High temperature piezoelectric energy harvester(HTPEH)is an important solution to replace chemical battery to achieve independent power supply of HT wireless sensors.However,simultaneously excellent performances,inclu...High temperature piezoelectric energy harvester(HTPEH)is an important solution to replace chemical battery to achieve independent power supply of HT wireless sensors.However,simultaneously excellent performances,including high figure of merit(FOM),insulation resistivity(ρ)and depolarization temperature(Td)are indispensable but hard to achieve in lead-free piezoceramics,especially operating at 250°C has not been reported before.Herein,well-balanced performances are achieved in BiFeO3–BaTiO3 ceramics via innovative defect engineering with respect to delicate manganese doping.Due to the synergistic effect of enhancing electrostrictive coefficient by polarization configuration optimization,regulating iron ion oxidation state by high valence manganese ion and stabilizing domain orientation by defect dipole,comprehensive excellent electrical performances(Td=340°C,ρ250°C>10^(7)Ωcm and FOM_(250°C)=4905×10^(–15)m^(2)N^(−1))are realized at the solid solubility limit of manganese ions.The HT-PEHs assembled using the rationally designed piezoceramic can allow for fast charging of commercial electrolytic capacitor at 250°C with high energy conversion efficiency(η=11.43%).These characteristics demonstrate that defect engineering tailored BF-BT can satisfy high-end HT-PEHs requirements,paving a new way in developing selfpowered wireless sensors working in HT environments.展开更多
Pb(Mn_(1/3)Sb_(2/3))x(Zn_(1/3)Nb_(2/3))y(Zr_(0.535)Ti_(0.465)),_(1-x-y)O_(3)(PMZN)piezoelectric ceramics were fabricated,The effects of sintering temperature and heat-treatment time on properties wen discussed,the opt...Pb(Mn_(1/3)Sb_(2/3))x(Zn_(1/3)Nb_(2/3))y(Zr_(0.535)Ti_(0.465)),_(1-x-y)O_(3)(PMZN)piezoelectric ceramics were fabricated,The effects of sintering temperature and heat-treatment time on properties wen discussed,the optimum preparation technology parameters were obtained.In this case,the ceramics have the highest electromechanical coupling coefficients and mechanical quality factor and the least dielectric loss.It is revealed that the PMZN piezo-ceramics material can be utilized for high-power ultrasound transducers.展开更多
An exact 3D analysis of free vibration of a piezoceramic hollow sphere submerged in a compressible fluid is presented in this paper. A separation method is adopted to simplify the basic equations for spherically isotr...An exact 3D analysis of free vibration of a piezoceramic hollow sphere submerged in a compressible fluid is presented in this paper. A separation method is adopted to simplify the basic equations for spherically isotropic piezoelasticity. It is shown that there are two independent classes of vibration. The first one is independent of the fluid medium as well as the electric field, while the second is associated with both the fluid parameter and the piezoelectric effect. Exact frequency equations are derived and numerical results are obtained.展开更多
A novel active vibration control technique on the basis of linearized piezoelectric actuators is presented. An experimental apparatus consisting of a cantilever beam to which are attached strain patches and piezoceram...A novel active vibration control technique on the basis of linearized piezoelectric actuators is presented. An experimental apparatus consisting of a cantilever beam to which are attached strain patches and piezoceramic actuators to be used for active vibration suppression is described. A dynamical model of the cantilever beam using Lagrange＇s equation and two coordinate systems are presented. Based on the Lyapunov＇s direct method, an active vibration controller with hysteresis compensation is designed. The controller is designed so that it guarantees the global stability of the overall system. The controller developed is assessed experimentally.展开更多
An experimental study of the response of a piezoceramic actuator set at the throat to a transonic diffuser is carried out by measuring wall static pressure fluctuations and by visualizing the flow field using schliere...An experimental study of the response of a piezoceramic actuator set at the throat to a transonic diffuser is carried out by measuring wall static pressure fluctuations and by visualizing the flow field using schlieren technique. The visualized flow fields are captured with a digital still camera and a digital high speed video camera. The piezo ceramic actuator is attached at the throat of the diffuser and driven by sinusoidal amplified voltage signals. The diffuser used in this experiment is circular arc half nozzle with the height h* and width w of 3 mm and 25 mm, respectively. The blockage factor of the piezoceramic actuator to the diffuser throat is 9.2% assuring the effect of change in the throat area rather than the boundary layer disturbances. The piezoceramic actuator is driven at the frequency of 100 Hz, 200 Hz, and 300 Hz and its amplitude is about 1 mm. It is found that the wall static pressure fluctuations and the behavior of the shock wave clearly correspond to the vibration of the piezo ceramic actuator for all the frequency ranges whereas the averaged shock position remains almost unchanged. All the results mentioned above suggest that driving the piezo ceramic actuator at the diffuser throat can be one of the promising techniques to control unsteady transonic diffuser flow.展开更多
X-ray diffraction and dielectric studies were performed on synthesized ceramic samples of the section(1-x)(0.8PbMg_(1/3)Nb_(2/3)O_(3)·0.2BiScO_(3))・x(0.8PbTiO_(3)-PbMg_(1/3)Nb_(2/3)O_(3))with x=0-1 of the temary ...X-ray diffraction and dielectric studies were performed on synthesized ceramic samples of the section(1-x)(0.8PbMg_(1/3)Nb_(2/3)O_(3)·0.2BiScO_(3))・x(0.8PbTiO_(3)-PbMg_(1/3)Nb_(2/3)O_(3))with x=0-1 of the temary BiScO_(3)-PbTiO_(3)-PbMg_(1/3)Nb_(2/3)O_(3)(BS-PT-PMN)system,including the temperature dependence of thermally stimulated depolarization currents(TSDC).It was found that the samples are solid solutions with a perovskite structure,which have cubic symmetry in the range of x=0-0.587 and tetragonal symmetry in the range of x=0.680-1.In the intermediate composition range of x-0.587-0.680(morphotropic region-MR),the samples consist of a mixture of solid solutions of different symmetries.Data on the change in dielectric properties and TSDC(T)dependencies of solid solutions with a change in their composition were obtained.It was found that samples of compositions x=0-0.625 and 0.6875-1 exhibit relaxor-ferroelectric and conventional ferroelectric properties,respectively,while samples of compositions x=0.625-0.6875combine ferroelectric and relaxor-ferroelectric properties.展开更多
