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Ferroelectric perovskite (1-x)Pb(Mg 1/3 Nb 2/3 )O 3 -xPbTiO 3 single crystals of near morphotropic phase boundary composition in rhombohedral phase, were successfully grown by a laser heated pedestal growth (LHPG) technique. The LHPG technique is a novel one-dimensional crystal growth method that requires no crucible for growth, allows compositions gradient adjustment during growth, and of high growth speed. The growth of highly volatile Pb-containing perovskite crystals was accomplished by an approach that uses excess PbO and boron oxide in the feed material that act as traveling flux in the molten zone during the growth. Controlling of growth orientation and composition homogeneity was studied. Dielectric, ferroelectric and piezoelectric properties of LHPG grown PMN-PT crystals were obtained and reported in this paper. [ABSTRACT FROM AUTHOR]

A novel 3-0-type composite, that contains ferroelectric (PZT-type) and corundum ceramics, is studied to show features of the piezoelectric response and anisotropy of electromechanical coupling factors. The corundum ceramic is applied as a component with a large elastic stiffness. Almost equal volume fractions of corundum mc and air pores mp are detected at 0.05 < mc < 0.18, and this has no analogies among the studied piezo-active 3-0-type composites. Experimental results on the piezoelectric coefficients , thickness electromechanical coupling factor , planar electromechanical coupling factor , and anisotropy (and ) are interpreted in terms of a model that takes into account features of the composite microgeometry and an interaction between the 3-0 ferroelectric ceramic/corundum and 3-0 ferroelectric ceramic/air regions. The studied 3-0-type composite can be of interest as an active element of piezoelectric transducers, sensors, and other piezotechnical devices. [ABSTRACT FROM AUTHOR]

A piezoelectric performance of a novel 1-0-3 composite based on lead-free single crystals with 4mm symmetry is first analysed. Ferroelectric domain-engineered alkali niobate-tantalate based single crystals provide large values of the piezoelectric coefficients g* 3j and g*h, squared figures of merit d*33g*33 and d*h g*h, and a 0-3 matrix promotes a large piezoelectric anisotropy in specific volume-fraction ranges. An aspect-ratio effect concerned with spheroidal inclusions of a piezoelectric Li2B4O7 single crystal in a polymer medium is studied to show the considerable influence of these inclusions on the effective parameters of the composite. Values of g*33 ~ 103 mV·m / N, g*h ~ (102-103) mV·m / N, d*33 g*33 ~ 10-10 Pa-1, and d*h g*h ~ (10-11-10-10) Pa-1, and the large anisotropy of the piezoelectric coefficients d*3j and electromechanical coupling factors k*3j are achieved in the 1-0-3 composite based on a [001]-poled [Lix(K1-yNay)1-x](Nb1-zTaz)O3:Mn single crystal and make this composite suitable for piezoelectric sensor, energy-harvesting and hydroacoustic applications. [ABSTRACT FROM AUTHOR]

Methods to improve dielectric and piezoelectric properties of ferroelectric ceramics with high Curie temperatures (TC> 700 K) are discussed. In the first method improving the electrophysical properties is achieved due to a change in technology of the synthesis of powders of ferroelectric phases, and a proposed technological mode enables one to keep a composition of these powders due to a decrease of temperature of the synthesis of the chemically active powders and to a decrease of temperature of sintering. In this method high-temperature ferroelectric ceramics based on the Aurivillius phases are characterised by the piezoelectric coefficient d33≤ 40 pС / N and dielectric permittivity ϵT33/ϵ0≤ 230. The second method is concerned with ferroelectric phases of PbTiO3 – PbZrO3 – Bi4Ti3О12 – МеТiO3 (Ме = Са, Sr, Ва), and on this basis ceramics are formed with larger piezoelectric parameters and TC> 700 K. Temperature of the synthesis of powders based on ferroelectric phases, obtained using the low-temperature method, is lower by 430 K on the average, at reducing the process time range by more than 3 times. [ABSTRACT FROM PUBLISHER]

We analyze thickness-shear vibrations of a rectangular plate of quartz piezoelectric crystal for acoustic wave resonator application. The plate is partially electroded in the central region. The scalar differential equation derived by Tiersten and Smythe is employed. Exact solution for the free vibration resonant frequencies and modes are obtained. Trapped modes with vibrations mainly under the electrodes are found. The results are useful to the understanding and design optimization of crystal resonators. [ABSTRACT FROM AUTHOR]

Piezoelectric properties, their anisotropy and sound velocity are first studied in the composite based on ferroelectric ZTS-19 ceramic of the PZT type, and the second component of the composite is piezo-passive clay. The composite as a whole is characterised by a specific porosity and elements of various connectivity patterns. The important role of microgeometric factors in the formation of piezoelectric coefficientsd*3j(j = 1 and 3) and their anisotropy ζd3j=d*33/d*31is discussed in terms of connectivity patterns at the volume fraction of clay 0.01 ≤ mcl≤ 0.35. The role of the clay component and clay-containing thin layers in the formation of the piezoelectric activity and sensitivity is interpreted within the framework of models of the two- and three-component composites based on poled ferroelectric ceramics. Results of modelling are compared to experimental data on the studied composite. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The thickness vibration of piezoceramic ring is investigated by theoretical analysis, numerical simulation, and experimental measurement. Based on the piezoelectric constitutive equations and the hypothesis that a ring has no strain in circumference when vibrating, the thickness vibration mode of ring is treated as a radial longitudinal extended vibration equivalently, the equations was simplified and the resonant frequency of thickness vibration is derived. The resonant frequency is also simulated with finite element software and measured by Impedance Analyzer. Theoretic calculation of resonant frequency is compared with the simulation and measurement. The errors between them are analyzed. [ABSTRACT FROM AUTHOR]

