Titanate Fibers Research Articles

Effect of potassium titanate fibres and metal sulphides in the tribological behaviour of brake friction composites

In a brake system, brake friction composites are essential for converting kinetic energy into frictional heat. An optimal brake friction composite should ensure a stable coefficient of friction under extreme operational conditions. This study examines the tribological performance of brake friction composites incorporating potassium titanate fibres and metal sulphide lubricants in standard brake pad formulation. Brake friction composites were engineered by varying the potassium titanate fibre content from 10 to 30 %, while the lubricant mixture (comprising graphite, MoS2, Bi2S3 and Sb2O3) was proportionally adjusted from 27 to 7 %, with the filler and binder concentrations held constant throughout the formulation. The phenolic resin-based composites were characterised for their physical, chemical and mechanical properties in accordance with the IS 2742 (Part 4) standard. The tribological performance of the fabricated composites was evaluated using a rotating drum setup, following the SAE J661 procedure. The worn surfaces of the samples were analysed to identify wear mechanisms utilising scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). The results demonstrated that the optimal combination of potassium titanate fibres and metal sulphide lubricants significantly influences wear resistance and friction stability, with varying degrees of primary and secondary plateau formation observed. This comprehensive characterisation provides valuable insights into the material's behaviour under operational conditions, guiding the development of advanced brake friction composites.

Enhanced Piezoelectric Properties of Poly(Vinylidene Fluoride)/Lead Zirconate Titanate (PVDF/PZT) Fiber Films Fabricated by Electrospinning

Enhanced Piezoelectric Properties of Poly(Vinylidene Fluoride)/Lead Zirconate Titanate (PVDF/PZT) Fiber Films Fabricated by Electrospinning

Fast wavelength-swept polarization maintaining all-fiber mode-locked laser based on a piezo-stretched fiber Lyot filter.

We demonstrate for the first time a strain-controlled all polarization-maintaining (PM) fiber Lyot filter based on a piezoelectric lead zirconate titanate (PZT) fiber stretcher. This filter is implemented in an all-PM mode-locked fiber laser to serve as a novel wavelength-tuning mechanism for fast wavelength sweeping. The center wavelength of the output laser can be tuned across a range from 1540 nm to 1567 nm linearly. And the strain sensitivity achieved in the proposed all-PM fiber Lyot filter is 0.052nm/με, which is 43 times higher than that achievable by other strain-controlled filters such as a fiber Bragg grating filter (0.0012nm/με). Wavelength-swept rates up to 500 Hz and wavelength tuning speeds up to 13,000 nm/s are demonstrated, which is hundreds of times faster than what is attainable with conventional sub-picosecond mode-locked lasers based on mechanical tuning methods. This highly repeatable and swift wavelength-tunable all-PM fiber mode-locked laser is a promising source for applications requiring fast wavelength tunability, such as coherent Raman microscopy.

Electrochemical Activation Applied to Perovskite Titanate Fibers to Yield Supported Alloy Nanoparticles for Electrocatalytic Application.

Active bi-metallic nanoparticles are of key importance in catalysis and renewable energy. Here, the in situ formation of bi-metallic nanoparticles is investigated by exsolution on 200nm diameter perovskite fibers. The B-site co-doped perovskite fibers display a high degree of exsolution, decorated with NiCo or Ni3 Fe bi-metallic nanoparticles with average diameter about 29 and 35nm, respectively. The perovskite fibers are utilized as cathode materials in pure CO2 electrolysis cells due to their redox stability in the CO/CO2 atmosphere. After in situ electrochemical switching, the nanoparticles exsolved from the perovskite fiber demonstrate an enhanced performance in pure CO2 electrolysis. At 900°C, the current density of solid oxide electrolysis cell (SOEC) with 200µm YSZ electrolyte supported NiFe doped perovskite fiber anode reaches 0.75Acm-2 at 1.6V superior to the NiCo doped perovskite fiber anode (about 1.5 times) in pure CO2 . According to DFT calculations (PBE-D3 level) the superior CO2 conversion on NiFe compared to NiCo bi-metallic species is related to an enhanced driving force for C-O cleavage under formation of CO chemisorbed on the nanoparticle and a reduced binding energy of CO required to release this product.

