O3 Fibers Research Articles

Nonlinear Magnetoelectric Response of Fe73.5Cu1Nb3Si13.5B9/Piezofiber Composite for a Pulsed Magnetic Field Sensor.

In this paper, we report the nonlinear magnetoelectric response in a homogenous magnetostrictive/piezoelectric laminate material. The proposed magnetoelectric stack Fe73.5Cu1Nb3Si13.5B9/piezofiber is made up of high-permeability magnetostrictive Fe73.5Cu1Nb3Si13.5B9 foils and a piezoelectric Pb(Zr, Ti)O3 fiber composite. The time dependence of magnetoelectric interactions in the Fe73.5Cu1Nb3Si13.5B9/piezofiber structure driven by pulsed magnetic field was investigated in detail. The experimental results show that the magnetoelectric effect is strongly dependent on the external bias magnetic and pulsed magnetic field parameters. To detect the amplitude of a pulsed magnetic field, the output sensitivity reaches 17 mV/Oe, which is excited by a 100 μs width field. In addition, to measure the pulsed width, the output sensitivity reaches 5.4 mV/μs in the range of 0–300 μs. The results show that the proposed Fe73.5Cu1Nb3Si13.5B9/piezofiber sensor is ideally suited for pulsed magnetic field measurement.

Low-Weight 3D Al2 O3 Network as an Artificial Layer to Stabilize Lithium Deposition.

Lithium metal has been regarded as an ideal anode for high-energy-density batteries. However, safety and efficiency concerns still linger due to dendrite formation, reactions between the liquid electrolyte and lithium, high resistance with lithium metal, and the weight of interface layer. A new nanometer-thick, hollow, Al2 O3 fiber network with an elastic and porous 3D structure has been prepared through an atomic-layer deposition process by using cotton sacrificial templates. Through a comparison study of the lithium deposition behavior by employing artificial layers with different structures, the low-weight 3D layer with lithiophilic properties overcomes the issues resulting from the 2D rigid Al2 O3 layer and provides a low overpotential and dendrite-free growth of lithium metal. Moreover, stable lithium deposition enables Li-Li symmetric cells with a 3D artificial layer to be stably cycled 300 times in carbonate-based electrolyte, with superior rate capability, and with a LiNi1/3 Co1/3 Mn1/3 O2 cathode.

Investigation of temperature sensitivity of actuation performance for piezoelectric fiber composites

Piezoelectric fiber composites (PFCs) suffer an extremely wide range of temperatures when used in various aerospace structures where temperature effects on the mechanical properties of PFCs are important. In this paper, the actuation performances of PFCs were studied when they were exposed to environmental temperatures from −15 °C to 80 °C. The results showed that the actuation performance of PFCs was greatly dependent on the environmental temperature. The free strain values and the calculated piezoelectric coefficients d33 and d31 were initially enhanced with the increase of temperature due to the restricted movement of epoxy molecule in the glassy state. The glass transition temperature range of the composite was broadened due to a large number of small pores on the surface of the Pb(Zr,Ti)O3 (PZT) fibers, when the epoxy molecules inside the pores had different transition behaviors compared with those outside the pores. The actuation performance including free strain performance and actuation capability, as well as the piezoelectric coefficients d33 and d31 decreased as the temperature increased above room temperature, since the deformation of epoxy molecules in the viscoelastic state was irreversible.

Enhanced actuation performance of piezoelectric fiber composites induced by incorporated BaTiO3 nanoparticles in epoxy resin

Piezoelectric fiber composites (PFCs) have attracted much interest owing to their flexibility and toughness compared with conventional monolithic piezoceramic wafers. The free strain values and actuation property of PFCs strongly depend on the active electric field applied in Pb(Zr1−xTix)O3 (PZT) fibers. Reducing the dielectric constant mismatch between PZT fiber and the assembling epoxy resin would greatly increase the active electric field in PZT fiber. Therefore, BaTiO3 (BT) nanoparticles were introduced into the epoxy resin to enhance the dielectric constant. Homogeneous dispersion of BT nanoparticles and tight adhesion with the epoxy resin were achieved through a surface modification by dopamine. The maximum dielectric constant of dopamine modified BT/epoxy (BT@Dop/epoxy) nanocomposites was 10.38 with 12 wt% BT@Dop content at 1 kHz. The maximum free strain of PFCs reached 1820 ppm with 6 wt% BT@Dop content, while PFCs assembled by pure epoxy showed 790 ppm at the same processing condition. The tip displacement of cantilever beam actuated by PFCs reached the peak of 19 mm at the resonance frequency with 6 wt% BT@Dop, which was improved by 90% comparing to PFCs with pure epoxy.

