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Polydimethylsiloxane-PbZr <sub/>0.52</sub> Ti <sub/>0.48</sub> O <sub/>3</sub> nanocomposites with high permittivity: Effect of poling and temperature on dielectric properties
摘要： Polydimethylsiloxane (PDMS)/lead zirconate titanate (PbZr0.52Ti0.48O3, PZT)-based nanocomposites with high dielectric constant (permittivity, k) are prepared through room temperature mixing. The effect of PZT loading on electrical and mechanical properties of the PDMS–PZT composites is extensively studied. It is found that there is signi?cant increase in permittivity with PZT loading and decrease in volume resistivity. All the composites have low dielectric loss compared to permittivity value. It is observed that there is increase in permittivity and decrease in volume resistivity of composites after poling, which is due to the dipolar polarization. It is found that both permittivity (ε0) and alternating current conductivity (σ ac) are increased with temperature at low frequency (1 Hz) and decreased with temperature at high frequency (1 MHz). The above composites are sensitive to external pressure and can be used as pressure/force sensor. The tensile strength and % elongation at break decreases with PZT loading, which is due to the nonreinforcing behavior of PZT ceramic. PZT particles distribution and dispersion in PDMS matrix are observed through ?eld emission scanning electron microscopy, high resolution transmission electron microscopy, and atomic force microscopy/scanning probe microscopy. Thermal stability of composites increased with the PZT loading which is due to higher thermal stability of PZT particles compared to PDMS matrix.
关键词： PZT,temperature,permittivity,polydimethylsiloxane,nanocomposite
更新于2025-09-10 09:29:36
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Bulk PZT Cantilever Based MEMS Acoustic Transducer for Cochlear Implant Applications
摘要： This paper presents the first acoustic experimental results of a MEMS based bulk piezoelectric transducer for use in fully implantable cochlear implants (FICI). For this purpose, the transducer was attached onto an acoustically vibrating membrane. Sensing and energy harvesting performances were measured using neural stimulation and rectifier circuits, respectively. The chip has a 150 Hz bandwidth around 1800 Hz resonance frequency that is suitable for mechanical filtering as a sensor. As an energy harvester, bulk piezoelectric transducer generated a rectified power of 16.25 μW with 2.47 VDC with 120 dB-A sound input at 1780 Hz. Among other MEMS acoustic energy harvesters in the literature, reported transducer has the highest power density (1.5 × 10?3 W/cm3) to our knowledge.
关键词： bulk PZT,acoustic energy harvesting,energy harvesting,cochlear implants
更新于2025-09-09 09:28:46
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Performance analysis of fiber reinforced piezoelectric lead zirconate titanate/poly(vinylidene fluoride) composites
摘要： In this paper, the PZT/PVDF composites were prepared by hot-pressing method. The effects of different PZT volume fractions on dielectric, piezoelectric, mechanical and microstructure properties of the composites were investigated. The ratio range of the composites constituent components was determined to enhance mechanical properties. Carbon fiber was used as reinforcing material to enhance the mechanical properties of PZT/PVDF composites. The results showed that PZT/PVDF composites doping with properly carbon fiber had a good compactness, and the relative dielectric constant (εr), the piezoelectric strain constant (d33) and the polarisability were all increased. Finally, the optimal proportion of PZT/PVDF was 50%/50% and carbon fiber content was 0.25%, the d33 of composite increased 14.2%, bending strength increased 7.2% and tensile strength increased 11.5%.