Ferroelectric Ceramic Materials Prepared by Nanoparticles in Outdoor Environmental Sculpture Art

With the development and progress of the city, people’s research on outdoor sculpture has gone deeper, and the field of material research has been raised to the field of spiritual culture. Tang Sancai is beautiful in color and wonderful in shape, such that when ceramics are used in outdoor environmental sculpture art, except for its performance, its appearance and tone must also be taken into consideration. Even when ferroelectric ceramics are used in outdoor sculptures, changing their shapes and taking into account their colors can be done invisibly only by passing through an electromagnetic field. Ferroelectric ceramics are generally divided into insulating, dielectric, piezoelectric, magnetic, semiconductor, transparent, and infrared sensor ceramics. This article integrates the manufacturing method of ferroelectric ceramics into outdoor environmental sculpture art. First of all, this article describes the ferroelectric ceramics and outdoor environmental sculptures, explains the method of preparing ferroelectric ceramics from barium titanate nanoparticles, and explains the pyroelectric inverse process of the electric card effect principle of electric ceramic materials, the thermodynamics of Maxwell’s relationship, and the thermodynamics of Landau’s phenomenological theory. The elasticity of the system is calculated, and the preparation of tetragonal barium titanate ferroelectric ceramics prepared by hydrothermal nanoparticles and SBT/Cu ferroelectric ceramic composites prepared by nanoparticle metallurgy is explained. In the plasma discharge mode, the optimal temperature for sintering the composite material is obtained. Then through experiments, research on the preparation and performance of the high dielectric constant BTnf-Ag/PVDF ferroelectric ceramic nanocomposite and its application in environmental sculptures are demonstrated. Compared with the two ancient BTnf/PVDF composite materials, the barium titanate fiber prepared by electrostatic spinning shows that the BTnf-Ag/PVDF composite material has a higher dielectric constant, and the dielectric loss is not too high. The 41.8vol% BTnf-Ag composite material has a dielectric constant of 82.6BTnf/PVDF, but the composite material’s dielectric constant is only 62.4, an increase of 32%. The dielectric loss of the 41.8vol% BTnf-Ag composite material is 0.053, and the dielectric loss constant of the BTnf/PVDF composite material is 0.049; the dielectric loss is reduced by 8% year-on-year. Ferroelectric ceramic composites prepared by adding silver ions have ideal dielectric properties and enhanced energy storage density.

Anisotropic magnetoelectric effect in lead zirconate titanate and magnetostrictive fiber composite structures

Objectives. The development of composite structures in which a strongly anisotropic magnetoelectric (ME) effect is observed is relevant for the creation of sensors that are sensitive to the direction of the magnetic field. Such an ME effect can arise due to the anisotropy of both the magnetic and the piezoelectric layers. In this work, a new anisotropic material named as a magnetostrictive fiber composite (MFC), comprising a set of nickel wires placed closely parallel to each other in one layer and immersed in a polymer matrix, is manufactured and studied. The study aimed to investigate the linear ME effect in a structure comprising of a new magnetic material, MFC, and lead zirconate titanate (PZT-19).Methods. The magnetostriction for the MFC structure was measured using the strain-gauge method; the ME effect was determined by low-frequency magnetic field modulation.Results. Structures with nickel wire diameters of 100, 150, and 200 μm were fabricated. The MFC magnetostriction field dependences were determined along with the frequency-, field-, and amplitude dependences of the ME voltage in the case of linear ME effect. Measurements were carried out at various values of the angle between the direction of the magnetic field and the wires. All samples demonstrated strong anisotropy with respect to the direction of the magnetic field. When the magnetic field orientation changes from parallel to perpendicular with respect to the nickel wire axes, the ME voltage decreases from its maximum value to zero.Conclusions. The largest ME coefficient 1.71 V/(Oe · cm) was obtained for a structure made of MFC with a wire diameter of 150 μm. With increasing wire diameter, the resonance frequency increases from 3.5 to 6.5 kHz. The magnetostriction of the MFC is comparable in magnitude to that of a nickel plate having the same thickness.