This study investigates the relationship between the electro-mechanical properties of Cu-doped potassium sodium niobate(KNN)piezoceramics driven at high vibration velocities and their structural origins.Intrinsic and ...This study investigates the relationship between the electro-mechanical properties of Cu-doped potassium sodium niobate(KNN)piezoceramics driven at high vibration velocities and their structural origins.Intrinsic and extrinsic contributions to the dynamic strain were quantified at high-power resonance conditions by in-situ high-energy X-ray diffraction.These contributions were correlated to the observed sub-coercive dielectric and piezoelectric responses.Cu doping impairs extrinsic contributions of KNN due to the movement of none180°domains,akin to acceptor-doped hard PZT,reducing the fraction of transverse strain originating from none180°domain wall motion over the total strain of 5%at 0.8 m/s.Therefore,the performance of Cu-doped KNN and PZT were found to be comparable.Both systems exhibit a high mechanical quality factor at low vibration velocity,which decreases at high displacement rates.Additionally,the temperature dependence of electromechanical properties for different Cu doping amounts was investigated.In particular,the mechanical quality factor at the vibration velocity of 1 m/s in a temperature range of-40℃to 140℃was studied.According to thefindings,the composition doped with 0.5%Cu exhibited a stable vibration at 1 m/s,with only 10%variation in the mechanical quality factor between 20C and 140℃.展开更多
This paper studies the relaxation processes and electromechanical hysteresis in relaxor piezoceramics based on the PzT system.Measurements and analysis of the electric displacement and mechanical strain hysteresis loo...This paper studies the relaxation processes and electromechanical hysteresis in relaxor piezoceramics based on the PzT system.Measurements and analysis of the electric displacement and mechanical strain hysteresis loops recorded in bipolar AC electric fields in the frequency range 0.001-5 Hz were performed by means of the electromechanical response characterization system(STEPHV)and program(STEP).It was found that the coercive field,remnant and saturation electric displacement,area of hysteresis loops and relative mechanical strain values are strongly dependent on frequency.As a result of this study,complete sets of parameters characterizing the switching and ferroelectric hysteresis processes in relaxor piezoceramics were obtained.展开更多
In this paper,we present the experimental results of the comprehensive study of the microstructural features and complex dielectric,elastic and electromechanical properties of the ferroelectrically“hard”piezoceramic...In this paper,we present the experimental results of the comprehensive study of the microstructural features and complex dielectric,elastic and electromechanical properties of the ferroelectrically“hard”piezoceramics based on the lead zirconate titanate(PZT)composition.For the measurements and analysis of the real and imaginary parts of the complex parameters of the studied piezoceramics as well as their frequency dependences,we used precision impedance analyzer Agilent 4294A and Piezoelectric Resonance Analysis Program(PRAP)software.We have found that the studied piezoceramics demonstrate a unique combination of dielectric,elastic and electromechanical parameters along with very low elastic and electromechanical losses and dispersion over a wide frequency range and can be used in various high-power ultrasonic applications.展开更多
In this paper,a comprehensive study of microstructure/properties interrelations for porous piezoceramics based on PZT composition was performed.Experimental samples of porous piezoceramics were fabricated using a modi...In this paper,a comprehensive study of microstructure/properties interrelations for porous piezoceramics based on PZT composition was performed.Experimental samples of porous piezoceramics were fabricated using a modified method of burningout a pore former.Porosity dependencies of elastic,dielectric,piezoelectric and electromechanical coefficients of the porous ceramics in the relative porosity range 0-50%were obtained and analyzed.As a result of microstructure analysis,it was found that at any connectivity type(3-0,3-3)and porosity up to 50%the real structures of porous piezoceramics were close to the matrix medium structure with continuous piezoceramic skeleton.It was also revealed that the microstructural features of porous piezoceramics define the character of the dependences of the dielectric,piezoelectric and electromechanical properties of porous piezoelectric ceramics on porosity.In conclusion,microstructure/properties interrelations,as well as new applications of porous piezoceramics were discussed.展开更多
The recent review for the Restriction of Hazardous Substances Directive(RoHS)by the expert committee,appointed by the European Union,stated that the replacement of PZT“…may be scientifically and technologically prac...The recent review for the Restriction of Hazardous Substances Directive(RoHS)by the expert committee,appointed by the European Union,stated that the replacement of PZT“…may be scientifically and technologically practical to a certain degree…”,although replacement“…is scientifically and technically still impractical in the majority of applications.”Thus,two decades of sustained research and development may be approaching fruition,at first limited to a minority of applications.Therefore,it is of paramount importance to assess the viability of lead-free piezoceramics over a broad range of application-relevant properties.These are identified and discussed in turn:1.Cost,2.Reproducibility,3.Mechanical and Thermal Properties,4.Electrical Conductivity,and 5.Lifetime.It is suggested that the worldwide efforts into the development of lead-free piezoceramics now require a broader perspective to bring the work to the next stage of development by supporting implementation into real devices.Guidelines about pertinent research requirements into a wide range of secondary properties,measurement techniques,and salient literature are provided.展开更多
