Ti Foil Research Articles

Synthesis and optical properties investigation of TiO2 ‎nanotubes for use in polymer gel-state dye sensitized solar cells

In this paper highly ordered TiO2 nanotube (TNT) arrays were synthesized using potentiostatic anodization of Ti foil for 12 h at voltage of 60 V and used in polymer gel-state dye senisitized solar cells (DSSCs) . To investigate the morphology and optical properties of the TNTs, scanning electron microscopy (SEM), Raman spectroscopy and X-ray diffraction techniques (XRD) have been used. The average diameter and length of the TNTs were 100 nm and 30 µm, respectively. XRD and Raman measurements indicated the pure anatase phase of TNTs. A polymer poly(methyl metacrylate- co-methacrylic acid) (PMMA-MA) was mixed with a 3-methoxypropionitrile (MPN) based liquid electrolyte to prepare a gel-state polymer electrolyte. The prepared electrolytes containing varied concentrations of PMMA-MA were characterized by electrochemical impedance spectroscopy (EIS). Power conversion efficiency of NT based DSSCs using a polymer gel electrolyte containing PMMA-MA was comparable with that of the corresponding liquid counterpart.

TiO2 Nanowire Arrays in situ Grown on Ti Foil Exhibiting Superior Uranyl-Adsorption Properties

TiO2 nanowire arrays in situ grown on Ti foil (TiO2/Ti) were prepared to remove uranium (VI) from aqueous solution. As the Ti foil serves as a carrier for TiO2, the TiO2/Ti adsorbent can be effortlessly retrieved from aqueous solutions by tweezers after adsorption. The presence of TiO2 nanowire arrays on Ti foil was verified by X-ray diffraction and scanning electron microscopy. Parameters in the adsorption process were fully evaluated, including solution pH, contact time, temperature, and uranium (VI) concentration. The adsorption was most efficient in the pH range of 5.0 to 9.0. The maximum uranium (VI) adsorption capacity of TiO2/Ti, based on the Langmuir model, was 354.5 mg g–1 at pH 5.0 and T = 323 K. Thermodynamic parameters showed that the adsorption of uranium (VI) on TiO2/Ti is endothermic and spontaneous. The adsorption capacity of TiO2/Ti remained essentially unchanged after three adsorption–desorption cycles in uranium (VI) solutions. Our results support the application of this adsorbent to removal of uranium (VI) from diversified aqueous samples.

The Morphological Development of Ordered Nanotube Structure Due to the Anodization of Ti Foil with Axial and Radial Current Flow

Background: One-dimensional titania nanotubes (TNT) have attracted increasing scientific and technological attention due to their physical properties and their potential applications. Dimensionality and well-aligned ordered structure have a crucial role in determining the properties and performance of titania nanotubes. Therefore, an understanding of the transformation and growth mechanisms to explain the origin of this nanomaterial symmetry is of great importance. Objectives: The relationship between the direction of current flow and the morphology of the anodized foil was investigated to understand the influence of a compact oxide layer formation on the growth of nanotubes. Methods: To achieve the purpose, single (SA) and double-sided anodization (DA) were performed to control the direction of the current flow in this experiment by immersing one side and both sides, respectively in the electrolyte containing 0.6 wt% of NH4F, 1.0 wt% of H2O2, and 98.4 wt% of ethylene glycol (EG) at 60V. Results: It was found that the channeling of current flow into axial and radial directions influenced the effectiveness of oxygen species in the formation of an initial oxide layer. The field-assisted dissolution of the compact oxide layer resulted in a low-symmetry nanotube arrangement, whereas the growth at the interface, which is governed by the plastic flow mechanism, resulted in high-symmetry nanotube arrangement in a hexagonal form. These findings offer an integrated perspective when determining whether the plastic flow mechanism or field-assisted dissolution occurs during anodization. Octahedral titania crystals were also found on the surface of the anodized film, indicating the possibility of forming facet structures via anodization. Conclusion: This research successfully showed the influence of current flow via SA & DA on the growth of TiO2 nanotubes. An axial flow of current in Ti foil during SA resulted in disordered nanotubes, while the radial flow of current during DA stemmed the growth of nanotubes from the Ti-TiO2 interface to form well oriented hexagonal nanotube structures.

