loss factor increased but suddenly dropped with increased particle loading, producing a threshold effect. As the loss factor represents the joule heat of electric current between PZT particles and carbon fibers, the sudden drop implies that there exists incomplete connectivity. To demonstrate the effect of incomplete connectivity, plain PZT particles were coated with carbon black of various weight fraction and the experiments were repeated. The results show there exists an optimal coating ratio of carbon black where the loss factor reaches its maximum value. When the optimal coating was applied to plain PZT particles, the loss factors of composites continuously increased, eliminating the threshold effect.

Study on the preferred orientations of nearly cubic PZT particles synthesized by hydrothermal methods using TiCl 3 reagent

Various parameters such as gel composition, aging, organic additive, and heating method affected the preferred orientation of nearly cubic PZT particles that were prepared by hydrothermal methods using TiCl 3 as a Ti 3+ source, at relatively low temperatures of 100–140 °C. The newly found synthetic conditions could be used to develop specially orientated PZT particles, which may be useful in growing oriented films, for example, by electrophoretic deposition.

SYNTHESIS OF CoFe2O4/Pb(Zr0.53Ti0.47)O3 MULTIFERROIC COMPOSITE THICK FILMS BY LOW-SINTERING-TEMPERATURE SCREEN PRINTING METHOD

CoFe 2 O 4/ Pb ( Zr 0.53 Ti 0.47) O 3 (abbreviated as CFO/PZT) multiferroic composite thick films were successfully fabricated on alumina substrate with gold bottom electrode by screen printing method at a low-sintering temperature. The processing included the modification and dispersion of ferromagnetic CFO powder and ferroelectric PZT powder, the preparation of uniform pastes, and the selection of proper annealing temperature for composite thick films. Transmission electron microscopic pictures (TEM) indicated the submicron meter of particles size for both CFO and PZT particles. After annealing at 900°C for 1 h in air, tape test confirmed the quality of multiferroic thick films as well as pure CFO and PZT films. X-ray diffraction (XRD) showed a coexistence of CFO and PZT phases; furthermore, a smooth surface was observed through scanning electron microscopic (SEM) pictures along with the sharp cross-sectional picture, indicative of 100 μm of film thickness. Ferromagnetic and ferroelectric properties were observed in CFO/PZT films simultaneously at room temperature. Compared with the reported CFO/PZT multiferrroic thin films, the present ferromagnetic property was closing to that of the chemical sol-gel synthesized film and even that from the physical pulsed laser deposition technique. However, the ferroelectric property showed a degenerated behavior, possible reasons for this was discussed and further optimization was also proposed for the potential multifunctional application.