In this review,the evolution of high strain Na_(0.5)Bi_(0.5)TiO_(3)-based lead-free piezoceramics and their multilayer actuators has been explored.First,in terms of Na_(0.5)Bi_(0.5)TiO_(3)-based ceramic materials,the ...In this review,the evolution of high strain Na_(0.5)Bi_(0.5)TiO_(3)-based lead-free piezoceramics and their multilayer actuators has been explored.First,in terms of Na_(0.5)Bi_(0.5)TiO_(3)-based ceramic materials,the origin of high strain,the typical chemical modification methods of obtaining large strain and extrinsic factors affecting the large strain are discussed.Then it briefly summarizes the problems existing in Na_(0.5)Bi_(0.5)TiO_(3)-based ceramics for multilayer actuator applications.Strategies to optimize strain performance by means of microstructure control and phase structure design are also discussed.Thereafter,in terms of multilayer actuator,we describe its characteristics,applications and preparation process systematically,as well as the recent development of Na_(0.5)Bi_(0.5)TiO_(3)-based multilayer actuator.At last,perspectives on directions of following work and promising fields for the applications of the materials and their devices are presented.展开更多
Lead-free piezoceramics based on the(Ba,Ca)(Zr,Ti)O3(BCZT) system exhibit excellent electromechanical properties for low-temperature actuation applications, but suffer from relatively high processing temperatures. Her...Lead-free piezoceramics based on the(Ba,Ca)(Zr,Ti)O3(BCZT) system exhibit excellent electromechanical properties for low-temperature actuation applications, but suffer from relatively high processing temperatures. Here we demonstrate an approach for the reduction of the sintering temperature and simultaneous increase of the electromechanical strain response of(Ba,Ca)(Zr,Ti)O3 piezoceramics by aliovalent doping with Ce. The samples were prepared by solid state synthesis and their crystallographic structure, dielectric, ferroelectric, and electromechanical properties were investigated. The highest d33* value of 1189 pm/V was obtained for the sample with 0.05 mol% Ce, substituted on the A-site of the perovskite lattice. The results indicate a large potential of these materials for off-resonance piezoelectric actuators.展开更多
In this paper,both the ID radial mode and the equivalent circuit of a piezoceramic disk resonator were theoretically analyzed based on IEEE standards.And then,the radial resonance frequency spectra of the PZT-based(Nb...In this paper,both the ID radial mode and the equivalent circuit of a piezoceramic disk resonator were theoretically analyzed based on IEEE standards.And then,the radial resonance frequency spectra of the PZT-based(Nb/Ce co-doped Pb(Zro.s2Ti0.48)O3,abbreviated as PZT-NC)piezoceramic circular disks were measured by an impedance analyzer.A set of resonance frequency spectra including six electrical parameters:Z,R,X,Y,G,and B,were used for making a value distinction between three possible resonance frequencies,and between three possible antiresonance frequencies.A new-form Nyquist diagram was depicted to describe the position relations of these characteristic frequencies.Such a complete resonance frequency spectrum was used to perform the accurate calculation of some material constants and electromechanical coupling parameters for the PZT-NC piezoceramics.Further,the frequency dependence of the AC conductive behavior of the specimen was characterized by the complex impedance measurement.The values of AC conductivity at resonance/antiresonance were deduced from the equivalent circuit parameters.Moreover,the Van Dyke circuit model was assigned to each element contribution and the simulated curves showed a nice fitting with the experimental results.Finally,an additional impedance analysis associated with resonance frequency calculation revealed a complicated coupled vibration mode existing in the annular disk specimen.展开更多
In this paper,a piezoceramic-based wireless sensor network(WSN)was developed for health monitoring of wind turbine blades with active sensing approach.The WSN system has an access point that coordinates the network an...In this paper,a piezoceramic-based wireless sensor network(WSN)was developed for health monitoring of wind turbine blades with active sensing approach.The WSN system has an access point that coordinates the network and connects to a PC to control the wireless nodes.One wireless node functions as an actuator to excite an embedded piezoceramic patch with desired guided waves.The remaining wireless nodes function as sensors to detect and transmit the wave responses at distributed locations.The damage status inside the blade was evaluated through the analysis of the sensor signals.Based on wavelet packet analysis results,a damage index and a damage matrix were developed to evaluate the damage status at different locations.To verify the effectiveness of the proposed approach,a static loading test and a wind tunnel test were performed in the Laboratory of Joint Wind Tunnel and Wave Flume at Harbin Institute of Technology(HIT),China.Experimental results show that damage in wind turbine blades can be detected and evaluated by the proposed approach.展开更多
Low-temperature sintered(Na_(1/2)Bi_(1/2))_(0.935)Ba_(0.065)Ti_(0.975)(Fe_(1/2)Nb_(1/2))_(0.025)O_(3)(NBT-BT-0.025FN)lead-free incipient piezoceramics were investigated using high-purity Li_(2)CO_(3) as sintering aids...Low-temperature sintered(Na_(1/2)Bi_(1/2))_(0.935)Ba_(0.065)Ti_(0.975)(Fe_(1/2)Nb_(1/2))_(0.025)O_(3)(NBT-BT-0.025FN)lead-free incipient piezoceramics were investigated using high-purity Li_(2)CO_(3) as sintering aids.With the ≤0.5 wt%Li_(2)CO_(3) addition,the introduced Li^(+) cations precede to enter the A-sites of the perovskite lattice to compensate for the A-site deficiencies.Once the addition exceeds 0.5 wt%,the excess Lit cations will occupy B-sites and give rise to the generation of oxygen vacancies,which accelerate the mass transport and thus lower the sintering temperature effectively from 1100℃ down to 925℃.It was also found that a small amount of Lit addition has little effect on the phase structure and electromechanical properties of the system,but overweight seriously disturbs these characteristics because of the large lattice distortion.The sintered NBT-BT-0.025FN incipient piezoceramics with 1.25 wt%Li_(2)CO_(3) addition at 925℃ provides a large strain of 0.33% and a corresponding large signal piezoelectric coefficient d_(33)^(*) of 550 pm/V at 60 kV/cm,indicating this system is a very promising candidate for lead-free co-fired multilayer actuator application.展开更多