关键词： Tensile Strength,PZT/PVDF,Carbon Fiber,Electrical Properties,Bending Strength
更新于2025-09-09 09:28:46
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Sodium Doping Effect on Optical Permittivity, Band Gap Structure, Nonlinearity and Piezoelectric Properties of PZT Nano-colloids and Nanostructures
摘要： In this research, effects of sodium atoms doping on optical properties of lead zirconate titanate (PZT) nanoparticles (NPs) are studied and compared with undoped particles. Analyses show formations of PZT nanostructures with dimensions below 30 nm. X-ray diffraction patterns show that the particle size increases and the intensity of the preferred direction decreases as the doping sodium atoms are used in the structure. Analyzing absorption spectra of the colloidal solutions shows doped particles are better absorbers at violet-green region of spectra. Also, it has been concluded that PZT NPs only have indirect optical band gap that is narrower for doped particles. Optical permittivity of the ?lms has been compared using a numerical method and shows the prominent effect of doping on real and imaginary parts of permittivity. Also, z-scan experiments have been done to measure thermo-optical and nonlinear absorption coef?cients of the nano-colloids using continue wave Nd-YAG laser illumination. Finally, sodium doping effects on piezoelectric properties of the samples are investigated using a Michelson interferometer.
关键词： z-scan,Piezoelectric,Michelson interferometer,dispersion curve,PZT nanoparticles
更新于2025-09-04 15:30:14
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Piezoelectric Property Enhancement of PZT Thick Film via Pulsed Flash Poling during Sintering
摘要： Lead zirconate titanate (PZT) is a widely used piezoelectric material due to its high piezoelectric response. High temperature thermal sintering and poling are two important steps to obtain a high piezoelectric property PZT film by densifying the film and reorienting the dipoles along the desired direction, respectively. However, these two steps are processed separately, which increases the duration and complexity of the process. Moreover, high temperature process limits the selection of electrode and substrate material to those with very high melting points. This paper experimentally demonstrates the feasibility of processing sintering and poling simultaneously providing a novel approach to prepare PZT film. Moreover, this paper investigates the effect of cyclic temperature excursions above and below the Curie temperature on the piezoelectric properties of PZT thick film. Photonic sintering with high intensity short duration pulsed flashes was used to fuse and merge PZT particles. Simultaneously, electrical poling field (20 kV/cm) was applied through the PZT film to reorient the PZT dipoles. The entire processing duration is less than 5 minutes. The resulted piezoelectric property of the PZT film was analyzed yielding high g33 (22.6 ×10-3 V-m/N), d33 (626 × 10-12 m/V), and permittivity (3130) indicating good sensing and actuating capabilities. This enhanced piezoelectric performance is superior to the groups of PZT films prepared using traditional process. This approach has potential applications for obtaining high performance piezoelectric devices, such as piezoelectric energy harvesters, memories, or bulk acoustic wave resonators.
关键词： piezoelectric,PZT,poling,photonic sintering,additive manufacturing,pulsed flash
更新于2025-09-04 15:30:14
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Study of Pb(Zr <sub/>0.52</sub> Ti <sub/>0.48</sub> )O <sub/>3</sub><scp>MEMS</scp> Piezoelectric Accelerometers for Health Monitoring of Mechanical Motors
摘要： In this study, piezoelectric (PZT) thick films were fabricated on Pt-coated Si substrates by a modified sol-gel method via dispersing the piezoelectric submicron powders of composition (Pb, Sr)Lax(Ti, Zr)1-1/4xO3 (PZT-5A, having a high d33 value of 520 and a high kp value of 0.64) in the PZT sol-gel solution. Then, piezoelectric microelectromechanical system (MEMS) accelerometers were designed and fabricated on Si substrates via micromachining techniques. A mathematic approximation model was firstly proposed. It used an effective thickness of Si membrane to replace the thickness of Si membrane, derived by math theory. The resonant frequency using the mathematic approximation model would be closer to the values of the experimental data than using the original math theory. Finally, the self-made thick film accelerometers with best properties were fabricated via a modified sol-gel method. They had voltage sensitivities in the range of 2.21~2.14mV/g, which is pretty high compared with the reported data, and the resonant frequency is in the range of 6.5~7.1 kHz. In addition, the accelerometers with amplifier circuit and power source were practically used in vibration detection of health monitoring of mechanical motors.
关键词： Piezoelectric thick film,Sol-gel,PZT-5A,MEMS,vacuum infiltration,Accelerometer
更新于2025-09-04 15:30:14