Papers by Keyword: Lead Zirconate Titanate

Abstract: In this paper, we consider the technological features of the formation of thin ferroelectric films of lead zirconate titanate (PZT) by the method of plasma high-frequency reactive sputtering. The crystal structure, morphology and elemental composition of films deposited on silicon and oxidized silicon substrates are investigated. It is shown that the obtained PZT films have a perovskite structure and are polycrystalline with a predominant crystallite growth in the (110) direction. An automated test bench has been designed and manufactured for measuring the electrophysical parameters of ferroelectric films. The measured CV characteristics of the Ni/PZT/Si structure show the hysteresis caused by the polarization of the PZT film. It is noted that the asymmetry of the dependence of the spontaneous polarization on the applied voltage can be caused by the presence of surface states at the PZT/Si interface.

Abstract: In the present work lead based perovskite ceramic Pb (Zr₀.₅₂Ti _0.38Li_0.1)O₃ was prepared via high planetary mill. The green body was sintered at 850 °C. The effect of 0.1 wt % Li⁺ addition on the sintering temperature, microstructure and on dielectric properties of Pb (Zr_0.52Ti_0.48)O₃ were investigated. Thermal analysis of ceramic reveals that the PZT can be synthesized at low temperature. XRD diffractrogram shows the presence of secondary phase (lead oxide PbO) in the sample. The maximum dielectric constant was observed at low frequency which was 1163.22 at 20 Hz.

Abstract: Processing of piezoelectric linear-array elements for high-frequency linear-array transducers by electrophoretic deposition (EPD) was investigated. Powders with the nominal composition Pb (Zr_0.53Ti_0.47)_0.98Nb_0.02O₃ (PZT Nb) and PbO were stabilised in ethanol by the addition of a polyelectrolyte and mixed together in a molar ratio 98:2. The suspensions of both powders consisted of particles with a median size of 0.2 μm and with a zeta potential of about-50 mV. They were deposited on alumina substrates with patterned gold electrodes at a constant current density. The deposits were sintered at 950°C in a PbO-rich atmosphere. The influence of the inter-electrode distance and the geometry of the counter electrode on the shape and dimensions of the thick films were studied. With the increasing inter-electrode distance the width of the elements decreased and the space between them (kerf) increased. A higher lateral resolution of the elements was obtained when using square-shaped counter-electrode compared to lined-shaped one. When depositing on a substrate with the electrode width of 1 mm and the kerf of 0.5 mm using an inter-electrode distance of 25 mm and a square counter electrode, 20 μm thick PZT Nb elements with a kerf of 360 μm and sharp edge were obtained. When the substrates with the electrode width and kerf of 150 μm were used, the 160 μm wide elements with a kerf of 144 μm were obtained at the same deposition conditions. The results demonstrated that EPD is a suitable technique to process aligned linear-array structures with an element width and a kerf in the order of a few tens of micrometres at optimised deposition conditions.

Abstract: Lead zirconate titanate (PZT) materials are wildly used in aviation, industry and our daily life. Actually, it becomes more and more important to improve its electrical properties. In this paper, the influences of antimony (Sb)-doping and barium (Ba)-doping and sintering temperature upon properties of PZT ceramics have been investigated. The relationships between the microstructure and electrical properties have been analyzed by means of XRD, SEM and impedance analyzer, etc.The XRD patterns indicate that all samples exhibit the tetragonal perovskite structure.This research also suggests that the best sintering temperature is 1190°C if the doping amount of Sb₂O₃ and BaCO₃ are 0.6wt% and 0.2wt% respectively. In this case, the samples possess perfect electrical properties: tanδ=0.02, k_p=66.3%, d₃₃=438pC/N, ε=1740.

Abstract: Nanocrystalline lead zirconate titanate (PZT) powders have been synthesized by solvothermal method, in which a mixed solvent of ethanol and water was used as reactive medium and Pb (NO₃)₂, ZrOCl₂·8H₂O, C₁₆H₃₆O₄Ti, KOH and NH₃·H₂O were used as raw materials. It was found that PZT particle sizes decreased from 2 μm to 100 nm with the ratio of V_ethanol/V_water increasing from 1/2 to 2/1 under a KOH concentration of 4 mol/L at 200 °C for 4 h. It indicated that the V_ethanol/V_water of mixed solvent played an important role in controlling the morphology and size of PZT crystals, as well as reaction temperature.

Abstract: Uniaxial compressive stress was applied during fatigue process of soft lead zirconate titanate piezoelectric ceramics and their fatigue resistance was improved when the stress was larger than 20MPa. Before fatigue, compressive stress had a strong depolarization effect and restricted domains switching behavior under large electric field and domain walls motion under small electric field. However, in a partially fatigued state, while domains switching behavior was still restricted by compressive stress, domain walls motion was enhanced. Removal of the applied stress after partial fatigue induced the remnant polarization restored significantly.

Abstract: 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.

Abstract: 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.

Abstract: Nowadays, the piezoelectric materials are widely used in many areas. The piezoelectric materials will undergo an electrical degradation process during working causes the piezoelectricity and resistance of the piezoelectric materials degrade. The existence of the electrical degradation phenomenon severely limits the applications of the piezoelectric products. During the electrical degradation process, electrical breakdown often occurs and this electrical breakdown has been proposed [1, 2] induces the resistance decrease and local phase changing. In this paper, the electrical breakdown induced current transients are detailed investigated. Three types of current transients are presented and the time durations of current transients are suggested not constant and corresponding to the time duration of the local burn-out process, which is caused by the heat released from the electrical breakdown process.

Abstract: PZT(lead zirconate titanate) piezoelectric thin films were deposited on the glass substrates by RF (radio frequency) magnetron sputtering reaction method. The XRD(X-ray diffraction) analysis is used to characterize the structure of thin film, the pattern of EDS(energy dispersive spectrometer) shows the composition of thin film, and SEM(Scanning Electron Microscopy) is used to study the morphologies of thin films. The influence of different sputter gas content on the crystalline quality and the surface morphology are also investigated. The results demonstrate that volatile of lead oxide is closed to the ratio with the oxide content. The roughness of the thin film is influenced by the crystalline quality.