Ga2O3 was doped into 0.95（K0.48Na0.52）NbO3-0.05LiTaO3 （KNN-LT） cera- mics and its influences on the sintering behavior, phase structure and electrical properties of ceramics were studied. Firstly, SEM observation ...Ga2O3 was doped into 0.95（K0.48Na0.52）NbO3-0.05LiTaO3 （KNN-LT） cera- mics and its influences on the sintering behavior, phase structure and electrical properties of ceramics were studied. Firstly, SEM observation exhibits that more and more glass phase appears in ceramics with the gradual addition of Ga2O3, which determines the continuous decrease in sintering temperatures. And the addition of Ga2O3 is also found to increase the orthorhombic-tetragonal transition temperature （To-T） of system to a higher level. Secondly, both the density and the coercive field （Ec） of ceramics increase firstly and then decrease with increasing the Ga2O3 content, and the KNN-LT-xGa sample at x = 0.004 shows a pinched P-E hysteresis loop. Finally, the impedance characteristics of KNN-LT-xGa ceramics were investigated at different temperatures, revealing a typical vacancy related conduction mechanism. This work demonstrates that Ga2O3 is a good sintering aid for KNN-based ceramics, and the vacancy plays an important role in the sintering and electrical behaviors of ceramics.展开更多
Macro-fiber composite actuators(MFCAs)suffer from strict restrictions on the utilization of lead-containing precursors due to growing environmental concerns.To address this issue,a novel lead-free MFCA based on potass...Macro-fiber composite actuators(MFCAs)suffer from strict restrictions on the utilization of lead-containing precursors due to growing environmental concerns.To address this issue,a novel lead-free MFCA based on potassium sodium niobate piezoceramics has been developed using the dice&fill method.The MFCA demonstrates large electric field-induced displacement(31.4μm over-500-1500 V at 0.5 Hz),excellent frequency stability,and a strong linear relationship between the induced displacement and the external voltage amplitude.Meanwhile,unlike lead-based MFCA that requires superposition of a negative dc bias voltage to pursue higher output performance but risks depolarization,lead-free MFCA can achieve larger displacement by superimposing only a positive bias voltage.This device exhibits excellent reliability,maintaining a stable output over 10^(5) electrical cycles.Additionally,a“back-to-back”coupled MFCA has been developed to regulate bidirectional displacement,making it suitable for various practical applications,including active vibration control.This approach has resulted in a 90%vibration reduction and provides new insights into the design of MFCAs,further facilitating their application in active vibration control systems.展开更多
In this paper,the results of experimental study of dispersion characteristics of complex electromechanical parameters of ferroelectrically“hard”porous piezoceramics based on PZT composition were presented.Experiment...In this paper,the results of experimental study of dispersion characteristics of complex electromechanical parameters of ferroelectrically“hard”porous piezoceramics based on PZT composition were presented.Experimental samples of porous piezoceramics were fabricated using a modified method of burning-out a pore former.The complex constants of porous piezoceramics with relative porosity 16%and their frequency dependences were measured using the piezoelectric resonance analysis method.As a result of experimental studies,regions of elastic,piezoelectric and electromechanical dispersion,characterized by anomalies in the frequency dependences of the imaginary and real parts of the complex constants of porous piezoelectric ceramics were found.It was revealed also that the microstructural features of porous piezoceramics determine the character of frequency dependences of complex electromechanical parameters of porous piezoelectric ceramics.In conclu-sion,the microstructural and physical mechanisms of electromechanical losses and dispersion in porous piezoceramics were discussed.展开更多
0.96(K_(0.5)Na_(0.5-z)Li_(z))(Nb_(0.92)Sb_(0.08))O_(3)-0.04(Ca_(0.5)Sr_(0.5))ZrO_(3)[(KN_(0.5-z)L_(z))NS-CSZ]piezoceramics(0≤z≤0.04)were aligned in the[001]orientation using 3%(in mole)NaNbO_(3)templates with a larg...0.96(K_(0.5)Na_(0.5-z)Li_(z))(Nb_(0.92)Sb_(0.08))O_(3)-0.04(Ca_(0.5)Sr_(0.5))ZrO_(3)[(KN_(0.5-z)L_(z))NS-CSZ]piezoceramics(0≤z≤0.04)were aligned in the[001]orientation using 3%(in mole)NaNbO_(3)templates with a large Lotgering factor(>97%).Their crystal structures transformed from the orthorhombic-pseudocubic(O-P)structure to the orthorhombic-tetragonal-pseudocubic(O-T-P)structure with an increasing z.The P structure was interpreted as a rhombohedral R3m structure.The piezoelectricity of the compositions increased after[001]-texturing,and the enhancement was proportional to the O phase quantity.The composition(z=0.03)exhibited the highest piezoelectric constant(d_(33);670 pC/N)and electromechanical coupling factor(k_(p);0.56).Piezoelectric energy harvesters were produced using the untextured and textured samples(z=0.03).The textured harvester delivered a large power density of 26.6 mW/mm^(3),which was larger than that of the untextured harvester owing to the enhanced kp and d_(33)×g_(33) of the textured piezoceramic.A multilayer actuator was produced using the textured sample(z=0.03),and it exhibited a large acceleration(44.2 G)and displacement(±3,730 mm)at±25 V.Therefore,the[001]-textured(KN_(0.47)L_(0.03))NS-CSZ piezoceramic is suitable for piezoelectric energy harvesters and actuators.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.52272103 and 52072010)Beijing Natural Science Foundation(Grant Nos.2242029 and JL23004).
