Thin Ti Foil Research Articles

Carbon nanotubes as efficient anode current collectors for stationary aqueous Zn–Br2 batteries

Static Zn–Br2 batteries are considered an attractive option for cost-effective and high-capacity systems for large energy storage. Yet, the corrosive nature of the Zn–Br2 electrolytes entails a careful selection of all cells' ingredients to avoid rapid degradation of the batteries upon cycling. Thanks to their high chemical resistance and excellent conductivity, carbonaceous electrodes are typically utilized as current collectors for the cathode side, while thin Zn or Ti foils are most widely used as the anodes' current collectors. However, these metals tend to corrode fast, thus undermining the desirable performance of the cells as durable and stable rechargeable batteries. We demonstrate the effective utilization of carbon nanotubes (CNT) films as highly stable anode current collector for Zn–Br2 batteries. Dispersion of the CNT beforehand in slurries containing anionic, cationic, or neutral surfactants yielded distinct chemical and physical characteristics of these carbonaceous electrodes. This, in turn, led to significant differences in the morphology of the deposited Zn, consequently affecting the electrochemical performance of the Zn anodes. These findings provide insight into the interactions between Zn cations and the surface of CNTs, offering opportunities for further surface modifications of CNTs as effective anodes’ substrates for Zn–Br2 batteries.

MoS2 thin film decorated TiO2 nanotube arrays on flexible Ti foil for solar water splitting application

MoS2/TiO2 nanostructure provides a lot of advantages in photoelectrochemical (PEC) applications due to the absorption of the wide spectrum solar radiation, more catalytically active sites, proper band alignment, and better separation of photogenerated charge carriers. Here we report PEC water splitting studies of MoS2 thin film grown by chemical vapor deposition on TiO2 nanotubes fabricated on flexible thin Ti foil. Raman and x-ray diffraction analysis confirmed the polycrystalline growth of a few layers MoS2 on TiO2/Ti through their characteristic peaks. Field emission scanning electron microscopy revealed the nanotube surface morphology of TiO2 having a diameter in the range of 200–300 nm. The chemical and electronic composition of MoS2 and TiO2 were investigated by x-ray photoelectron spectroscopy. PEC measurements performed in 0.5 M Na2SO4 aqueous electrolyte solution under 100 mW cm−2 (AM 1.5G) simulated sunlight revealed 2-fold improved photocurrent density for MoS2/TiO2 heterostructure (∼135.7 μA cm−2) compared to that of bare TiO2 (∼70 μA cm−2). This is attributed to extended light absorption and more catalytically active surface area resulting from MoS2 functionalization of the TiO2 nanotubes, which results in better PEC activity. This study provides a new insight to explore the performance of thin metal foil-based photoelectrode in PEC applications that can be beneficial to develop roll-to-roll device fabrication to advance futuristic flexible electronics.

Continuous Mo fiber reinforced Ti/Al3Ti metal-intermetallic laminated composites

In this work, continuous Mo fiber as a reinforcement was introduced into Ti/Al3Ti metal-intermetallic-laminated (MIL) composite via vacuum hot pressing (VHP). In order to avoid excessive consumption of Mo fibers reacting with Al, and also obtain an appropriate amount of Al3Ti, a Ti foil with the thickness of 0.1 mm as an expendable was inserted between the Al foil and Mo fibers. The microstructure characterization of the MIL composite was performed via X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the tensile mechanical properties were measured by employing an Instron-5500R load frame. Results indicated that after VHP, the inserted thin Ti foils were completely depleted and converted into the dominant phase Al3Ti, which existed in the intermetallic layer. Four Al–Mo intermetallic, Al8Mo3, Al4Mo, Al5Mo and Al12Mo were successively formed around Mo fiber. The sequence of these Al–Mo intermetallic can be well explained by the thermodynamics calculation combined with the kinetic factor. Tensile tests show that when the arrangement of the fibers is parallel to the tensile direction, the introduction of Mo fibers significantly improves the tensile strength and strain to failure of the composite fibers, which is obviously related to the excellent mechanical properties of the Mo fibers themselves and their good bonding with the matrix.