Deformation Control During Thermal Treatment of Electrospun PbZr0.52Ti0.48O3 Nanofiber Mats

This paper focuses on the deformation origin of PbZr0.52Ti0.48O3 (PZT) fiber mats obtained by electrospinning. The main cause of deformation of the green mats during heating was found to be a nonuniform relaxation of the stretched PVP polymer, due to nonuniform thermal decomposition of the Pb‐hexanoate in the fibers. This relaxation starts under 100°C, well below the polymer decomposition temperature. The shrinkage was found to accelerate above the polymer glass transition point, giving rise to an overall linear change of almost 50%. The “green” PZT mats were easily separated from the collector by first depositing a pure PVP sublayer on the collector. An optimal fabrication and slow multistep thermal treatment process that provides fiber mats with desired PZT phase and overcomes the nonuniform deformation is described.

Temperature-Dependent Properties of a 1–3 Connectivity Piezoelectric Ceramic–Polymer Composite

Abstract In this work, the 1–3 connectivity piezoelectric ceramic–polymer composites have been fabricated by a viscous-polymer processing, where 0.90Pb(Zr0.52Ti0.48)O3–0.05Pb(Mn1/3Sb2/3)O3–0.05Pb(Zn1/3Nb2/3)O3 (PZT–PMS–PZN) fibers with 0.5 volume fraction were aligned in epoxy matrix. The sintered PZT fibers, with average diameter of 300 μm and aspect ratio (height/diameter) higher than 3, all showed a pure perovskite phase structure and highly dense morphology. The dielectric, piezoelectric, ferroelectric properties and the vibration modes of the 1–3 composites were measured and demonstrated in comparison with that of the monolithic piezoelectric ceramics. The results confirmed that the 1–3 composites possessed a low acoustic impedance (Z) of 13 MRayl and a high thickness coupling coefficient (k t) of 0.59, in addition, only single thickness vibration mode with the resonance frequency over 1.5 MHz was observed. With temperature elevation, the properties including dielectric constant εr , k t, the ratio of k t to k p (k t/k p) and the acoustic impedance (Z) increase, while the planar electromechanical coupling coefficient (k p) show opposite temperature dependence. Under test temperature of 100°C, the 1–3 composites still present excellent temperature stability with increased k t/k p ratio up to 3.6. The researches on temperature-dependent properties of the 1–3 composites are critical for improving its applications in various environments.

Rhombohedral PLZT piezoelectric microfibers: a combined Raman and X-ray diffraction study

A combination of micro- and macro-scale structural characterization methods was implemented for clarification of the influence of different sintering atmospheres on the structural properties of Pb1−xLax(ZryTi1−y)O3 (PLZT) fibers. Three powders, PbZrO3 and ZrO2 (PZ + Z), PbZrO3 (PZ), and PbZrO3 + PbO (PZ + P), were used for the generation of protective atmospheres. Vibrations corresponding to the rhombohedral phase in (Pb0.93La0.07)(Zr0.65Ti0.35)O3 fibers were measured and mapped along the section of the fibers by micro-Raman spectroscopy. Comparison of the Raman data with the evolution of the unit cell parameters indicates that the PZ + Z protective atmosphere ensures the best properties during the PLZT sintering at the temperature of 1250 °C for 6 hours.

A differential magnetoelectric laminated composite for vibration noise suppression

A magnetoelectric (ME) laminated composite made of one pair of piezoelectric Pb(Zr,Ti)O3 (PZT) fiber layers with multiple push–pull polarization units laminated between high-permeability metglas ribbon layers with a differential configuration was proposed for vibration noise suppression. Unlike conventional metglas/PZT fiber/metglas three-layer ME laminated structures, the differential configuration has the capability to reject vibration-induced noise from the magnetic signal. The experiment results showed that the differential ME laminated composite was with up to 30 times enhancement in signal-to-noise ratio.