Influence of resorcinol–formaldehyde resin on the formation of alkali titanate fibers

Nowadays, alkali titanate (ATO) fibers are attracting attention because they can provide a reinforcing as well as a functional effect. In this study, ATO fibers were synthesized by a one-step calcination route without specialized equipment and flux using a resorcinol–formaldehyde (RF) resin. Homogeneous mixing of the RF resin dissolved in water, TiO 2 , and an alkali source led to a uniform dispersion, and the three-dimensional polymerized RF resin formed a closely structured matrix with TiO 2 and the alkali source. By carbonizing the RF resins prepared using K or Na as the alkali source, titanate fibers with lengths greater than 1 mm were formed. Growth mechanisms and crystal structures of the titanate fibers synthesized with and without the RF resin were completely different. Effects of the RF resin on the crystal structure and morphology of the titanate fibers were systematically studied by changing the calcination temperature and molar ratio of TiO 2 and alkali source (Li, Na, or K). We found that the RF resin played an essential role in producing a suitable reaction field for fiber growth and controlling the morphology of titanate fibers. • Titanate fibers can be easily synthesized by a one-step calcination process. • Resorcinol-formaldehyde (RF) resin was applied as a carbon source. • RF resin gives significant effects on the growth mechanisms of the fiber. • The surface exposed by the decomposition of RFC acts as a reaction field. • The exposed surface is also important for uniform fiber formation.

Preparation of Graphene Oxide/La2Ti2O7 Composites with Enhanced Electrochemical Performances for Supercapacitors.

A series of graphene oxide (GO)/lanthanum titanate (La2Ti2O7, LTO) fiber composites were prepared through a hydrothermal method. The LTO fibers were homogeneously dispersed between the GO sheets. The structure and micromorphology of the GO/LTO composites were systematically studied. The composite exhibited a high specific capacitance of 900.6 F g–1 at a current density of 1 A g–1 in the 1 M H2SO4 and 10 wt % sucrose aqueous solution as the electrolyte. With the extended potential window of 1.8 V, the fabricated asymmetric supercapacitor device delivered a maximum energy density of 94.0 Wh kg–1 at a power density of 750.1 W kg–1. The GO/LTO composites could be promising materials for energy storage.

A trilogy antimicrobial strategy for multiple infections of orthopedic implants throughout their life cycle

Bacteria-associated infection represents one of the major threats for orthopedic implants failure during their life cycles. However, ordinary antimicrobial treatments usually failed to combat multiple waves of infections during arthroplasty and prosthesis revisions etc. As these incidents could easily introduce new microbial pathogens in/onto the implants. Herein, we demonstrate that an antimicrobial trilogy strategy incorporating a sophisticated multilayered coating system leveraging multiple ion exchange mechanisms and fine nanotopography tuning, could effectively eradicate bacterial infection at various stages of implantation. Early stage bacteriostatic effect was realized via nano-topological structure of top mineral coating. Antibacterial effect at intermediate stage was mediated by sustained release of zinc ions from doped CaP coating. Strong antibacterial potency was validated at 4 weeks post implantation via an implanted model in vivo. Finally, the underlying zinc titanate fiber network enabled a long-term contact and release effect of residual zinc, which maintained a strong antibacterial ability against both Staphylococcus aureus and Escherichia coli even after the removal of top layer coating. Moreover, sustained release of Sr2+ and Zn2+ during CaP coating degradation substantially promoted implant osseointegration even under an infectious environment by showing more peri-implant new bone formation and substantially improved bone-implant bonding strength.

Photocatalytic Reduction of CO<sub>2</sub> over Metal/BaTiO<sub>3</sub> Catalysts

The paper presents the results of experimental studies of a photoactive catalyst in the form of barium titanate fibers with deposited particles of nickel, platinum and gold. Barium titanate fibers were synthesized by the molten salt method. The obtained barium titanate fibers were studied by SEM, TEM, XRD, and Raman spectroscopy. Photocatalytic studies showed that barium titanate fibers with platinum nanoparticles are the most active of the three prepared Metal/BaTiO3 samples.