High-performance energy storage and breakdown strength of low-temperature laser-deposited relaxor PLZT thin films on flexible Ti-foils

The microstructure, ferroelectric, electric-field breakdown strength, and energy-storage properties of relaxor Pb0.9La0.1(Zr0.52Ti0.48)O3 (PLZT) thin films grown on flexible Ti foils using pulsed laser deposition were systematically investigated. Low temperature deposited PLZT thin films showed very slim polarization hysteresis loops with a high difference between maximum and remanent polarizations and low remanent polarization through modulating the film structure with a small columnar-grain size. An ultrahigh recoverable energy density (Ureco) of 40.9 J/cm3, excellent energy efficiency (η) of 80.2% and large breakdown strength (EBD) of 3000 kV/cm were achieved in a PLZT film deposited at the low temperature of 480 °C. More importantly, this film shows excellent charge-discharge cycling endurance with a small variation of both Ureco and η values (less than 3%) after 1010 cycles and good thermal stability under a wide operating temperature range from room temperature to 200 °C. These results indicate that the relaxor PLZT films deposited on thin Ti foils, even at low temperature, are a promising strategy to enhance energy-storage performance for pulse-power energy-storage systems with broad temperature range applications, especially in applications where the device weight is critical (lightweight) due to the thin and low density of Ti foils.

Tailoring the interfacial microstructure and mechanical strength of SiC ceramic joints using joining temperature and interlayer thickness

Silicon carbide ceramic joints solid state diffusion bonded by spark plasma sintering with Ti/Ta-5W/Ti multi-interlayer in the temperature range from 1250 °C to 1500 °C were investigated in detail in terms of interfacial microstructure, elemental diffusion, phase constituents, shear strength, and fracture morphology. Layered reaction layers consisting of carbides (TiC, Ti3SiC2, (Ta,Ti,W)C), silicide ((Ta,Ti,W)5Si3) and Ta-rich solid solution (Ta,Ti,W) formed at the SiC/Ti/Ta-5W interfaces. It was found that joining temperature could be decreased from 1600 °C to 1300 °C by inserting the Ti foil between SiC and Ta-5W. Nevertheless, an attempt to further decrease the joining temperature to 1250 °C failed even using a thin Ti foil. The initial thickness interlayer and the number of interlayer had an influence on the interfacial diffusion bonding at SiC/Ti interface. Higher joining temperature was needed to achieve a tough interface joining for a thick interlayer compared with a thin interlayer. The increase of interlayer number also required higher joining temperature. The shear strength reached 123.5 ± 25.3 MPa for the joint diffusion bonded at 1300 °C.

TiO2 nanotubes grown on Ti substrates with different microstructure

Four Ti substrates with various microstructures were investigated for the anodic growth of TiO2 nanotube layers: nanocrystalline and single-crystalline ingots as well as microcrystalline thick Ti sheets and microcrystalline thin Ti foils. All substrates were anodized in a conventional ethylene glycol based electrolyte under identical conditions. The resulting TiO2 nanotube layers were compared in dimensions and the consumption of Ti required for their growth. Unexpectedly, the results showed that on all substrates nanotube layers with a similar thickness and nanotube diameter, as well as a similar degree of ordering and after annealing the same crystallographic orientation of anatase were received, regardless the microstructures. However, the nanotube layers grown on a Ti sheet revealed a slightly higher thickness compared to the other substrates which were assigned to slower field-assisted dissolution rates due to different impurities found in this substrate compared to other ones.

Comprehensive studies on microstructural, electronic, thermo-optical, mechanical and tribological behavious of vacuum heat treated ultra thin CP Ti foils