Piezoelectrically induced mechano-catalytic effect for degradation of dye wastewater through vibrating Pb(Zr0.52Ti0.48)O3 fibers

Hydrothermally synthesized piezoelectric Pb(Zr0.52Ti0.48)O3 fibers were used as a mechano-catalyzer to degrade acid orange 7 dye wastewater via the mechano-catalytic effect, which was achieved as a product of the piezoelectric effect and the electro-catalytic effect. When subjected to mechanical vibration, the Pb(Zr0.52Ti0.48)O3 fibers bend, which in turn induces electric charges on the surfaces of the fibers via the piezoelectric effect. The piezoelectrically induced electric charges induce chemical degradation reactions in the dye wastewater through the electro-catalytic effect. A high mechano-catalytic degradation ratio of ∼80% was achieved for the acid orange 7 solutions (∼30 μmol/l). The piezoelectrically induced mechano-catalytic effect thus provides a highly efficient and reusable technology for dye wastewater degradation applications.

Analysis of composition homogeneity and polarization orientation of PZT submicron fibers by micro-Raman spectroscopy

Micro-Raman spectroscopy is a convenient tool to probe individual objects with a feature size on the submicron scale. The phase, composition, and orientation of Pb(Zr,Ti)O3 fibers fabricated via hydrothermal processing have been characterized by this technique, with the working principles given in the paper. It is shown that the prepared PZT submicron fibers are of a tetragonal pervoskite phase, with Zr/(Zr + Ti) varying from 0.05 to 0.25. The spontaneous polarization has been confirmed to be along the length direction and one of its {1 0 0} planes parallel to the substrate plane.

Fabrication and piezoresponse of electrospun ultra-fine Pb(Zr0.3, Ti0.7)O3 nanofibers

Ultra-fine Pb(Zr0.3, Ti0.7)O3 (PZT) fibers with diameters down to ~100nm have been synthesized by combing the sol-gel method and elecrospinning technique. The as-spun nanoscopic PZT/PVP composite fibers were annealed for 30min at different temperatures, respectively. The morphology and crystalline structure of the sintered Pb(Zr0.3Ti0.7)O3 (PZT) nanofibers were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), micro-Raman spectroscopy. The ferroelectronic and piezoelectric properties of single PZT nanofiber are investigated by using piezoresponse force microscopy (PFM). The results showed that the well crystallized PZT fibers with diameter of ~100nm can achieve a d33 of ~83.4pm/V, which is much larger than that of the reported PZT thin film, and the domain can be successfully switched, with the switch domain polarity of about 180^o. All these show promise for new nanoscale ferroelectronic devices.

Temperature stability and fabrication of Pb(Zn1/3Nb2/3)O3–Pb(Zr,Ti)O3 fibers with Pt core

In order to improve the electrical properties of metal-core piezoelectric ceramic fibers at high temperature, Pb(Zn1/3Nb2/3)O3–Pb(Zr,Ti)O3 piezoelectric ceramics with high Curie temperature were selected. The Pb(Zn1/3Nb2/3) O3–Pb(Zr,Ti)O3 metal-core piezoelectric ceramic fibers were successfully fabricated by extrusion Pb(Zn1/3Nb2/3)O3–Pb(Zr,Ti)O3 powder around a platinum wire. The microstructure and electrical properties of Pb(Zn1/3Nb2/3)O3–Pb(Zr,Ti)O3 ceramics with different calcining and sintering temperatures were investigated. Compared with the previous metal-core piezoelectric ceramic fibers, the Pb(Zn1/3Nb2/3)O3–Pb(Zr,Ti)O3 fibers showed lower piezoelectric and dielectric properties ([Formula: see text], k31 = 0.253, and d31 = −120 pC N−1). However, the Curie temperature of Pb(Zn1/3Nb2/3)O3–Pb(Zr,Ti)O3 ceramics is about 295°C, much higher than that of 0.55Pb(Ni1/3Nb2/3)O3–0.45Pb(Zr0.3Ti0.7)O3 ceramics (110°C). The Pb(Zn1/3Nb2/3)O3–Pb(Zr,Ti)O3 fibers can be used at the highest temperature of 150°C, and the temperature stability of Pb(Zn1/3Nb2/3)O3–Pb(Zr,Ti)O3 fibers is much better than that of 0.55Pb(Ni1/3Nb2/3)O3–0.45Pb(Zr0.3Ti0.7)O3 fibers.