Liquid phase deposition/anodizing of TiO2 nanotube working electrode for dye-sensitized solar cells

With a high carrier transfer rate, anodizing TiO2 nanotubes (TNTs) are often used as the working electrode in dye-sensitized solar cells (DSSCs). However, the TNT length is restricted by the thickness of the Ti foil, which in turn limits the dye adsorption efficiency of the working electrode. To combat this problem, this study used liquid-phase deposition (LPD) to fabricate a TiO2 film on anodizing TNT. LPD allows for more rapid and even deposition of TiO2 films on the anodizing TNT structure than does vacuum deposition. Analysis revealed that LPD-TiO2 films fabricated at 3.33 nm/s increased the length of the TNT from 17.76 to 24.80 μm, and the dye adsorption capacity rose from 9.8 × 10−7 to 1.07 × 10−6 mol/m3. Testing confirmed that the photoelectric conversion efficiency of the DSSC device of the LPD/anodizing TNT increased from 2.43% to 2.85%, that the interface impedance of the DSSC device (R2) decreased from 132 to 41.5 Ω, and that the electron lifetime (τe) increased. In sum, the LPD-TiO2 film increased the thickness, dye adsorption efficiency and reduced the oxygen vacancies in the anodizing TNT; in other words, the coating effectively enhanced the photoelectric conversion properties of the DSSC device of the working electrode.

Effect of the Length of TiO2 Nanotube Arrays on Responsivity of Photoelectrochemical-Based Ultraviolet Photodetectors

In this study, one-dimensional titanium dioxide (TiO[Formula: see text] nanotube arrays (NTAs) with different tube lengths are synthesized via anodic oxidation of Ti foils and their ultraviolet (UV) light detection properties are investigated to determine their optimum growth conditions. A TiO2 nanotube ultraviolet photodetector based on photoelectrochemical cell is fabricated using the optimum TiO2 nanotubes and its characteristics in the ultraviolet region are determined. The photodetector is examined under a UV illumination intensity of 10[Formula: see text]mW/cm2and at a wavelength of 368[Formula: see text]nm. Its responsivity is measured to be about 96[Formula: see text][Formula: see text]A/cm2 and its response time is less than 0.2[Formula: see text]s under an applied bias of 0.5[Formula: see text]V.

Effect of laser-Ti foil coupling on microstructure and mechanical property of steel/aluminum fusion welding joints

The experiment of steel/aluminum laser welding was carried out, numerical simulation of temperature and flow fields inside molten pool was analyzed, and the effect of laser-Ti foil coupling on microstructure and mechanical property of steel/aluminum fusion welding joints was also investigated. With the increase of laser power, the increased penetration width and depth are obtained. The shear force of joint climbs up at first, then declines, and reaches the maximum value when laser power is 1.4 kW, which is improved by 43% compared with that of 1.2 kW. Meanwhile, fracture mode changes from brittle fracture to a mixture of brittle and ductile fractures. In the case of the increased laser power, the improved joint properties are dominated by the metallurgical regulation of Ti foil, which benefits from the accelerated flow of molten pool leading to the Ti element aggregation at the interface and the formation of some new phases. However, when laser power is relatively low, the flow velocity of liquid inside molten pool goes down, and the metallurgical regulation effect of Ti foil is inconspicuous. The property of steel/aluminum joint can be improved by enlarging the steel/aluminum combination area and facilitating Ti foil to generate new phases, but excessive heat input will cause burning loss and induce thermal crack defects, which deteriorates the joint properties.

Microstructure and mechanical properties of in situ TiC/Ti composites with a laminated structure synthesized by spark plasma sintering

A series of novel in situ TiC/Ti composites with laminated microstructure have been fabricated via electrophoretic deposition followed by spark plasma sintering (SPS), in which the electrophoretic deposition has been used to deposit graphene oxides (GOs) on commercially pure Ti foils and the SPS has been used to induce in situ reaction between Ti and GOs to form TiC and simultaneously achieve densification. With increasing deposition duration, the volume fraction of TiC reinforcement increases and the grain size of Ti matrix decreases in the as-sintered composites, resulting in continuous strength increment. Attributed to the introduction of TiC reinforcement and laminated structure, a strength increment of 93.9% can be reached with a considerable elongation of 6.1%. Moreover, different strengthening mechanisms are discussed and quantitatively evaluated based on microscopy analysis. • Laminated TiC/Ti composites were synthesized by spark plasma sintering. • The composites exhibited better strength-ductility combination. • The strengthening mechanisms are discussed and quantitatively evaluated.

Effects of SiC Fibers and Laminated Structure on Mechanical Properties of Ti-Al Laminated Composites.