文摘High temperature piezoelectric energy harvester(HTPEH)is an important solution to replace chemical battery to achieve independent power supply of HT wireless sensors.However,simultaneously excellent performances,including high figure of merit(FOM),insulation resistivity(ρ)and depolarization temperature(Td)are indispensable but hard to achieve in lead-free piezoceramics,especially operating at 250°C has not been reported before.Herein,well-balanced performances are achieved in BiFeO3–BaTiO3 ceramics via innovative defect engineering with respect to delicate manganese doping.Due to the synergistic effect of enhancing electrostrictive coefficient by polarization configuration optimization,regulating iron ion oxidation state by high valence manganese ion and stabilizing domain orientation by defect dipole,comprehensive excellent electrical performances(Td=340°C,ρ250°C>10^(7)Ωcm and FOM_(250°C)=4905×10^(–15)m^(2)N^(−1))are realized at the solid solubility limit of manganese ions.The HT-PEHs assembled using the rationally designed piezoceramic can allow for fast charging of commercial electrolytic capacitor at 250°C with high energy conversion efficiency(η=11.43%).These characteristics demonstrate that defect engineering tailored BF-BT can satisfy high-end HT-PEHs requirements,paving a new way in developing selfpowered wireless sensors working in HT environments.
文摘Pb(Mn_(1/3)Sb_(2/3))x(Zn_(1/3)Nb_(2/3))y(Zr_(0.535)Ti_(0.465)),_(1-x-y)O_(3)(PMZN)piezoelectric ceramics were fabricated,The effects of sintering temperature and heat-treatment time on properties wen discussed,the optimum preparation technology parameters were obtained.In this case,the ceramics have the highest electromechanical coupling coefficients and mechanical quality factor and the least dielectric loss.It is revealed that the PMZN piezo-ceramics material can be utilized for high-power ultrasound transducers.
基金The project supported by the National Natural Science Foundation of China(No.19872060)
文摘An exact 3D analysis of free vibration of a piezoceramic hollow sphere submerged in a compressible fluid is presented in this paper. A separation method is adopted to simplify the basic equations for spherically isotropic piezoelasticity. It is shown that there are two independent classes of vibration. The first one is independent of the fluid medium as well as the electric field, while the second is associated with both the fluid parameter and the piezoelectric effect. Exact frequency equations are derived and numerical results are obtained.
文摘A novel active vibration control technique on the basis of linearized piezoelectric actuators is presented. An experimental apparatus consisting of a cantilever beam to which are attached strain patches and piezoceramic actuators to be used for active vibration suppression is described. A dynamical model of the cantilever beam using Lagrange＇s equation and two coordinate systems are presented. Based on the Lyapunov＇s direct method, an active vibration controller with hysteresis compensation is designed. The controller is designed so that it guarantees the global stability of the overall system. The controller developed is assessed experimentally.
文摘An experimental study of the response of a piezoceramic actuator set at the throat to a transonic diffuser is carried out by measuring wall static pressure fluctuations and by visualizing the flow field using schlieren technique. The visualized flow fields are captured with a digital still camera and a digital high speed video camera. The piezo ceramic actuator is attached at the throat of the diffuser and driven by sinusoidal amplified voltage signals. The diffuser used in this experiment is circular arc half nozzle with the height h* and width w of 3 mm and 25 mm, respectively. The blockage factor of the piezoceramic actuator to the diffuser throat is 9.2% assuring the effect of change in the throat area rather than the boundary layer disturbances. The piezoceramic actuator is driven at the frequency of 100 Hz, 200 Hz, and 300 Hz and its amplitude is about 1 mm. It is found that the wall static pressure fluctuations and the behavior of the shock wave clearly correspond to the vibration of the piezo ceramic actuator for all the frequency ranges whereas the averaged shock position remains almost unchanged. All the results mentioned above suggest that driving the piezo ceramic actuator at the diffuser throat can be one of the promising techniques to control unsteady transonic diffuser flow.
基金support of the Ministry of Education and Science of the Russian Federation as part of the state assignment for creating new youth laboratories(project FSFZ-2022-0007)using equipment of the Collective Usage Center RTU MIREA,which received support from the Ministry of Education and Science of the Russian Federation under Agreement No 075-15-2021-689.
文摘X-ray diffraction and dielectric studies were performed on synthesized ceramic samples of the section(1-x)(0.8PbMg_(1/3)Nb_(2/3)O_(3)·0.2BiScO_(3))・x(0.8PbTiO_(3)-PbMg_(1/3)Nb_(2/3)O_(3))with x=0-1 of the temary BiScO_(3)-PbTiO_(3)-PbMg_(1/3)Nb_(2/3)O_(3)(BS-PT-PMN)system,including the temperature dependence of thermally stimulated depolarization currents(TSDC).It was found that the samples are solid solutions with a perovskite structure,which have cubic symmetry in the range of x=0-0.587 and tetragonal symmetry in the range of x=0.680-1.In the intermediate composition range of x-0.587-0.680(morphotropic region-MR),the samples consist of a mixture of solid solutions of different symmetries.Data on the change in dielectric properties and TSDC(T)dependencies of solid solutions with a change in their composition were obtained.It was found that samples of compositions x=0-0.625 and 0.6875-1 exhibit relaxor-ferroelectric and conventional ferroelectric properties,respectively,while samples of compositions x=0.625-0.6875combine ferroelectric and relaxor-ferroelectric properties.
