Showing papers on "Lead zirconate titanate published in 1987"

Effect of dopants on the microstructure and lattice parameters of lead zirconate-titanate ceramics

Abstract: The effect of dopants on the microstructure and lattice parameters of Pb0.94Sr0.06(Zr0.53Ti0.47)O3 ceramics was studied. Small amounts (0 to 0.3 wt%) of Cr2O3, MnO2, Co2O3 and U3O8, were used as dopants. In a few compositions two oxides were used, namely U3O8 with Cr2O3 as well as MnO2 with Cr2O3 X-ray diffraction investigation of powdered samples showed that all the compositions (both modified and unmodified) were of perovskite type with tetragonal symmetry. The Curie temperature was decreased with the decrease of tetragonal distortion indicated by the axial ratio,c0/a0, in all cases. The average grain sizes for the doped and undoped compositions were determined from SEM photomicrographs of polished and acid-etched surfaces using the linear intercept technique. The average grain size for the undoped composition was found to be 10.7μm. The addition of a small amount of dopants controlled the grain growth to give rise to the average grain size of 6.4 to 9.5μm, which appeared to have some effect on the improvement of the piezoelectric properties of the ceramics.

Spatial distributions of polarization and space charge in tin-substituted lead zirconate titanate ceramics using laser intensity modulation method (LIMM)

Abstract: A new method for measuring the spatial distribution of combined polarization and space charge in poled polymer electrets was recently developed. The technique, called the Laser Intensity Modulation Method (LIMM), was modified in the present study in order that it could be used with ferroelectric ceramic samples having thicknesses of the order of 1 mm rather than the tens of micrometers found in conventional polymer films. PZT ceramics with a high Sn content and with compositions close to the Zr phase boundary were studied. The effects of poling conditions on polarization and space charge distributions in the two ferroelectric phases were examined. The polarization distributions were highly nonuniform, being flat in the central regions and diminishing strongly in the regions close to the electrodes. This was true even in samples poled to saturation. Large amounts of space charge were observed in the central regions. Pyroelectric coefficients and spontaneous polarizations were also measured.

Ferroelectric PB(ZR, TI)O3thin films prepared by metal target sputtering

Abstract: Lead zirconate titanate Pb(Zr, Ti)O3 thin films have been deposited by rf magnetron sputtering of a multi-element metal target. The metal target design provided the feasibility for controlling the PZT film composition by adjusting the surface areas of Pb, Zr and Ti at the target. The cubic pyrochlore structure has been obtained on low temperature (100 to 300°C) substrate and a perovskite structure resulted by a post deposition annealing at 600°C. The Pb rich film was found to be a requirement for obtaining the perovskite structure after annealing. The dielectric constants and dielectric losses of perovskite films were from 300 to 500 and from 0.02 to 0.2, respectively. From P–E hysteresis loops, the highest remanent polarization measured was 12.5 µC/cm2 where the corresponding coercive field was 90 kV/cm.

1-3-0 Connectivity piezoelectric composite with void

Abstract: A composite of PZT (lead zirconate titanate) and a compliant polymer having 1-3-0 connectivity is described. A polymer self-connected in all three mutually perpendicular directions with a void in the center has an array of parallel PZT rod elements embedded therein and extending through the void. The void isolates a region of the PZT rods from the polymer. The axes of the PZT rods are along the direction of the poling electric field. Such an arrangement significantly enhances the hydrostatic piezoelectric charge and voltage coefficients dh and gh.

Manufacture of piezoelectric ceramics

Abstract: PURPOSE:To contrive the miaturization and lightening and the improvement in performance by calcining a molded body of ceramics mainly consisting of lead zirconate titanate having a crystal form under Curie temperature while applying a d.c. electric field in a direction that spontaneous polarization is desired to be compounded. CONSTITUTION:Lead zirconate titanate having a tetragonal crystal form under Curie temperature is obtained by weighing and compounding PbO, ZrO2, and TiO2 and grinding them followed by calcination. The calcined substance is ground and a binder is mixed. Then, further grinding is performed and grains are formed. It is put in a die and is pressure-molded to obtain a ceramics molded body 1. Conductive pastes 2, 2 are spread on two planes of the molded body 1 and two metallic plates 3, 3 provided with lead wires 4 hold the both planes. It is put in a crucible 5 and a press board 7 is put on that. The rest space is filled with a dust 8 of the calcined substance and a lid 6 is put on. The molded body 1 is sintered by being put in an electric furnace in a manner the lead wires 4, 4 are projected out of the furnace and a high voltage is flowed in the lead wires to apply a d.c. electric field to the molded body in a direction that spontaneous polarization is desired to be compounded, thereby obtaining piezoelectric ceramics.