Present study reports the effect of vacuum (10−5 mbar) heat treatment (300 °C–900 °C) on the microstructural, electronic, thermo-optical, mechanical and tribological properties of commercially pure (CP) titanium (Ti) ultra thin (75 µm) foil. Phase analysis and surface morphology of the as-received and vacuum heat treated Ti foil samples were investigated by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and profilometry techniques. X-ray photoelectron spectroscopy (XPS) was employed to understand the electronic structure of the Ti foil surfaces. The solar absorptance (αs), solar reflectance (ρs) and IR emittance (εir) of the as-received and vacuum heat treated Ti foil samples were evaluated. For vacuum heat treatment temperatures above 700 °C these properties were significantly altered. Nanoindentation study was carried out to evaluate hardness and elastic modulus while single pass scratch tests were performed to understand the tribological behaviour of the as-received and vacuum heat treated Ti foil samples. Further, yield strength and elongation of the as-received and vacuum heat treated Ti foil samples were measured from the tensile tests. Based on the experimental results it is suggested that the nanoindentation response of the as-received and vacuum heat treated Ti foil samples can be significantly affected by presence or absence of residual stress and pile-up around the nanoindents. Moreover, the results implied that possibly the formation of hard and brittle TiC phase during vacuum heat treatment temperature at and above 700 °C had influenced the thermo-optical, mechanical and tribological properties of the thin Ti foils.

Highly periodic laser-induced nanostructures on thin Ti and Cu foils for potential application in laser ion acceleration

The feasibility of femtosecond laser-induced periodic nanostructures on thin Ti and Cu foils (thickness down to 1 μm) is demonstrated. At pulse durations of 120 fs and a wavelength of 400 nm, periods of 61 nm to 320 nm were obtained. Particle-in-cell simulations of laser ion acceleration processes with such nanostructured targets indicate their potential for high energy particle physics applications. In particular, a measurable enhancement of the proton cut-off energy and a significant enhancement of the number of accelerated particles compared to non- or weakly structured targets of same thickness and material are expected.

Nonlinear mechanical properties estimated from images of a mechanical test

The problem of identifying the (non-linear) mechanical properties of a solid from images taken in a mechanical testing machine is considered. The two classical steps of i) measuring the displacement field with digital image (and volume) correlation and ii) identifying the mechanical properties from the displacement field are combined into a single "integrated" procedure to reduce the artificial bias introduced from the projection of the kinematic data onto an arbitrary displacement basis. It allows for the identification of nonlinear constitutive law parameters with arbitrarily complex kinematics. The example of the plastic behavior of thin Ti-foils is considered.

Dry plasma reduction to synthesize supported platinum nanoparticles for flexible dye-sensitized solar cells

A dye-sensitized solar cell (DSC) can be a promising device as a ubiquitous power source, if it is flexible. Since the annealing step of TiO2 nanoparticles (NPs) is a major obstacle to using a thermoplastic film as a transparent photoanode (PA), a transparent counter electrode (CE) using a thermoplastic film as a photo illumination window can be a reasonable alternative for developing a flexible DSC together with a non-transparent PA using a flexible metal foil coated with TiO2 NPs. To achieve this purpose together with improving photo conversion efficiency, it is necessary to deposit highly active supported platinum (Pt) NPs with homogeneous size dispersity on the surface of a transparent conducting oxide (TCO). Various methods developed so far, however, have critical process restrictions such as high temperature, low pressure, liquid environment, and chemical toxicity, which render them difficult to develop into an economic continuous process. Here we report an excellent method of directly depositing Pt-NPs on the surface of a TCO using dry plasma reduction (DPR) under atmospheric pressure without using any toxic chemicals while keeping the temperature below 70 °C. After determining an optimum concentration of Pt precursor solution to maximize the photovoltaic performance of DSCs, we successfully demonstrate a new flexible DSC which is composed of a non-transparent PA using thin Ti foil coated with TiO2 NPs and a transparent CE, as a photo illumination window, using Pt-NPs supported on a PET/ITO film.

Hydrothermal growth of free standing TiO 2 nanowire membranes for photocatalytic degradation of pharmaceuticals

Highly entangled TiO 2 nanowires were directly synthesized by hydrothermal growth on Ti substrates at 180 °C utilizing various organic solvents to oxidize Ti. The growth mechanism, microstructure and phase transition of TiO 2 nanowire membranes were investigated in detail. TiO 2 nanowires, with diameters of 10–20 nm and lengths up to 100 μm, show a phase transition from Type-B to anatase by annealing at 700 °C. Robust, free standing TiO 2 nanowire membranes with millimeter level thickness can be cleaved from Ti substrates or directly prepared from thin Ti foils. These porous TiO 2 membranes, while effective for mechanical microfiltration, can also photocatalytically degrade pharmaceuticals such as trimethoprim under UV irradiation.

