Piezoelectric Lead Zirconate Titanate Elements Research Articles

Embedded electrical impedance-based PZT sensor for monitoring hydrating concrete: development and evaluation

The development of an embeddable sensor, which can be placed inside concrete for continuous monitoring of changes in the material brought about by hydration is presented. The embedded sensor relies on monitoring changes in the electrical impedance (EI) measured from a piezoelectric lead zirconate titanate (PZT) patch placed inside hydrating concrete. The EI measurements over a range of frequencies is associated with the dynamic response of the PZT patch with distinct resonant frequencies. The EI of the PZT sensor is reflective of the mechanical impedance to its motion from the surrounding concrete medium. Changes in the EI measurements from an embedded PZT sensor with time relate with the kinetics of cement hydration. The increase in the resonant frequency in the EI spectrum is produced by the increase in the Young’s modulus of the concrete medium. The changes in the resonant conductance amplitude are sensitive to changes in the stiffness of medium associated with a change in the state and the setting behavior of concrete. The role of the epoxy coating provided as protection to the PZT element is to restrict the motion in the early stages of hydration and to allow relative motion of the PZT element when the concrete gains in stiffness. An idealized representation of the embedded PZT sensor is developed for representing the dynamic impedance to its motion from the epoxy and the surrounding concrete medium. The changes in the EI resonant amplitude of an embedded PZT provides a sensitive measure of the setting behavior and early stiffening of the concrete post-setting. The changes in the resonant frequency of the embedded PZT sensor provide a continuous measure of the evolution of stiffness of the concrete throughout the setting and hardening process.

Design and Characterization of High-Density Ultrasonic Transducer Array

This paper is conducted to design, fabricate, and characterize a novel high-density large-scale ultrasonic transducer, which is based on a $64\times 4$ array of 0.753 MHz piezoelectric micromachined ultrasonic transducer (pMUT) with $100~\mu \text{m}$ size and $120~\mu \text{m}$ pitch. The fill factor of the array is 69.4%, which is higher than the other arrays in reports. Sol-gel method with layer-by-layer annealing is used to fabricate isolated piezoelectric lead zirconate titanate elements into a piezoelectric layer. The membrane of the pMUT is released by backside deep silicon etching. The impedance-frequency spectrum of a $4\times 5$ subarray of the transducers is characterized by HP 4294A impedance phase analyzer. As a result, the mean value resonant frequency is 0.753 MHz, in reasonable agreement with COMSOL Multiphysics simulation results. And the array shows good uniformity in resonant frequency. The equivalent circuit of the transducer is extracted from the spectrum and the admittance circle deduced from the circuit is in accordance with experimental data. The results show that the present array has a good application prospect on ultrasonic imaging.

Response of piezoelectric lead zirconate titanate to high-energy xenon ion beam pulse

To develop a new radiation detector, the characteristics of piezoelectric lead zirconate titanate (PZT) are currently being studied using a 400 MeV/n xenon (Xe) beam. In this study, the response of the PZT element to the pulsed beam was investigated by changing the beam intensity. It was found that the time distribution of the Xe ions in the pulse duration must be taken into account to understand the formation of the output signal that appeared on the PZT element.

Variation in resonant frequency of piezoelectric lead–zirconate–titanate element undergoing high-level radiation

A piezoelectric lead–zirconate–titanate (PZT) element was exposed to a 400 MeV/n xenon beam and the radiation effect on the element was studied as a variation of resonant and antiresonant frequencies by the resonance method. A possible effect of heating the element on the resonant frequency was avoided by using data obtained while the temperature of the element was kept constant. Consequently, the variation of the resonant frequency was empirically represented by a simple function of the amount of accumulated energy in the element. We therefore discuss the piezoelectric PZT element as a potential detector for high-level radiation. We point out that a piezoelectric equation including the heat term is required to explain the experimental results.

20615 構造物振動を利用した高出力発電素子に関する研究 : 鉛フリー素子の発電特性(OS7-4【環境と調和したエネルギー利用(4)】)

Electrical power generation devices that use piezoelectric lead zircon ate titanate (PZT) elements have been developed to convert structural vibration energy into electrical energy. However, in recent years, developments of lead-free elements in place of the PZT element have been desired from the point of view of environmental considerations. This paper describes an experimental study to clarify the power generation characteristics of the sodium potassium niobate (KNN) element doped with 0.7mol % lithium as a lead-free element under vibration loads. In the study, power generation characteristics of the KNN element, the PZT element and the PZT element doped with 1.0mol % Nb are compared and evaluated by vibration tests using a vibration power generating equipment From the results, the effects of the magnitude and frequency of the vibration loads on power generation characteristics of the KNN elements and the PZT elements are clarified.