A novel 3 phase (ceramic, epoxy resin and de-coupling material) piezoelectric composite with multi-elements in parallel connection has been developed by using dice-filled technology. The piezoelectric and electromechanical properties of the composite were determined, the resonance uniformity and acoustic coupling between elements in composite were investigated. The results exhibited the piezoelectric coefficient d33 of 400 pC/N, sound velocity of 3100 m/s, acoustic characteristic impedance of 14.3 MPa°s/m, thickness electromechanical coupling coefficient of 0.4, resonance frequency difference between elements was smaller than 0.76%, acoustic attenuation between adjacent element achieved 94%. [ABSTRACT FROM AUTHOR]

Powder compaction and sintering characteristics of the PMN-PT powder prepared by the partial oxalate route have been studied. The PMN-PT powder achieved 60% of theoretical density during compaction by pressing at 100 MPa. The powder compacts were sintered to > 99% TD at 1270°C for 2 hours. Microstructure of the sintered ceramic showed an average grain size of 6.1 μ m. Absence of any pyrochlore phase in the sintered PMN-PT ceramics has been established through XRD analysis. The piezoelectric characteristics of the sintered PMN-PT ceramics have been evaluated. The polarization and strain behaviour of the PMN-PT ceramics has been evaluated and the results are discussed. The PMN-PT ceramics prepared by the partial oxalate route showed d33 (750 pC/N) and kp (0.62.) values higher than that reported for the same prepared by solid state route. [ABSTRACT FROM AUTHOR]

Ba modified (Pb,La,Ag)(Zr,Ti)O3 ceramics synthesized by conventional mixed-oxide method with chemical formula [Pb0.983 - zLa0.012Ag0.005Baz] [(Zr0.52Ti0.48)0.99825]O3 were investigated for ferroelectric and piezoelectric properties. XRD studies indicate that increment of Ba concentration resulted in strong tetragonality in the ceramics. Grain growth (3.08 μ m) inhibited and apparent density (7.54 gm/cm3) enhanced up to 1.5 mole% Ba respectively. As Ba content increased dielectric properties showed maximum values (εRT = 2347, εTc = 23449) while Tc constantly decreased. The remanent (Pr = 34.72 μ C/cm2) and spontaneous polarization (Ps = 41.84 μ C/cm2) were optimum in 1 mole% Ba respectively while Ec showed increasing trend throughout the series. Piezoelectric properties attained maximum values of d33 = 438 pC/N in 1.5 mole% Ba while kp = 0.533 and kt = 0.412 in 1 mole% Ba doped (Pb,La,Ag)(Zr,Ti)O3 ceramics respectively. [ABSTRACT FROM AUTHOR]

Dielectric, ferroelectric and piezoelectric properties of xPb(Mg1/3Nb2/3)O3-(1-x)(Pb0.988 La0.012)(Zr0.535Ti0.465)O3 ceramic system synthesized through columbite precursor method are investigated. X-ray diffraction patterns of ceramics indicated pseudocubic phase formation with pyrochlore phase. Grain growth (4.47 μ m) and apparent density (7.68 gm/cm3) enhanced remarkably in 0.8PMN-0.2PLZT composition, respectively. Increasing PMN content remarkably increased both room temperature dielectric permittivity (εRT = 2316) and dielectric maximum (εTc = 24747) in 0.6PMN-0.4PLZT composition, respectively. PMN substitution in PLZT system enhanced the ferroelectric remanent (Pr = 28.4 μ C/cm2) and spontaneous (Ps = 31.2 μ C/cm2) polarization while coercive field (Ec) continuously decreased in xPMN-(1-x)PLZT system. PMN modification in PLZT system influenced piezoelectric properties (d33, kp and kt) throughout the PMN-PLZT system. [ABSTRACT FROM AUTHOR]

Piezoelectric ceramics Sn2P2S6 was prepared and investigated as potential candidate for hydrophone applications. Their structural and morphological properties were checked by X-ray diffraction and scanning electron microscopy. The set of electromechanical properties was determined using resonance technique. The hydrostatic charge piezoelectric coefficient dh and hydrostatic voltage coefficient gh were measured at the frequency of 100 Hz in an acoustic coupler (pistonphone). It was found that gh and dh*gh coefficients, which are the most important figures of merit for piezoelectrics operating in the hydrostatic regime, in the ceramics studied take values comparable to that of the composites on the basis of Sn2P2S6 and the PZT piezoelectric ceramis. The disadvantage of Sn2P2S6 ceramics is rather high level of the low frequency dielectric losses caused by the hopping conductivity along the grain boundaries.Communicated by Prof. Jan Patzelt [ABSTRACT FROM AUTHOR]

Piezoelectric-hydraulic and electrostrictive-hydraulic actuators producing large displacements are described. They consist of a hollow cylinder made of a polarized piezoelectric ceramics, put in it reservoir, filled by a liquid, and a membrane, moved by the liquid. Of course, gaining the displacement, one loses the force. [ABSTRACT FROM AUTHOR]

Lead zirconate titanate (PZT) ceramics (Zr/Ti = 52/48) have been modified with different quantities of neodymium oxide (Nd2O3). The preparation was carried out via the solid-state-reaction route. The samples were calcined and sintered at 850°C and 1200°C, respectively. The structural evolution and the microstructure were investigated using an X-ray diffractometer (XRD) and a scanning electron microscope (SEM), respectively. The physical properties such as dielectric constants, piezoelectric coefficients, density etc. were also studied. [ABSTRACT FROM AUTHOR]