Acoustic Characterization of Poling Effects in PZT Ceramics

Abstract: Acoustic velocity and attenuation were measured in poled and unpoled lead zirconate titanate (PZT) ceramics prepared by sintering and hot-pressing under-different conditions. Hot-pressed PZT was found to have attenuation values approximately 1 order of magnitude smaller than simered PZT. For both materials, poling caused a decrease in attenuation. Depolarization and phase transition phenomena were also observed at elevated temperatures using a novel laser-ultrasound technique in combination with conventional pulse-echo measurements.

Fabrication of Transparent PLZT Ceramics with a High Transmittance and Their Application to Optical Light Shutter

Abstract: Lanthamun-modified lead zirconate titanate (PLZT) powders were produced by chemical preparation method and these powders were sintered by ordinal atmosphere sintering method with O2-gas flow. As a result of combination both high quality powder and atmosphere sintering, high transparent PLZT ceramics with a transmittance as high as 67% at the wavelength of 600 nm were obtained. Optical light shutters were produced using these PLZT ceramics and proved to be applicable for commercial use.

Hysteresis behaviour in lead zirconate titanate/polyvinylidene flouride composites

Abstract: Hysteresis phenomena in PZT/PVDF composites for different weight fractions of PZT and PVDF have been measured using a sinusoidal electric field up to 100 kV/cm at 50Hz in the temperature range -20°C to 130°C. Psat and Pr are observed to be increasing with the PZT content in the composite samples. The analysis of the SEM micrographs and the IR spectra suggest that this is because of the structural modification of the composites. The sharp drop in Pr for sample D (90:10) at 80°C is attributed to the depolarization of PVDF.

XPS study of reduction effects in Nb‐doped PZT ceramics

Abstract: Electrical conductivity in lead zirconate titanate ceramic containing niobium oxide as impurity showed a marked increase when it was reduced in hydrogen atmosphere. X-ray photoelectron spectra were used to investigate the chemical behaviour of the reduction products. Depth profiling for reduced Nb-doped PZT indicated the presence of metallic Pb, whereas Zr, Ti and Nb did not exhibit any change in the valency. The amount of PbO showed a marked increase on the surface compared to that of inner layers in the samples. On the basis of the observed results the increase in the electrical conductivity is correlated to the oxygen vacancies produced because of the reduction in hydrogen.

Composite piezoelectric material

Abstract: PURPOSE:To permit characteristics in processability, flexibility, and thermal resistance prevailing in conventional composite type materials to be maintained as they are and piezoelectric constant to be enhanced by causing a thermoplastic resin to be matrixlike and further a carbon black and piezoelectric ceramic powder to be mixed uniformly. CONSTITUTION:A piezoelectric ceramic powder of lead zirconate titanate added at least by one element out of elements such as carbon black, niobium, and strontium is uniformly mixed in a matrix which is composed of one resin at least out of thermoplastic resins comprising high density polyethylene, polypro. pylene, polyvinylidene fluoride, fluoro rubber, polyurethane and the like. This approach permits the material to obtain a higher piezoelectric constant value than those of conventional composite piezoelectric materials and also to furnish larger dimensions and thinner materials than those of conventional ceramics. The material is rich in flexibility and is especially free from fragility or breakage and besides, its excellent processability allows it to be shaped variously depending on applications.

Piezoelectric material for resonance displacement type actuator

Abstract: PURPOSE: To obtain piezoelectric material having satisfactory mechanical quality factor Qm, electromechanical coupling factor Kr, and dielectric loss tanδ, by adding chromium to the bicomponent solid soln. system lead titanate-lead zirconate, or the tricomponent solid soln. system lead zirconate-lead titanate-lead cobaltniobate. CONSTITUTION: The piezoelectric material for resonance displacement type actuator consists of the following (a) or (b). (a) the chromium(Cr) is added to lead zirconate titanate [Pb(Zr, Ti)O 3 ] piezoelectric material. (b) the chromium(Cr) is added to the piezoelectric material consisting of 3 components, lead zirconate(PbZrO 3 ), lead titanate(PbTiO 3 ) and lead cobaltniobate[ Pb(Co 1/3 Nb 2/3 ) O 3 ]. The amt. of chromium to be added is preferably 0.25W0.4wt.% chromium oxide(Cr 2 O 3 ). COPYRIGHT: (C)1989,JPO&Japio

Alternating‐Current‐Assisted Poling of Lead Zirconate Titanate (PZT)

Abstract: A modification of the conventional poling procedure for piezoelectric materials was investigated because of inconsistencies in the literature. Preliminary investigations appeared to support the theory of ac-assisted poling. However, a temperature study/limited duty cycle experiment seemed to indicate that the increase in piezoelectric response was probably due to heat produced by the body in resonance.