Microwave absorption study of composites based on CQD@BaTiO3 core shell and BaFe12O19 nanoparticles

A novel microwave absorbing composite medium for X-band (8 GHz–12GHz) is developed by mixing of core-shell consisting of carbon quantum dots (CQDs) coated barium titanate (BaTiO3) fibers with barium hexaferrite (BaFe12O19) nanoparticles. CQDs are synthesized from agricultural waste using lemon peel as precursor material while the low density BaTiO3 fibers are synthesized via electro-spinning technique. The increase in diameter of BaTiO3 fibers as an effect of CQD coating has been confirmed using FESEM technique. The XRD and FTIR analysis of CQD coated BaTiO3 fibers are used to confirm the presence of carbon along with barium titanate. Composites based on BaFe12O19 nanoparticles and CQD coated barium titanate (CQD@BaTiO3) fibers were developed by the ball-milling of BaFe12O19 nanoparticles with CQD@BaTiO3 in different weight concentrations. The improved electrical permittivity of the BaFe12O19 and CQD@BaTiO3 composites resulted in the increased reflection loss due to better impedance matching with the free space. The maximum reflection loss of −25.38 dB was achieved for composite containing 85% of BaFe12O19 and 15% of CQD@BaTiO3, for a pellet of thickness 2.75 mm. Also, the maximum −10dB bandwidth (90% absorption) of the composite reaches to 2.7 GHz.

A mesoporous catalytic fiber architecture decorated by exsolved nanoparticles for reversible solid oxide cells

Along the way to developing highly active catalysts, the fabrication of unique architectures is significant in determining the performance of energy conversion and storage devices. One of the highly competitive options is surface-modified with dispersed nanoparticles by an simply in-situ growth strategy. Typically, the exsolution of active nanoparticles is demonstrated in the irregular powders of perovskite oxides. Here, we report the rational design and fabrication of a porous A-site-deficient titanate fiber decorated by exsolved Ni nanoparticles as a highly efficient and robust fuel electrode for solid oxide cells. We find that the porosity of fiber is one of the pronounced effects on the Ni exsolution. Based on the finite element simulation method and experiments, it is demonstrated that the addition of Gd0.1Ce0.9O2 (GDC) in fibrous fuel electrode enhances the contact and connectivity between fibers. This unique microstructure not only provides high specific surface area and more active sites but also benefits to easier mass transfer and charge transfer, resulting in a much lower polarization resistance. The corresponding device shows superior electrochemical performance and durability in humified H2 (3% H2O). This highly active and robust fuel electrode together with the unique architectures lays a strong foundation for designing high-electrochemical active devices.

Low-temperature preparation of novel stabilized aluminum titanate ceramic fibers via nonhydrolytic sol-gel method through linear self-assembly of precursors

Stabilized aluminum titanate fibers were prepared via nonhydrolytic sol-gel (NHSG) method through linear self-assembly of precursors. The results show that NHSG method generates the heterogeneous condensation with the formation of Al–O–Ti, Mg–O–Ti, Fe–O–Ti, Mg–O–Al, Fe–O–Ti bonds, which ensures that magnesium ions and iron ions can enter aluminium titanate lattice and stabilize it at 750 °C. Bimolecular associated structure of chlorotitanium ethoxide titanium precursor promotes the self-linear-assemble of all precursors, which enables the excellent spinnability of sol. Stabilized aluminum titanate fibers have excellent corrosion resistance. The thermal expansion coefficient of stabilized aluminum titanate ceramic is −0.142 × 10−6°C−1.