Directional Bremsstrahlung from a Ti Laser-Produced X-Ray Source at Relativistic Intensities in the 3–12 keV Range

Front and rear side x-ray emission from thin titanium foils irradiated by ultraintense laser pulses at intensities up to ≈5 × 10(19) W/cm2 was measured using a high-resolution imaging system. Significant differences in intensity, dimension, and spectrum between front and rear side emission intensity in the 3-12 keV photon energy range was found even for 5 μm thin Ti foils. Simulations and analysis of space-resolved spectra explain this behavior in terms of directional bremsstrahlung emission from fast electrons generated during the interaction process.

Size-Selective Separation of Macromolecules by Nanochannel Titania Membrane with Self-Cleaning (Declogging) Ability

We report on a simple and self-organizing process for the fabrication of TiO(2) nanochannel membranes with a channel width of 8-10 nm that can be used for size selective separation of macromolecules (proteins). The membrane, consisting of self-aligned oxide channels, is formed by complete anodization of a thin Ti foil under specific electrochemical conditions in a glycerol-phosphate electrolyte. Due to self-cleaning properties of TiO(2), clogged membranes (for example due to extended use) can easily be fully reopened and thus are reusable. As the TiO(2) after anodic formation directly contains anatase crystallites (the most photoactive TiO(2) crystal form) no thermal treatment of the membrane is required (avoiding the danger of thermally induced cracking).

Temperature andKα-yield radial distributions in laser-produced solid-density plasmas imaged with ultrahigh-resolution x-ray spectroscopy

We study warm dense matter formed by subpicosecond laser irradiation at several 10(19) W/cm(2) of thin Ti foils using x-ray spectroscopy with high spectral (E/DeltaE approximately 15,000) and one-dimensional spatial (Deltax=13.5 microm) resolutions. Ti Kalpha doublets modeled by line-shape calculations are compared with Abel-inverted single-pulse experimental spectra and provide radial distributions of the bulk-electron temperature and the absolute-photon number Kalpha yield in the target interiors. A core with approximately 40 eV extends homogeneously up to ten times the laser-focus size. The spatial distributions of the bulk-electron temperature and Kalpha yield are strongly correlated.

Titanium plasma source for capillary discharge extreme ultraviolet lasers

A technique to generate jets of pure Titanium plasma is presented. A Ti wire is exploded in an Alumina capillary sealed with 1 atm. of air inside. The generated plasma emerges from the capillary (to a high-vacuum environment) by ripping a thin Ti foil that seals one of the capillary ends. The generated plasma jets have a velocity of up to 4.5±0.5mm∕μs, an electron temperature of 1.5±0.5eV and an ion density of 2.7±1×1017∕cc. The plasma source was designed for a capillary discharge extreme ultraviolet laser experiment, but might also be useful to other application such as a target for Z-pinch experiments.

Characterization of a picosecond laser generated 4.5keV TiK-alpha source for pulsed radiography

K α radiation generated by interaction of an ultrashort (1ps) laser with thin (25μm) Ti foils at high intensity (2×1016W∕cm2) is analyzed using data from a spherical Bragg crystal imager and a single hit charge-coupled device spectrometer together with Monte Carlo simulations of Kα brightness. Laser to Kα and electron conversion efficiencies have been determined. We have also measured an effective crystal reflectivity of 3.75±2%. Comparison of imager data with data from the relatively broadband single hit spectrometer has revealed a reduction in crystal collection efficiency for high Kα yield. This is attributed to a shift in the K-shell spectrum due to Ti ionization.