Electric‐field tuning of magnetoelectric properties in Metglas/piezofiber composites

AbstractThe tunability of magnetoelectric (ME) properties by applied dc electric field (E) was systematically investigated for a laminate composite consisting of Metglas, Pb(Zrx Ti1–x)O3 fiber, and interdigitated electrodes. The ME coefficients and equivalent magnetic noise were found to be dependent on E. This dependence is attributed to variations in the magnetic properties. The dielectric properties and noise charge density were relatively invariant to E. A 1.3× improvement in the ME coefficient was obtained at the Villari point under E = 300 V/mm relative to E = 0 V/mm. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Ferroelectric and electromechanical property characterization of single Pb(ZrTi)O3 fiber resonator

Piezoelectric fibers and fiber composites have attracted much attention for anisotropic sensing and actuation applications in recent year. Complete property characterization for piezoelectric fibers is essential for material and device design and fabrication. In this work, ferroelectric and electromechanical properties of single piezoelectric Pb(ZrTi)O3 (PZT) fiber were characterized by polarization–electric field hysteresis loop measurement using single PZT fiber/polymer 1–3 composite approach, and by direct measurement of the complex impedance spectrum of single PZT fiber resonator. A normalized electrical impedance spectrum method developed recently was used to determine the complex piezoelectric, elastic, and dielectric coefficients, mechanical quality factor and electromechanical coefficient from the complex electrical impedance-frequency spectrum measurement. The results were compared with those determined by the IEEE standard method for the pure length extensional resonator. The permittivity of PZT fiber was found larger than PZT bulk materials, which was attributed for the core-shell structure of the fibers.

Electromechanical characterization of 0.55Pb(Ni1∕3Nb2∕3)O3–0.45Pb(Zr0.3Ti0.7)O3 fibers with Pt core

Piezoelectric fibers of composition 0.55Pb(Ni1∕3Nb2∕3)O3–0.45Pb(Zr0.3Ti0.7)O3 were fabricated by extrusion of Pb(Nb,Ni)O3–Pb(Zr,Ti)O3 (PNN–PZT) powder around a platinum wire. Their properties are compared with the same bulk material properties. Fiber’s ceramic component exhibits a d31 of −145pC∕N and a lateral coupling factor of −0.22. The bulk material properties are much higher with a d31 of −404pC∕N and a lateral coupling factor of −0.38. The origin of this discrepancy was investigated by different means: microstructure (grain size and perovskite phase ratio), density, and polarization limitations. The polarization is the main limitation. Due to the radial electric field, a radial polarization gradient is obtained that limits the polarization on the outer edge. The calculation of the expected properties are then found to be k31=−0.28 (homogenization of the properties’ gradient). The remaining discrepancy is then assumed to be due to a density problem that can explain the 30% property loss. Density effect on piezoelectric properties of PNN-PZT bulk ceramics is presented to validate this assumption.

Modeling and Characterization of Piezoelectric Fibers with Metal Core

A simple physical model of the first vibration mode of piezoelectric fibers with a metal core is developed for predicting their properties from the parameters of constituents. It is shown that the metal core diameter influences the piezoelectric properties of the fiber only to a lesser extent for diameter ratios lower than 0.3. The good accuracy of the model is confirmed by finite element modeling (FEM). A characterization procedure for actual fibers is then proposed. The properties of the piezoceramic constituent can be deduced from the fiber behavior, which is a precious tool for checking fiber quality. This procedure is applied to experimental Pb(Nb,Ni)O3–Pb(Zr,Ti)O3 fibers with a platinum core. The actual d31 is -112 pC/N for the ceramic phase of the fiber instead of -246 pC/N for the bulk material. It is believed that the poling process (constraints due to the metal core) and the density optimization are the two key factors for improving these performances.