Influence of dispersed phase morphology on electrical and fatigue properties of BaTiO3/PDMS nanogenerator

A flexible piezoelectric nanogenerator (FPENG) was fabricated by incorporating barium titanate (BT) fibers and BT powders into polydimethylsiloxane (PDMS) matrix phase, also with an interdigital electrodes (IDEs). The electrospinning method was used to prepare BT fibers. Phase structure was carried out by the x-ray diffraction (XRD) technique. By using the Rietveld refinement method, a tetragonal structure of BT fiber could be confirmed. The scanning electron microscopy results showed a non-smooth surface of BT fibers, indicating the polymeric and organic precursors have been removed. The fabricated FPENG with 50% ratio of BT fibers was capable to generate an open-circuit voltage of ≈ 12 V and a short-circuit current of ≈ 1 μA. The effect of dispersed phases inside FPENG becomes the role to improve the output performance. This FPENG device can operate up to 5k times before degeneration. By continuously pressing up to 40k times, the output voltage tended to decrease reaching to a null value. The mechanical fatigue effect has been found that it related to the damage produced at the interface between IDEs and PDMS during pressing. The present results can be guided to further design the material and the device structure to obtain high-performance and stability of the FPENG devices.

High Volume Production of PZT Fiber Arrays for Direct Functional Integration into Metal Structures

A new concept for electromechanical coupling of piezoceramic to metal structures is enabled with the technology of joining by forming. This approach allows for the manufacturing of so‐called piezo‐metal modules. To make the manufacturing process ready for series production, it is necessary to fabricate lead zirconate titanate (PZT) fiber arrays with high geometric accuracy. In addition, the aim is to design the PZT fiber arrays so that they are usable with either piezoelectric transversal, longitudinal, or shear mode to enable different application options. In particular, the realization of the shear mode offers new application potentials in comparison to commercially available products. This paper presents both, a high volume production method, and the specific order for the production steps of PZT fiber arrays to achieve the different piezoelectric modes. In particular, the usable piezoelectric effects are determined by the order of the coatings of electrode and insulating layers as well as the direction of the polarization. Experimentally produced samples are tested in functional tests before and after the joining by forming process. The results verify the proof of the production method of PZT fiber arrays with a high accuracy. Furthermore, structurally integrated PZT fiber arrays demonstrate the functional use of the three piezoelectric modes in the plane of an aluminum sheet. Fabricated piezo‐metal modules with transversal mode and shear mode are successfully verified in sensory function. The longitudinal mode is tested in actuator function. During the tests, failures for the insulation layer are identified. These can be eliminated with a modified manufacturing process, which is proposed.

Electrospun sodium titanate fibres for fast and selective water purification

ABSTRACTFrom the environmental and end-users’ viewpoints, electrospun ion exchange fibres provide highly efficient and sustainable material for separation of for example trace pollutants, such as radionuclides and heavy metals. This work aimed to reduce the amount of ion exchange material needed per unit volume of raw material subjected to an ion exchange process. We present a very simple process to electrospinning of sodium titanate fibres, but also test results of ion exchange kinetics measurements. Sodium titanate fibres are very promising material and it is possible that by exploiting electrospun inorganic sub-micron fibres the ion exchanger mass required for a given capacity can be decreased significantly.

Influence of Electrode Layers on the Fracture Strength of PZT Ceramics

A newly developed process chain enables the production of active structural components. Thereby lead zirconate titanate (PZT) fibres are integrated in metal sheets by joining by forming. For the further development of the process chain to a high volume production the fracture strength of PZT should be increased. This paper pursues the approach to increase the strength by selected electrode layers. For this purpose, various electrode layers are tested on PZT plates in strength tests with the ball on three balls test (B3B-test). The evaluation of the recorded values is carried out according to statistically methods. The results show that the strength of PZT can be increased by electrode layers up to 30%. In addition, it was established that a high tensile strength and a high Young’s modulus of the electrode layers do not have a positive effect on the strength of PZT.