Ti/Ti–Al and SiCf-reinforced Ti/Ti–Al laminated composites were fabricated through vacuum hot-pressure using pure Ti foils, pure Al foils and SiC fibers as raw materials. The effects of SiC fiber and a laminated structure on the properties of Ti–Al laminated composites were studied. A novel method of fiber weaving was implemented to arrange the SiC fibers, which can guarantee the equal spacing of the fibers without introducing other elements. Results showed that with a higher exerted pressure, a more compact structure with fewer Kirkendall holes can be obtained in SiCf-reinforced Ti/Ti–Al laminated composites. The tensile strength along the longitudinal direction of fibers was about 400 ± 10 MPa, which was 60% higher compared with the fabricated Ti/Ti–Al laminated composites with the same volume fraction (60%) of the Ti layer. An in situ tensile test was adopted to observe the deformation behavior and fracture mechanisms of the SiCf-reinforced Ti/Ti–Al laminated composites. Results showed that microcracks first occurred in the Ti–Al intermetallic layer.

Facile synthesis of MoS2 nanosheets-deposited TiO2 nanotubes array electrode for enhanced electrocatalytic hydrogen evolution reaction

MoS2 nanosheets were fabricated by ultrasonication of bulk MoS2 and TiO2 nanotubes array (TNA) was formed on Ti foil via anodization method. Using facile and binder-free electrophoretic technique, MoS2 nanosheets were deposited on the TNA as high surface area and well-ordered support to fabricate the MS/TNA electrode. In electrocatalytic hydrogen evolution reaction (HER), the MS/TNA indicated a low onset potential and overpotential of 85 mV at current density of −10 mA/cm2 with Tafel slope of 39 mV/dec. Furthermore, after 1000 cycles, the MS/TNA displays high stability in HER. Our results demonstrated that the MoS2 nanosheets on the TNA provide more active sites while the ordered tubular TNA support creates straight pathways for electron transport toward MoS2 nanosheets with improved interaction of the electrolyte and electrode in HER. This work introduces the MS/TNA as an efficient and cost-effective electrode for electrocatalytic production of hydrogen.

Direct Self-Assembly of Hierarchically Grown Rhodium Thin Films for Electrocatalytic Hydrogen Evolution Reaction

Thin films of metallic rhodium (Rh) are developed on two different supports, nickel foam (NF) and titanium foil (Ti), and evaluated for electrochemical hydrogen evolution reaction (HER). The electrodes are prepared by aerosol-assisted chemical vapor deposition technique using a Rh diethyldithiocarabamte precursor for three distinct time periods of 40, 80, and 120 min at 500 °C. The film consists of phase pure metallic Rh with hierarchical flower-like morphology. The structural features of such nanostructures can be modulated by adjusting the growth time. The HER catalytic performance data for the optimized films (i.e., with the deposition time of 80 min) suggest that the Rh deposited on Ti foil (Rh/Ti) catalyze the reaction substantially faster than Rh deposited on Ni foam (Rh/NF). To produce current density of 100 mA cm−2, the Rh/NF needed over potential of 263 mV, while the Rh/Ti electrode required only 175 mV. In spite of lower electrical conductivity, caused by the bare Ti foil, the Rh/Ti electrode exhibits superior HER performance. The Tafel slopes of Rh/NF and Rh/Ti electrodes are determined to be 52 and 42 mV dec−1, while the turnover frequencies are estimated to be 1.1 and 37.3 s−1 at over potential of 260 mV.

Characteristics of TiO2 Nanotubes Fabricated by High-Frequency Cyclic Anodization

This study investigates the fabrication of TiO2 nanotubes (TNTs) using the cyclic anodization of Ti foil with high frequency. High-frequency cyclic anodization with increasing duty cycles yields longer, larger, and more regular TNTs, but the walls of the TNTs are thinner. The photocatalytic degradation of methyl orange dye by TNTs indicates that a higher duty cycle during the fabrication of TNTs yields improved performance. For example, the reaction rate constant with a 75% duty cycle (0.0151 ± 0.0003 min−1) is 1.28 times higher than that with a 0% duty cycle (0.0118 ± 0.0018 min−1). It only takes half the time for a 75% duty cycle to reach 70% degradation percentage as compared to, that for the 0% duty cycle. Nevertheless, high-frequency cyclic anodization with increasing duty cycles tends to generate more nanograss on the TNTs and causes a reduction in the TNT strength. Additionally, increasing the duty cycle yields few improvements in the photocurrent and the preferential orientation of anatase TNTs.