Synthesis and characterization of micro/nanoscopic Pb(Zr0.52Ti0.48)O3 fibers by electrospinning

Micro/nanoscopic Pb(Zr0.52Ti0.48)O3 fibers were synthesized from commercially available zirconium n-pro-poxide, titanium isopropoxide, and lead 2-ethylhexanoate. Using xylene as a solvent, they were mixed to form a precursor solution with a suitable viscosity for electrospinning. The solution was analyzed using thermo-gravimetric and differential thermal methods. Ultra-fine fibers and mats were electrostatically drawn from the precursor solution. The as-deposited materials were sintered for 2 h at 400, 500, 600, 700 and 800 °C, respectively. Sintered mats or fibers were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Auger electron spectroscopy (AES), Raman micro-spectrometry and scanning-probe microscopy (SPM). The SEM results revealed that the fibers had diameters varying from hundreds of nanometers to 10 μm. Using AES, the elements Pb, Zr, Ti and O, as well as residual C, were detected on the surface of the fibers. Raman and XRD spectra indicated that the precursors began to transform into the intermediate pyrochlore phase at 400 °C, followed by the perovskite Pb(Zr0.52Ti0.48)O3 phase above 600 °C. Scanning-probe microscopy (SPM), operated in the piezo-response imaging mode, revealed spontaneous polarization domains in the fibers, with diameters ranging from 100 to 500 nm.

FTIR Characterization Of PZT Nano Fibers Synthesized from Metallo-organic Compounds Using Electrospinning

ABSTRACTWe have synthesized Pb(Zr0.54Ti0.48)O3 fibers with diameter ranging from 500 nm to several microns using electrospinning and metallo-organics decomposition (MOD) techniques. By a refinement of our electrospinning technique, i.e. by increasing the viscosity of the precursor solution, and by adding a filter to the tip of the syringe, the diameter of synthesized PZT fibers has been reduced to the neighborhood of a hundred nanometers. The complex thermal decomposition was characterized using Fourier-transform infrared (FTIR) spectroscopy and x-ray diffraction (XRD). It was found that alcohol evaporated during electrospinning and that the organic groups had pyrolized before the intermediate pyrochlore phase was formed. There is a good correspondence between XRD and FTIR spectra. It was also found that a thin film of platinum coated on silicon substrate surface not only seems to have catalyzed the phase transformation to PZT but also favored the formation of 110 texture in the synthesized PZT fibers.

Effect of heating temperature on dielectric properties of Pb(Zr,Ti)O3 [PZT] fibers

Ferroelectric Pb(Zr0.53Ti0.47)O3 fibers were reproducibly fabricated by sol-gel technique using triethanolamine (TEA) complexed alkoxide. The phase transition from pyrochlore to perovskite took place about 400°C and a stable single perovskite phase was obtained at 550°C. PZT gel fibers spun through nozzle were heat-treated at 700°C, and at 1000°C for 1 h to certify the effect of heat-treatment temperature on the electrical properties. The PZT fibers had elliptical cross sections with diameter of 72 μm–92 μm, and dense microstructure was obtained by heating at 1000°C. In the PZT fibers heat-treated at 1000°C, a distinguishable relative permittivity peak and a pyroelectric current peak were observed at their Curie temperature. The P-E hysteresis loops of the crystalline PZT fibers were also observed.

Growth and structural characterization of lanthanum doped lead titanate fiber

Lanthanum doped lead titanate Pb1−x Lax Ti1−x/4 O3 fibers (x '0, 5 and 15 at%) were grown by sol-gel technique and characterized for their phase formation behavior and crystal structure. The precursor sol was concentrated upon heating at 100°C to make it spinnable and used for fiber drawing. For heat treatment, a two-step heating schedule was designed on the basis of DSC analysis of the as drawn fibers. X-ray diffraction analysis showed that the tetragonality of the Lead Titanate (PT) fibers reduces with La doping and the structure is changed to pseudocubic from tetragonal. MicroRaman Spectroscopy confirms these observations of change in crystal structure and distortion in the material due to La doping. Dense and elongated grains of about 1 μm diameter were observed at the surface and at the cross section of PT fibers. La doped fibers show a porous fracture surface and also the grain size reduces dramatically with the addition of La. Strain energy is believed to play a major role in the observed changes in the microstructure.