Antireflection foils with multi-layer converter for ultracold neutron detectors

For experiments at the ultracold neutron (UCN) source of the new high-luminosity neutron source, Forschungsreaktor München II (FRM II), highly efficient detectors are needed. The desired type of detectors utilizes 6Li as the neutron converter based on the huge cross-section reaction 6Li(n, α)t and detection of the 2.06 MeV α-particles or the 2.73 MeV t-particles. The high reflectance of UCN from 6Li with its positive optical potential must be compensated by a material with negative optical potential. Instead of the expensive 62Ni material, natural Ti can be chosen. It was demonstrated that neither 6Li metal nor Ti metal can be deposited in a high-vacuum evaporation apparatus without creating a positive optical potential and thus increasing the reflectivity for the UCN due to oxygen impurities coming from the H 2O partial pressure in the high-vacuum system. To overcome these problems, a new UHV evaporation apparatus was developed and built which is capable of reaching a vacuum in the 10 −10 Pa range. Such a good vacuum can be obtained only when annealing the vacuum system up to 470 K. At such a high annealing temperature the silicon detectors for the α- and t particles might suffer degradation of their energy resolution. Therefore, the multi-layer system of 6Li and natTi is not deposited directly on the silicon detector but a thin rolled Ti foil is applied as backing. A test deposition of 200 double layers of 6LiF/ 62Ni on a thin Ti foil is described and a report is given about the setup of the new UHV evaporation apparatus.

Recording a line profile across ion‐implanted conductor paths in Si wafers by a synchrotron beam microprobe

AbstractSynchrotron radiation was applied to recording a line profile across buried conductive paths in a silicon 〈100〉 wafer. For that purpose, Co ions were first implanted in a depth of 60 nm below the silicon surface with a dose of 1017 cm−2 and an energy of 100 keV. By means of a photoresist mask, small strips of ca 150 and 40 µm width were produced. The analytical characterization was performed at DESY/HASYLAB by concentrating the synchrotron beam with a cylindrical and a tapered capillary with an effective diameter of 10 and 4 µm, respectively. The implanted wafer was shifted in steps of 1 µm on a straight line along a capillary in order to record a line profile of the implanted element cobalt across the buried strips. An internal standard was used in order to compensate for the large long‐term drift and the strong fluctuations of the synchrotron beam. A 0.1 µm thin Ti foil turned out to be a very simple standard easily placed in front of the implanted wafer. This aid facilitates an examination of buried layers with a flank down to only micrometer steepness and with a uniform plateau down to only 1% deviations. Copyright © 2002 John Wiley & Sons, Ltd.

Diffusion bonding of aluminium oxide to stainless steel using stress relief interlayers

Aluminium oxide was diffusion bonded to AISI 304 steel using Ti, Cu or Mo as interlayer materials. It was observed that Ti joins easily to both ceramic and steel parts, giving an average shear strength equal to 20 MPa. However, within the experimental conditions applied, the adhesion between Al 2O 3 and Cu or Mo was unsuccessful. A finite element modelling (FEM) was employed to evaluate the residual stresses in the joints and showed that the use of Mo and Cu reduced the stress level, when comparing to Ti. Results from the FEM suggests that similar behaviour is expected when an interlayer comprising a thin Ti foil in contact with the alumina and a thick Cu or Mo foil is used. Diffusion bonding experiments using such combinations substantiated the FEM results and the average strength of the joints reached 27 MPa with Ti/Mo and 65 MPa with Ti/Cu. Ti 3Al formation was found to be responsible for the Al 2O 3/Ti adhesion whilst β-Ti phase stabilisation was detected at the Ti/steel interface and attributed to the intense diffusion of Fe into the Ti.

Cross-sections for 36Cl from Ti at E p=35–150 MeV: Applications to in-situ exposure dating

We have measured the low-energy yield of 36Cl from Ti for proton energies from 35 to 150 MeV. Thin Ti foil irradiations were performed at the Harvard University Cyclotron Laboratory and 36Cl concentrations were determined using the ANTARES AMS facility at ANSTO. Cross-sections ranged smoothly with energy from 0.32±0.05 mb at 35 MeV to 5.3±0.4 mb at 150 MeV. Results for E<110 MeV are new, while the upper region from 110 to 150 MeV agrees well with overlapping data from other studies. The in-situ production rate for 36Cl from Ti at the earth’s surface and high latitude based on this excitation function and calculations of Masarik and Reedy (normalised to the mean measured yield of 36Cl from Ca) is estimated at ∼(13±3) atoms 36Cl (g Ti yr) −1. We thus conclude that in Ti-rich, Ca-poor rocks or in typical basalts, 36Cl yield from Ti can amount to ∼5–10% of total. This is similar to the contribution from slow muon capture on 40Ca and in some cases, from thermal neutron capture on native Cl.