Multimodal characteristics of a piezoelectric lead zirconate titanate element impacted with iron particles having velocities above 20 km/s

The responses of a piezoelectric lead zirconate titanate (PZT) element to hypervelocity collisions were experimentally studied. In this study, the particles of masses ranging from 0.3 to 10 fg were made to collide with PZT at velocities between 20 and 96 km/s. The amplitude and the corresponding rise time of the single-pulse output signals that were produced in the piezoelectric PZT element were measured to determine the possible collision states. The results revealed an apparently multimodal output; three classes were assumed to be involved in the pulse formation mechanism. The amplitude and rise time were sensitive to the collision velocity. The multimodal behavior implied that the PZT-based cosmic dust detectors should be calibrated according to the class they belong to.

Dependence of Thickness of Lead Zirconate Titanate Material Used as Radiation Detector

The characteristics of a radiation detector fabricated with stacks of piezoelectric lead zirconate titanate (PZT) elements were studied by irradiation with a 400 MeV/n xenon (Xe) beam. The detector was designed to monitor the output voltage formed on the surface of each element. Three additional PZT elements were placed in front of the detector to increase the thickness of the PZT target. It seemed that the individual output voltage observed at a position beyond the range was dependent on the amount of strain generated by the ionization loss energy of Xe ions within the range.

Laboratory calibration measurements of a piezoelectric lead zirconate titanate cosmic dust detector at low velocities

A cosmic dust monitor for use onboard a spacecraft is currently being developed using a piezoelectric lead zirconate titanate element (PZT). Its characteristics of the PZT sensor is studied by ground-based laboratory impact experiments using hypervelocity particles supplied by a Van de Graaff accelerator. The output signals obtained from the sensor just after the impact appeared to have a waveform that was explicitly related to the particle’s impact velocity. For velocities less than ∼6 km/s, the signal showed an oscillation pattern and the amplitude was proportional to the momentum of the impacting particle. For higher velocities, the signal gradually changed to a single waveform. The rise time of this single waveform was proportional to the particle’s velocity for velocities above ∼6 km/s. The present paper reports on results for the low velocity case and especially discusses the effect of an outer coating of the sensor with a paint, which is used to reduce heating by solar radiation.

Radiation detector based on piezoelectric lead zirconate titanate material

The feasibility of using piezoelectric lead zirconate titanate (PZT) elements as a radiation detector was examined. We tried to observe the pressure wave excited by irradiating liquid ethanol (C 2H 5OH) with a 400 MeV/n xenon (Xe) beam using an array of PZT elements, while changing the position of beam irradiation. The elements were designed to obtain two independent electric signals in order to estimate the beam position in one direction on a two-dimensional plane. The time at which the peak of the output signal appeared differed between the two signals obtained from one element under limited experimental conditions. This suggests that the trajectory of the Xe beam may be determined in three-dimensional space with an improved array of the PZT elements.

Acoustic signals generated in piezoelectric lead–zirconate–titanate elements by direct bombardment with xenon ions

Acoustic signals were observed with a lead–zirconate–titanate (PZT) element that was directly irradiated with a 368 MeV/n xenon beam. Using an array comprising PZT elements, the energy loss in the PZT was studied. These elements are sensitive to an energy deposit of 100 nJ. A series of values of output voltage vs. integrated thickness of PZT was represented along a line similar to the ionization loss calculated by the Bethe–Bloch formula. The induced voltage was attributed to several processes—ionization, thermal, elastic, and piezoelectric processes. This study describes the possible applications of the PZT element as an active medium for calorimeters and a monitor for hypervelocity impact of space dust.

Response of acoustic signals generated in water by energetic xenon ions

The acoustic signals generated by bombarding 400 MeV/n xenon ions in water were studied using an array of piezoelectric lead–zirconate–titanate elements. The observed signal was reduced to a bipolar form through Fourier analysis. The output voltage corresponded to the amount of energy deposit in water, and it tailed off beyond the range of 400 MeV/n xenon in water. This magnitude was explained qualitatively as cumulative processes. Its behavior was consistent with the calculations based on the Bethe–Bloch formula. Possible applications of this detector to radiology and heavily doped radiation detectors are described.