Dielectric and piezoelectric studies of La doped PZT polymer composites

Abstract: Lanthanum doped Lead Zirconate Titanate (La:Zr:Ti = 4:51:49) has been shaped to porous three dimensional structures through BURPS (Burntout Plastic spheres) process. The materials are then framed to low-density, low-permittivity 3–3 composites with silicone rubber as the second phase. Poled composite ceramics have shown significant increase in piezo-electric voltage coefficients (g333) with a corresponding drop in dielectric permittivity. Volume fraction of PZT poled is estimated using a theoretical model where the PZT is assumed to be made up of small cubelets of 1 to 2 micrometers in size.

Specimen size-tensile strength relations for a hot-pressed alumina and lead zirconate/titanate

Abstract: Etude fractographique montrant l'augmentation des defauts et la diminution de la resistance lorsque le volume de l'eprouvette augmente

Fine processing method

Abstract: PURPOSE:To subject a substrate having laminated structure to fine working to provide a three-dimensional shape with the flat worked base by laminating and joining thin sheets of plural different materials to form the substrate and successively subjecting each of the above-mentioned thin sheets to laser etching. CONSTITUTION:A thin Al2O3.TiC ceramic sheet 1 which is most easily worked by laser etching is disposed on the uppermost side, a thin lead zirconate titanate (PZT) sheet 2 which is hardly worked by the laser etching next to the above- mentioned sheet is disposed under the same and a thin Al2O3 ceramic sheet 3 which is hardiest to be worked is disposed under the same. These sheets are joined by a heat-resistant adhesive agent to form the substrate having the laminated structure. A laser beam is then scanned to form an aperture 4 to the thin film 1 of the uppermost layer. The output of the laser beam is increased to form an aperture 5 to the thin PZT film 2. The above-mentioned substrate is thereby subjected to fine working to a prescribed shape by laser etching.

Piezoelectric ceramic dynamic microdisplacement compensator

Abstract: The utility model relates to a piezoelectric ceram dynamic micro displacement compensator which belongs to a non electric variable controlling or regulating system. The piezoelectric ceram dynamic micro displacement compensator is formed by stacking piezoelectric ceram sheets made of lead zirconate titanate. Copper foil is not added between sheets, but a 2 to 3 um copper layer is plated in a vacuum ion plating leak process. The static dynamic performance is good, and the linear error of a full range is smaller than 0.6%. The amplitude frequency characteristic is approximate to a horizontal straight line below 500 Hz. In order to compensate and control the machining error in machine tool processing, the utility model provides a compensating measure with good dynamic response to produce a work piece with lower cost, high precision and especially high precision.

Manufacture of composite piezoelectric plate

Abstract: PURPOSE: To efficiently manufacture a product with excellent characteristic by bonding the outer circumference of plural piezoelectric rods by a packing member info a composite piezoelectric substance and cutting off the piezoelectric chip with a prescribed thickness along a plane at a right angle with the axial direction of the rod. CONSTITUTION: Piezoelectric rods 15 made of a lead zirconate titanate are put in a case filled with a packing liquid 10 made of a silicon resin liquid while being arranged. The packing liquid 16 is solidified into a packing member 18 to form the composite piezoelectric substance 17. The composite piezoelectic plate 19 is formed by cutting the composite piezoelectric substance 17 at a plane at a right angle to the axis of the piezoelectric rod 15 so as to obtain a predetermined thickness (t) in response to the frequency of an ultrasonic wave. Plural piezoelectric plates are overlapped and solidified in place of the piezoelectric rods and cut off at a prescribed thickness in a planer direction in crossing with the face-to-face direction. Thus, the composite piezoelectric plate with excellent characteristic is mass-produced with excellent work performance. COPYRIGHT: (C)1989,JPO&Japio

Manufacture of composite sheet

Abstract: PURPOSE:To obtain a composite sheet having high sensitivity, excellent secondary workability by dispersing piezoelectric or pyroelectric sintered particles on a sheet with an adhesive, removing the particles not adhered, immersing liquid insulating polymer among the particles, solidifying the polymer, removing skin layers, forming electrodes on both side surfaces, and polarizing the electrodes. CONSTITUTION:Piezoelectric or pyroelectric sintered material (e.g., sintered material of lead zirconate titanate) is pulverized and screened to form sintered particles 4. A both-side adhesive tape 6 is bonded on one side of an aluminum foil as a carrier 3, and the particles 4 are dispersed. The particles 4 not adhered to the adhesive are removed by fluctuating by elevationally inversely rotating. Gaps among the particles 4 are filled with a binder 1 made of solution of thermosetting resin (e.g., polyamide resin). The foil 3 and the adhesive 6 are separated, to obtain a film 5 on which the particles are dispersed in a single layer. After the film 5 is thermally set, the both sides are polished to expose the particles 4, and thin copper films are formed as electrodes on both side surfaces. A voltage is applied between the electrodes to be polarized to obtain a composite sheet.