Preparation of Hollow Hithium Titanate Fiber Tube By Electrospinning

With the progress of science and technology, notebook computers, microcomputers, digital cameras, mobile phones and other new electronic equipment come out one after the other. The development of new products to the storage of energy have a greater demand, the traditional graphite anode material has been unable to meet its performance needs. The spinel lithium titanate is a lithium ion battery anode material with good cycling capability, wide operating temperature range and good safety performance. However, due to the poor electrical conductivity and low lithium-ion diffusion coefficient, the rate performance is very limited. Therefore, increasing rate performance of lithium titanate anode material becomes the only way of application of lithium titanate . In this paper, lithium titanate is prepared by coaxial electrospinning. With the High molecular weight polymer polyvinylpyrrolidone (PVP) providing high viscosity，a solution spinning solution of PVP and absolute ethanol is used as the inner layer template solution. The Part of solution with a lithium source and a titanium source set as an outer layer precursor solution. After the titanate precursor fiber filaments are calcined, with core and outer PVP are removed the hollow lithium titanate filament is finally obtained. Figure a is cycle-capacity curve of the hollow lithium titanate anode material after prepared into a button cell. The first 0.2C rate of the specific capacity is 174.9mAhg-1 with theoretical specific capacity flat, and at the 30C specific capacity can be to 105 mAhg-1, which can achieve that Li-ion battery immediately charge. Figure b shows that, at low charge and discharge rate, lithium titanate discharge platform is relatively stable, while platform stability is poor at the high charge and discharge rate. Figure 1. (a) Discharge capacity curves of lithium titanate at different charge and discharge rate; (b) the first discharge profiles of lithium titanate at the different charge and discharge rate. Reference [1] Cho, Y., Lee, S., Lee, Y., Hong, T., & Cho, J. (2011). Spinel-layered core-shell cathode materials for li-ion batteries. Advanced Energy Materials,1(5), 821–828. [2] A. K. Moghe, & Professor B. S. Gupta. (2008). Co‐axial electrospinning for nanofiber structures: preparation and applications. Polymer Reviews,48(2), 353-377. [3] Tong, H., Tao, X., Wu, D., Zhang, X., Li, D., & Zhang, L. (2014). Preparation and characterization of doped tio 2, nanofibers by coaxial electrospining combined with sol–gel process. Journal of Alloys & Compounds, 586(10), 274-278. Acknowledgment Thanks for being funded by the Technology Research Program of the State Grid about Preparing Submicron Lithium Titanate-based Materials for Energy Storage Batteries (DG71-15-042) . Figure 1

Transparent lead lanthanum zirconate titanate (PLZT) ceramic fibers for high-frequency ultrasonic transducer applications

This paper presents fabrication of transparent lanthanum zirconate titanate (PLZT) fibers using extrusion technique. The diameter of the sintered PLZT fiber is about 400-μm, and the fibers exhibit very good transparency. Measured dielectric constant, remnant polarization and coercive field of PLZT fiber were found to be 2340, 22.5-μC/cm2, and 9.8-kV/cm, respectively. The transparent piezoelectric materials may exhibit great potential for Photoacoustic (PA) imaging and hybrid intravascular imaging combining OCT and ultrasound imaging by using the transparent fiber as the path of light propagation and ultrasonic transducer material. In our study, these transparent PLZT fibers were designed to fabricate two types of high-frequency ultrasonic transducers: small aperture single PLZT fiber/epoxy composite and large aperture 1–3 PLZT fiber/epoxy composite ultrasonic transducers. Besides, a 20-μm tungsten wire phantom and the cornea of the porcine eye were also imaged with the 1–3 PLZT fiber/epoxy composite ultrasonic transducer to demonstrate its imaging capability.

Square cross-section piezoelectric fiber composites: structure and ferroelectric properties

Square cross-section lead zirconate titanate (PZT5) fibers were fabricated by viscous polymer processing. Fibers were perpendicularly arranged in glass tubes and infiltrated with bisphenol-A epoxy resin E51 to form 1–3 composite structures. Phase, micromorphology, mechanical properties and electric properties were identified for fibers and composites. As a result, PZT5 ceramic fibers sintering at high temperature above 1280 °C have pure trigonal perovskite phase and side length of ~300 μm. A brittle broken mechanism was put forward by the linear stress–strain curves of PZT5 fibers. 1–3 composites with 30 % fiber volume fraction demonstrated closed and saturated P–E loops, high remnant polarization P r of 15.94 μC/cm2 and low coercive field E c of 0.91 kV/mm. Moreover, the composites performed high piezoelectric strain constant d 33, piezoelectric voltage constant g 33 and high anisotropy parameters k t/k p. The acoustic impedance Z was about one-third of PZT5 ceramics. The above performances of PZT5 composites showed an excellent application prospect in the fields of ultrasonic medical imaging systems and nondestructive testing.