Visible light-induced antibacterial and osteogenic cell proliferation properties of hydrogenated TiO2 nanotubes/Ti foil composite

We successfully fabricated the hydrogenated TiO2 nanotubes/Ti foil (H-TNTs/f-Ti) composite via one-step anodization and two-step annealing. H-TNTs/f-Ti composite had a higher visible light-induced photoelectric response and more hydroxyl functional groups compared with Ti foil and unmodified TiO2 nanotubes/Ti foil composite, which contributed to limiting the proliferation of Streptococcus mutans and Porphyromonas gingivalis, promoting the proliferation of MC3T3-E1 cell on the hydroxylated surface, and improving the biocompatibility with osteogenic cells. Our study provides a simple and effective method for significantly improving dental implant efficacy.

Mehanske lastnosti nanostruktur titanovega dioksida

Highly ordered and uniform titanium dioxide (TiO2) nanotubes (NTs) with different morphologies (15 nm, 50 nm and 100 nm in diameter) were prepared by the electrochemical anodization of Ti substrates. The TiO2 NTs’ surface properties were characterized by X-ray diffraction (XRD) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The elastic modulus (E) and the Vickers hardness (HV) of the Ti foil and of the different-morphology TiO2 NTs were evaluated with the nano-indentation technique. E and HV increase with the decreasing length/diameter of the NTs, meaning that NTs with smaller diameters are more resistant to mechanical wear. The elastic modulus of the TiO2 NTs with 15-nm and 50-nm diameters is similar to that of the human bone.

Effects of different interlayers on the microstructure and properties of Mg/Cu dissimilar alloy welded joints

AZ31B Mg alloy and Cu (T2) were combined with different interlayers and laser pulse-welded in the form of lap joints. The microstructure and properties of Mg/Cu dissimilar alloy welded joints of different interlayer materials were studied. The results indicated that the morphology of the welded joint of different interlayer materials were unique. There were cracks in the welded joints of Ti foil and Sn foil. The best welding profile was observed from the Zn foil middle layer, and Cu2Ti and MgZn were formed in Ti and Zn foil welded joints, respectively. The msc marc software was used to simulate the welding temperature and stress of different welded joints. The average thermal stress on the Cu surface was significantly reduced by the different interlayers. The corrosion potential (Ecorr) of the Ti foil welded joint was −0.9111 V, and the corrosion current densities (Icorr) with the Ti foil, Zn foil, and noninterlayer were 32.612, 332.551, and 538.473 μA/cm2, respectively. The corrosion resistance of the welding joints by the Ti foil was the best. The most favorable interlayer was Zn foil, and the shear strength was 48.15 MPa, which was 161% higher than that of the without interlayer welded Mg/Cu joint.

Efficient and Stable Perovskite‐Based Photocathode for Photoelectrochemical Hydrogen Production

AbstractAlthough organometal halide perovskites (OHPs) have desirable photovoltaic properties, their photoelectrochemical (PEC) water‐splitting application for hydrogen production is limited by the instability originating from their intrinsic ionic defects and hygroscopic vulnerability. Herein, a highly efficient and stable OHP‐based photocathode achieved by a new zwitterion (L‐proline) passivation and a eutectic gallium indium alloy (EGaIn) encapsulation method is described. The zwitterion, which has both cations and anions, can simultaneously passivate both positively and negatively charged defects in OHPs. The resulting OHP photovoltaic cells with passivated shows an over 20% power conversion efficiency with an open‐circuit voltage of 1.13 V and a short‐circuit current of 22.13 mA cm−2. The EGaIn‐incorporated Ti foil provides complete encapsulation from the external environment while maintaining good transport of photogenerated charges from OHPs. Thus, these photocathodes exhibit a remarkable average photocurrent density of 21.2 mA cm−2 which has less than 5% current loss between PV cells and PEC cells. More admirably, the photocathode has the highest stability over 54 hours under continuous full sunlight illumination in a sulfuric acid electrolyte.

Preparation and photocatalytic activity of TiO2 nanotube arrays prepared on transparent spinel substrate

TiO2 nanotubes (TNTs) were prepared on transparent spinel (MgAl2O4) ceramic material by anodic oxidation of magnetron sputtered Ti layer. The properties of TNTs were compared with nanotubes produced on other three different substrates, Si wafer, polymeric Kapton film, and Ti foil. The photocatalytic activity of TNTs was tested by the removal of two model pollutants rhodamine B (RhB) and bisphenol A (BPA). Depending on the used substrate, the efficiency of TNTs in the degradation of both pollutants increases in the order of Kapton < spinel < Si < Ti. Nanotubes grown on Ti foil exhibited the best photocatalytic activity reaching 88% for the removal of RhB and 36% for the removal of BPA. The degradation rates of RhB could be well described by the pseudo-first order reaction, while the degradation of BPA could be better fitted with fractional first-order kinetic model. The calculations of residual stresses and deformations in the prepared materials with TNT surface layer showed that the composite with spinel substrate is the most stable structure with minimal warping of the laminate.