基金the support of the National Nature Science Foundation of China(No.52325204)We acknowledge DESY(Hamburg,Germany),a member of the HelmholtzGemeinschaft deutscher Forschungszentren(HGF)for the provision of experimental facilities.Parts of this research were carried out at PETRA III(Proposal No.I-20220242)we would like to thank Alexander Schökel for assistance in using the beamline P02.1.
文摘This study investigates the relationship between the electro-mechanical properties of Cu-doped potassium sodium niobate(KNN)piezoceramics driven at high vibration velocities and their structural origins.Intrinsic and extrinsic contributions to the dynamic strain were quantified at high-power resonance conditions by in-situ high-energy X-ray diffraction.These contributions were correlated to the observed sub-coercive dielectric and piezoelectric responses.Cu doping impairs extrinsic contributions of KNN due to the movement of none180°domains,akin to acceptor-doped hard PZT,reducing the fraction of transverse strain originating from none180°domain wall motion over the total strain of 5%at 0.8 m/s.Therefore,the performance of Cu-doped KNN and PZT were found to be comparable.Both systems exhibit a high mechanical quality factor at low vibration velocity,which decreases at high displacement rates.Additionally,the temperature dependence of electromechanical properties for different Cu doping amounts was investigated.In particular,the mechanical quality factor at the vibration velocity of 1 m/s in a temperature range of-40℃to 140℃was studied.According to thefindings,the composition doped with 0.5%Cu exhibited a stable vibration at 1 m/s,with only 10%variation in the mechanical quality factor between 20C and 140℃.
基金financially supported by the Russian Science Foundation Grant No.24-22-00063,https:/rscf.ru/project/24-22-00063/at the Southern Federal University.
文摘This paper studies the relaxation processes and electromechanical hysteresis in relaxor piezoceramics based on the PzT system.Measurements and analysis of the electric displacement and mechanical strain hysteresis loops recorded in bipolar AC electric fields in the frequency range 0.001-5 Hz were performed by means of the electromechanical response characterization system(STEPHV)and program(STEP).It was found that the coercive field,remnant and saturation electric displacement,area of hysteresis loops and relative mechanical strain values are strongly dependent on frequency.As a result of this study,complete sets of parameters characterizing the switching and ferroelectric hysteresis processes in relaxor piezoceramics were obtained.
基金financially supported by the Russian Science Foundation Grant No.24-22-00063,https:/rscf.ru/project/24-22-00063/at the Southern Federal University.
文摘In this paper,we present the experimental results of the comprehensive study of the microstructural features and complex dielectric,elastic and electromechanical properties of the ferroelectrically“hard”piezoceramics based on the lead zirconate titanate(PZT)composition.For the measurements and analysis of the real and imaginary parts of the complex parameters of the studied piezoceramics as well as their frequency dependences,we used precision impedance analyzer Agilent 4294A and Piezoelectric Resonance Analysis Program(PRAP)software.We have found that the studied piezoceramics demonstrate a unique combination of dielectric,elastic and electromechanical parameters along with very low elastic and electromechanical losses and dispersion over a wide frequency range and can be used in various high-power ultrasonic applications.
基金The study was financially supported by the Ministry of Science and Higher Education of the Russian Federation[State task in the field of scientific activity,Scientific Project No.0852-2020-0032(BAS0110/20-3-08IF)].
文摘In this paper,a comprehensive study of microstructure/properties interrelations for porous piezoceramics based on PZT composition was performed.Experimental samples of porous piezoceramics were fabricated using a modified method of burningout a pore former.Porosity dependencies of elastic,dielectric,piezoelectric and electromechanical coefficients of the porous ceramics in the relative porosity range 0-50%were obtained and analyzed.As a result of microstructure analysis,it was found that at any connectivity type(3-0,3-3)and porosity up to 50%the real structures of porous piezoceramics were close to the matrix medium structure with continuous piezoceramic skeleton.It was also revealed that the microstructural features of porous piezoceramics define the character of the dependences of the dielectric,piezoelectric and electromechanical properties of porous piezoelectric ceramics on porosity.In conclusion,microstructure/properties interrelations,as well as new applications of porous piezoceramics were discussed.
文摘The recent review for the Restriction of Hazardous Substances Directive(RoHS)by the expert committee,appointed by the European Union,stated that the replacement of PZT“…may be scientifically and technologically practical to a certain degree…”,although replacement“…is scientifically and technically still impractical in the majority of applications.”Thus,two decades of sustained research and development may be approaching fruition,at first limited to a minority of applications.Therefore,it is of paramount importance to assess the viability of lead-free piezoceramics over a broad range of application-relevant properties.These are identified and discussed in turn:1.Cost,2.Reproducibility,3.Mechanical and Thermal Properties,4.Electrical Conductivity,and 5.Lifetime.It is suggested that the worldwide efforts into the development of lead-free piezoceramics now require a broader perspective to bring the work to the next stage of development by supporting implementation into real devices.Guidelines about pertinent research requirements into a wide range of secondary properties,measurement techniques,and salient literature are provided.
基金the support by the National Natural Science Foundation of China(No.U1732117,51902111 and 51672092)the China Postdoctoral Science Foundation(No.2019M662602)+1 种基金the Open Fund of Guangxi Key Laboratory of Information Materials(No.191015-K)the Donguan Innovative Research Team Program.
