Papers by Keyword: PZT Ceramics

Abstract: Nonlinear dielectric lines have been tested for use in RF generation. Although they have presented a reasonable success in the frequency range between 250 and 400 MHz, their main limitation is the dielectric losses of barium titanate (BT) tiles used as nonlinear medium in these lines, which prevents from achieving higher frequencies. The solution for this appears to be the search for a new dielectric. Herein, we are proposing the use of a piezoelectric titanate-based ceramics known as PZT (lead zirconate titanate), which appears to have lower dielectric losses than BT slabs. In this paper, loss characterization tests of the PZT ceramics are compared with BT in the MHz frequency range. Also, we have investigated and compared the nonlinearity properties of the dielectrics by varying the DC applied voltage and temperature.

Abstract: A piezoelectric hydrophone is design and made with Pb(Zr,Ti)O₃ ceramic. The technology is presented and its impedance characteristics and directivity are researched. Experimental result manifests its usability of the hydrophone.

Abstract: Structured diffuse scattering has been observed in selected area electron diffraction patterns of PbZr1-xTixO3 (PZT). This scattering is most evident in the rhombohedral (Zr-rich) phase but has also been observed for a range of compositions including in the important morphotropic phase boundary (MPB) region as well as in the tetragonal (Ti-rich) phase. Monte Carlo computer simulation has been used to show that the scattering originates from the correlation between the displacements of cations in chains running along all four of the cubic <111>c directions. The transverse polarised nature of the scattering means that the ionic shifts are also directed along <111>c. The results are difficult to reconcile with current structural models for the low temperature phases of PZT. It is conjectured that these phases must still contain significant remnants of the disorder present in the high-temperature paraelectric cubic phase.

Abstract: In present work, lead zirconate titanate (PZT) ceramics, having the composition near morphotropic phase boundary were prepared by conventional mixed oxide method. The sintering process was performed at various sintering temperatures ranging from 1100 to 1300 oC. Relationships between phase and sintering temperature, and phase and structure were reported. An increase sintering temperature affected the increase in grain size. The grain growth rate was found to have a linear fit with the phenomenological kinetic grain growth equation. Tetragonal relative fraction increased with increasing sintering temperature. In addition, dielectric constant at dielectric peak increased with increasing grain size which consistent with the trend of tetragonality.

Abstract: PZT(70/30) powder was prepared by a sol-gel method and PZT thick films were fabricated by the screen-printing method on the alumina substrates. The coating and drying procedure was repeated 4 times. And then the PZT(30/70) precusor solution was spin-coated on the PZT thick films. A concentration of a coating solution was 0.5 mol/L and the number of coating was varied from 0 to 6. The porosity decreased and the grain size increased with increasing the number of coatings. The thickness of the PZT-6(6: number of coatings) films was about 60~65μm. All PZT thick films showed the typical XRD patterns of a typical perovskite polycrystalline structure. The relative dielectric constant of the PZT-6 thick film was 540. The remanent polarization and coercive field of the PZT-6 film were 23.6 μC /cm2, 12.0 kV/cm, respectively.

Abstract: XRD, SEM, bulk density and dielectric properties measurements were used to investigate the effect of TiO2 nanopowder substitution for conventional TiO2 micro-powder on the sintering and electric properties of PZT ceramics. Results revealed that the sintering temperature of dense Pb(Zr0.53Ti0.47)O3 ceramics was lowered about 50°C ~ 100°C when 20% and 40% of conventional TiO2 micro-powder was substituted by TiO2 nanopowder. The electric properties were kept or even enhanced in the PZT ceramics adopted the TiO2 nanopowder.

Abstract: Characteristics during the fracture process of a plate-type piezoelectric composite actuator (PCA) using acoustic emission (AE) monitoring were investigated under a bending load. The fracturing of a monolithic PZT ceramic shows typically brittle behavior; furthermore, the AE signal at the maximum load, which corresponds to the final fracture, has a high amplitude and long duration. Analysis of dominant frequency bands by a fast Fourier transform (FFT) in conjunction with AE parametric analysis expressed the characteristic changes of the fracture process in the PCA. For the PCA, a brittle fracture in a PZT ceramic layer induces the local delamination between the PZT ceramic and adjacent fiber composite layers. Based on the AE analysis and damage observations through optical microscopy, the features of AE associated with fracture process can be elucidated for the PCA.

Abstract: Currently available foot pressure sensors (FPS), which usually include a capacitive sensor and a piezoresistive sensor, tend to exhibit characteristically slow response times. Therefore, we used PZT (lead zirconate-titanate) ceramic in this study, as it responds more quickly than the currently-used materials. We have developed an algorithm which can be applied to the PZT ceramic-based measurement of foot pressure. This algorithm was also verified in experiments. In this study, we fabricated the electronic circuits and a sensor on the basis of the newly-developed algorithm, and then verified the algorithm experimentally.

Abstract: The bottom electrode crystallization (BEC) method was applied to the crystallization of Pb(Zr,Ti)O3 (PZT) thin films deposited by RF magnetron sputtering on Pt/Ti/SiO2/Si substrates. Using a proportional-integral-differential controller, the current flowing in the Pt/Ti films provided accurately controlled Joule heating for the crystallization of the PZT films. The temperature uniformity of the heat treatments was investigated by measuring the ferroelectric properties of PZT. Platinum and tungsten wires were alternatively used as electrical contacts. Scanning electron microscopy (SEM) images were used to inspect the electrical contact regions between the platinum films and different contact wires. The PZT films showed higher remanent polarizations and lower leakage currents near the electrical contacts when Pt wires were used; the ferroelectric properties were more uniform on the PZT films heat-treated with W contact wires. The BEC method can successfully replace the more conventional means for thin film crystallization, having the advantage of being a very precise, low cost and low power consumption technique.