Experimental and Numerical Investigations on the Interface Characteristics of Laser Impact-Welded Ti/Brass Joints

The dissimilar welding of metal Ti and alloy brass foils was achieved via laser impact welding. Three laser energies were used, and the interface characteristics of Ti/brass joints were systematically investigated through experiments and smoothed particle hydrodynamics (SPH) simulation. Results indicated that the Ti/brass interfaces under all three laser energies were ring-shaped, and the increase in laser energy resulted in the increase in effective welding area. The phenomena of jet, interface waveform, and cracking were observed at the interface. Jet particles were released from both the Ti flyer and brass target, and interfacial elemental diffusion occurred. SPH simulation results showed that the generation of the interface waveform was related to the collision point position and jet particle ejection direction. The size of the interface waveform increased with the laser energy and increased along the welding direction. This finding was correlated with the horizontal welding velocity, jet velocity, and normal stress. Three different interface failure modes were included in the tensile shear tests, and the maximum tensile force of Ti/brass joints increased with the laser energy.

One-step plasma electrolytic oxidation for TiO2/SnO2 film as LIB anode

ABSTRACTIn this work, a SnO2-doped TiO2 film was rapidly prepared as lithium-ion battery anode by the one-step plasma electrolytic oxidation process on Ti foil. The whole process was carried out in an aqueous solution at room temperature and under atmospheric pressure without any heating or post-treatment. The prepared TiO2/SnO2 composite film exhibited a porous structure with large amounts of channels and cavities, which served as the Li ions diffusion paths and surface active sites for the interfacial electrochemical reactions. The film took full advantage of the high structural stability of TiO2 and a high theoretical capacity of SnO2, showing a high specific capacity (400 mAh g−1 at 100 μA cm−2), an excellent cycling stability (200 cycles), and a good rate capability (capacity reversible after 1000 μA cm−2). This work provides a low-cost and high-efficiency approach for the preparation of binder-free oxide anodes for high-performance LIBs.

Microstructure and mechanical properties of Ti-Ti2AlNb interface

Diffusion bonding of Ti2AlNb alloy using pure titanium (Ti) foil as an interlayer was carried out on superplastic forming and diffusion bonding special equipment by gas pressure loading method. The microstructure of Ti-Ti2AlNb interface was observed using scanning electron microscope and energy-dispersive spectrometer while the mechanical properties of the joints were evaluated by shear test. The results show that the thickness of Ti foil interlayer has a great influence on the microstructure and shear strength of the interface diffusion region. When the thickness of the intermediate layer is thin (25 µm), Ti, aluminum (Al), and niobium (Nb) elements are fully diffused with uniform element distribution through the diffusion region. The diffusion layer region presents uniform, fine, and disordered lamellar α-Ti + β-Ti dual-phase structure with high shear strength. When the thickness of Ti foil interlayer is thick (50 µm), the distribution of Al elements is relatively uniform through the diffusion region due to its smaller radius and faster diffusion speed, and Ti and Nb elements present gradient distribution from the middle to both sides. The diffusion layer region presents a coarse and long strip shape α-Ti + β-Ti dual-phase structure in the middle part and a fine needle-like or irregular α-Ti + β-Ti dual-phase structure in both side parts, with slightly lower shear strength. Temperature has a great influence on the microstructure and mechanical properties of the diffusion bonding joints. The diffusion region presents a black α-Ti strip area in the middle part with the width of about 10 µm at lower temperature (910°C) with poorer property, due to the grain growth of the parent metal, the property is slightly poorer when the temperature is too high (960°C), and the optimal temperature is 930°C with a higher shear strength.

Preparation of ZnO/two-layer self-doped black TiO2 nanotube arrays and their enhanced photochemical properties.

Highly efficient TiO2 photoanodes can be achieved by enhancing electrical conductivity and improving charge separation and transfer. In this paper, Ti foils were used to fabricate TiO2 nanotubes by anodic oxidation and ZnO/two-layer self-doped black TiO2 nanotubes were prepared by electrochemical reduction and a hydrothermal method. The formed black TiO2 nanotubes have a better photoconversion efficiency and the maximum photoconversion efficiency increased by 59% compared with the pure nanotubes. The deposition of ZnO further improves the maximum photoconversion efficiency to 456% based on black TiO2. The photocurrent responses also increase by about 5 times in our results. This work is instructive for the development of highly robust and efficient photoanode materials in fields including photoelectrochemistry and photocatalysis.