文摘In this review,the evolution of high strain Na_(0.5)Bi_(0.5)TiO_(3)-based lead-free piezoceramics and their multilayer actuators has been explored.First,in terms of Na_(0.5)Bi_(0.5)TiO_(3)-based ceramic materials,the origin of high strain,the typical chemical modification methods of obtaining large strain and extrinsic factors affecting the large strain are discussed.Then it briefly summarizes the problems existing in Na_(0.5)Bi_(0.5)TiO_(3)-based ceramics for multilayer actuator applications.Strategies to optimize strain performance by means of microstructure control and phase structure design are also discussed.Thereafter,in terms of multilayer actuator,we describe its characteristics,applications and preparation process systematically,as well as the recent development of Na_(0.5)Bi_(0.5)TiO_(3)-based multilayer actuator.At last,perspectives on directions of following work and promising fields for the applications of the materials and their devices are presented.
基金funded by Ministry of Science,Research and Technology of Iran as a Ph.D.project,with Grant No.481392053,at Materials&Energy Research Center(MERC)supported by Deutsche Forschungsgemeinschaft under the Sonderforschungsbereich 595(SFB 595)fellowship
文摘Lead-free piezoceramics based on the(Ba,Ca)(Zr,Ti)O3(BCZT) system exhibit excellent electromechanical properties for low-temperature actuation applications, but suffer from relatively high processing temperatures. Here we demonstrate an approach for the reduction of the sintering temperature and simultaneous increase of the electromechanical strain response of(Ba,Ca)(Zr,Ti)O3 piezoceramics by aliovalent doping with Ce. The samples were prepared by solid state synthesis and their crystallographic structure, dielectric, ferroelectric, and electromechanical properties were investigated. The highest d33* value of 1189 pm/V was obtained for the sample with 0.05 mol% Ce, substituted on the A-site of the perovskite lattice. The results indicate a large potential of these materials for off-resonance piezoelectric actuators.
基金This work was supported by the China Postdoctoral Science Foundation Funded Project(2017M623025)Special Funding for Post-Doctoral Research Projects from Sichuan Province(2017,presided over by Yu Chen)+1 种基金National Natural Science Foundation of China(Grant No.11702037)Opening Project of Key Laboratory of Inorganic Functional Materials and Devices,Chinese Academy of Sciences(Grant No.KLIFMD201703).
文摘In this paper,both the ID radial mode and the equivalent circuit of a piezoceramic disk resonator were theoretically analyzed based on IEEE standards.And then,the radial resonance frequency spectra of the PZT-based(Nb/Ce co-doped Pb(Zro.s2Ti0.48)O3,abbreviated as PZT-NC)piezoceramic circular disks were measured by an impedance analyzer.A set of resonance frequency spectra including six electrical parameters:Z,R,X,Y,G,and B,were used for making a value distinction between three possible resonance frequencies,and between three possible antiresonance frequencies.A new-form Nyquist diagram was depicted to describe the position relations of these characteristic frequencies.Such a complete resonance frequency spectrum was used to perform the accurate calculation of some material constants and electromechanical coupling parameters for the PZT-NC piezoceramics.Further,the frequency dependence of the AC conductive behavior of the specimen was characterized by the complex impedance measurement.The values of AC conductivity at resonance/antiresonance were deduced from the equivalent circuit parameters.Moreover,the Van Dyke circuit model was assigned to each element contribution and the simulated curves showed a nice fitting with the experimental results.Finally,an additional impedance analysis associated with resonance frequency calculation revealed a complicated coupled vibration mode existing in the annular disk specimen.
基金This research was supported in part by a Texas Higher Education Coordinate Board’s Norman Hackerman Advanced Research Program(NHARP)grant(Contract Number 01980)a US National Science Foundation grant(No.0832089)a US Department of Education GAANN fellowship grant.
文摘In this paper,a piezoceramic-based wireless sensor network(WSN)was developed for health monitoring of wind turbine blades with active sensing approach.The WSN system has an access point that coordinates the network and connects to a PC to control the wireless nodes.One wireless node functions as an actuator to excite an embedded piezoceramic patch with desired guided waves.The remaining wireless nodes function as sensors to detect and transmit the wave responses at distributed locations.The damage status inside the blade was evaluated through the analysis of the sensor signals.Based on wavelet packet analysis results,a damage index and a damage matrix were developed to evaluate the damage status at different locations.To verify the effectiveness of the proposed approach,a static loading test and a wind tunnel test were performed in the Laboratory of Joint Wind Tunnel and Wave Flume at Harbin Institute of Technology(HIT),China.Experimental results show that damage in wind turbine blades can be detected and evaluated by the proposed approach.
基金the generous support by the National Natural Science Foundation of China under grant no.51672092 and U1732117by the Project of Henan Province Science and Technology(Grant No.172102210380)+1 种基金China Postdoctoral Science Foundation funded project no.2018M632847the generous support by Wuhan Morning Light Plan of Youth Science and Technology(No.2017050304010299).
文摘Low-temperature sintered(Na_(1/2)Bi_(1/2))_(0.935)Ba_(0.065)Ti_(0.975)(Fe_(1/2)Nb_(1/2))_(0.025)O_(3)(NBT-BT-0.025FN)lead-free incipient piezoceramics were investigated using high-purity Li_(2)CO_(3) as sintering aids.With the ≤0.5 wt%Li_(2)CO_(3) addition,the introduced Li^(+) cations precede to enter the A-sites of the perovskite lattice to compensate for the A-site deficiencies.Once the addition exceeds 0.5 wt%,the excess Lit cations will occupy B-sites and give rise to the generation of oxygen vacancies,which accelerate the mass transport and thus lower the sintering temperature effectively from 1100℃ down to 925℃.It was also found that a small amount of Lit addition has little effect on the phase structure and electromechanical properties of the system,but overweight seriously disturbs these characteristics because of the large lattice distortion.The sintered NBT-BT-0.025FN incipient piezoceramics with 1.25 wt%Li_(2)CO_(3) addition at 925℃ provides a large strain of 0.33% and a corresponding large signal piezoelectric coefficient d_(33)^(*) of 550 pm/V at 60 kV/cm,indicating this system is a very promising candidate for lead-free co-fired multilayer actuator application.
基金This work was supported by the National Natural Science Foundation of China （Grant No. 51332003）.
文摘Ga2O3 was doped into 0.95（K0.48Na0.52）NbO3-0.05LiTaO3 （KNN-LT） cera- mics and its influences on the sintering behavior, phase structure and electrical properties of ceramics were studied. Firstly, SEM observation exhibits that more and more glass phase appears in ceramics with the gradual addition of Ga2O3, which determines the continuous decrease in sintering temperatures. And the addition of Ga2O3 is also found to increase the orthorhombic-tetragonal transition temperature （To-T） of system to a higher level. Secondly, both the density and the coercive field （Ec） of ceramics increase firstly and then decrease with increasing the Ga2O3 content, and the KNN-LT-xGa sample at x = 0.004 shows a pinched P-E hysteresis loop. Finally, the impedance characteristics of KNN-LT-xGa ceramics were investigated at different temperatures, revealing a typical vacancy related conduction mechanism. This work demonstrates that Ga2O3 is a good sintering aid for KNN-based ceramics, and the vacancy plays an important role in the sintering and electrical behaviors of ceramics.
基金supported by the Basic Research Project of Science and Technology of Shanghai(No.20JC1415000)the National Natural Science Foundation of China(No.52032012).
文摘Macro-fiber composite actuators(MFCAs)suffer from strict restrictions on the utilization of lead-containing precursors due to growing environmental concerns.To address this issue,a novel lead-free MFCA based on potassium sodium niobate piezoceramics has been developed using the dice&fill method.The MFCA demonstrates large electric field-induced displacement(31.4μm over-500-1500 V at 0.5 Hz),excellent frequency stability,and a strong linear relationship between the induced displacement and the external voltage amplitude.Meanwhile,unlike lead-based MFCA that requires superposition of a negative dc bias voltage to pursue higher output performance but risks depolarization,lead-free MFCA can achieve larger displacement by superimposing only a positive bias voltage.This device exhibits excellent reliability,maintaining a stable output over 10^(5) electrical cycles.Additionally,a“back-to-back”coupled MFCA has been developed to regulate bidirectional displacement,making it suitable for various practical applications,including active vibration control.This approach has resulted in a 90%vibration reduction and provides new insights into the design of MFCAs,further facilitating their application in active vibration control systems.
基金The study was financially supported by the Ministry of Science and Higher Education of the Russian Federation[State task in the field of scientific activity,Scientific Project No.0852-2020-0032(BAS0110/20-3-08IF)].
文摘In this paper,the results of experimental study of dispersion characteristics of complex electromechanical parameters of ferroelectrically“hard”porous piezoceramics based on PZT composition were presented.Experimental samples of porous piezoceramics were fabricated using a modified method of burning-out a pore former.The complex constants of porous piezoceramics with relative porosity 16%and their frequency dependences were measured using the piezoelectric resonance analysis method.As a result of experimental studies,regions of elastic,piezoelectric and electromechanical dispersion,characterized by anomalies in the frequency dependences of the imaginary and real parts of the complex constants of porous piezoelectric ceramics were found.It was revealed also that the microstructural features of porous piezoceramics determine the character of frequency dependences of complex electromechanical parameters of porous piezoelectric ceramics.In conclu-sion,the microstructural and physical mechanisms of electromechanical losses and dispersion in porous piezoceramics were discussed.
基金supported by a National Research Foundation(NRF)of Korea grant funded by the Korean government(MSIT)(No.RS-2023-00254689).
文摘0.96(K_(0.5)Na_(0.5-z)Li_(z))(Nb_(0.92)Sb_(0.08))O_(3)-0.04(Ca_(0.5)Sr_(0.5))ZrO_(3)[(KN_(0.5-z)L_(z))NS-CSZ]piezoceramics(0≤z≤0.04)were aligned in the[001]orientation using 3%(in mole)NaNbO_(3)templates with a large Lotgering factor(>97%).Their crystal structures transformed from the orthorhombic-pseudocubic(O-P)structure to the orthorhombic-tetragonal-pseudocubic(O-T-P)structure with an increasing z.The P structure was interpreted as a rhombohedral R3m structure.The piezoelectricity of the compositions increased after[001]-texturing,and the enhancement was proportional to the O phase quantity.The composition(z=0.03)exhibited the highest piezoelectric constant(d_(33);670 pC/N)and electromechanical coupling factor(k_(p);0.56).Piezoelectric energy harvesters were produced using the untextured and textured samples(z=0.03).The textured harvester delivered a large power density of 26.6 mW/mm^(3),which was larger than that of the untextured harvester owing to the enhanced kp and d_(33)×g_(33) of the textured piezoceramic.A multilayer actuator was produced using the textured sample(z=0.03),and it exhibited a large acceleration(44.2 G)and displacement(±3,730 mm)at±25 V.Therefore,the[001]-textured(KN_(0.47)L_(0.03))NS-CSZ piezoceramic is suitable for piezoelectric energy harvesters and actuators.
