Showing papers on "Titanium published in 2015"
TL;DR: It may be said that the NiS/Pt/Ti counter electrode is a promising catalytic material to replace the expensive platinum in FDSSCs.
Abstract: A composite film of nickel sulfide/platinum/titanium foil (NiS/Pt/Ti) with low cost and high electrocatalytic activity was synthesized by the use of an in situ electropolymerization route and proposed as a counter electrode (CE) catalyst for flexible dye-sensitized solar cells (FDSSCs). The FDSSC with the NiS/Pt/Ti CE exhibited a comparable power conversion efficiency of 7.20% to the FDSSC with the platinum/titanium (Pt/Ti) CE showing 6.07%. The surface morphology of the NiS/Pt/Ti CE with one-dimensional (1D) structure is characterized by using the scanning electron microscopy (SEM). The NiS/Pt/Ti CE also displayed multiple electrochemical functions of excellent conductivity, great electrocatalytic ability for iodine/triiodine, and low charge transfer resistance of 2.61 ± 0.02 Ω cm2, which were characterized by using the cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Tafel polarization plots. The photocurrent-photovoltage (J-V) character curves were further used to calculate the theoretical optical light performance parameters of the FDSSCs. It may be said that the NiS/Pt/Ti counter electrode is a promising catalytic material to replace the expensive platinum in FDSSCs.
1,036 citations
TL;DR: The design of sub-10 nm rutile titanium dioxide nanoparticles, with an increased amount of surface/sub-surface defects to overcome the negative effects from bulk defects to enhance, rather than initiate, the visible-light-driven water splitting.
Abstract: Titanium dioxide is a promising photocatalyst for water splitting, but it suffers from low visible light activity due to its wide band gap Doping can narrow the band gap of titanium dioxide; however, new charge-carrier recombination centres may be introduced Here we report the design of sub-10 nm rutile titanium dioxide nanoparticles, with an increased amount of surface/sub-surface defects to overcome the negative effects from bulk defects Abundant defects can not only shift the top of the valence band of rutile titanium dioxide upwards for band-gap narrowing but also promote charge-carrier separation The role of titanium(III) is to enhance, rather than initiate, the visible-light-driven water splitting The sub-10 nm rutile nanoparticles exhibit the state-of-the-art activity among titanium dioxide-based semiconductors for visible-light-driven water splitting and the concept of ultra-small nanoparticles with abundant defects may be extended to the design of other robust semiconductor photocatalysts
664 citations
TL;DR: The use of sustainable metal-based catalysts for the synthesis of five-membered ring containing cyclic carbonates from epoxides and carbon dioxide is critically reviewed in this article, which is restricted to catalysis by the abundant metals: sodium, potassium, aluminium, calcium, titanium and iron.
509 citations
TL;DR: Overall, published studies indicated that an acid etched surface-modified and a coating application on commercial pure titanium implant was most preferable in producing the good surface roughness and mechanical properties of titanium could lead to successful dental implants.
Abstract: This review covers several basic methodologies of surface treatment and their effects on titanium (Ti) implants. The importance of each treatment and its effects will be discussed in detail in order to compare their effectiveness in promoting osseointegration. Published literature for the last 18 years was selected with the use of keywords like titanium dental implant, surface roughness, coating, and osseointegration. Significant surface roughness played an important role in providing effective surface for bone implant contact, cell proliferation, and removal torque, despite having good mechanical properties. Overall, published studies indicated that an acid etched surface-modified and a coating application on commercial pure titanium implant was most preferable in producing the good surface roughness. Thus, a combination of a good surface roughness and mechanical properties of titanium could lead to successful dental implants.
400 citations
TL;DR: Perhaps the most spectacular and surprising one-dimensional structures and their unique biomedical applications for increased osseointegration, protein interaction and antibacterial properties are focused on.
Abstract: Titanium and titanium alloys exhibit a unique combination of strength and biocompatibility, which enables their use in medical applications and accounts for their extensive use as implant materials in the last 50 years. Currently, a large amount of research is being carried out in order to determine the optimal surface topography for use in bioapplications, and thus the emphasis is on nanotechnology for biomedical applications. It was recently shown that titanium implants with rough surface topography and free energy increase osteoblast adhesion, maturation and subsequent bone formation. Furthermore, the adhesion of different cell lines to the surface of titanium implants is influenced by the surface characteristics of titanium; namely topography, charge distribution and chemistry. The present review article focuses on the specific nanotopography of titanium, i.e. titanium dioxide (TiO2) nanotubes, using a simple electrochemical anodisation method of the metallic substrate and other processes such as the hydrothermal or sol-gel template. One key advantage of using TiO2 nanotubes in cell interactions is based on the fact that TiO2 nanotube morphology is correlated with cell adhesion, spreading, growth and differentiation of mesenchymal stem cells, which were shown to be maximally induced on smaller diameter nanotubes (15 nm), but hindered on larger diameter (100 nm) tubes, leading to cell death and apoptosis. Research has supported the significance of nanotopography (TiO2 nanotube diameter) in cell adhesion and cell growth, and suggests that the mechanics of focal adhesion formation are similar among different cell types. As such, the present review will focus on perhaps the most spectacular and surprising one-dimensional structures and their unique biomedical applications for increased osseointegration, protein interaction and antibacterial properties.
395 citations
TL;DR: In this paper, a simple and straightforward technique for the investigation of the formation of an interfacial reaction zone (interphase) at the surface of a solid electrolyte is presented.
374 citations
TL;DR: In this paper, it is shown that anatase TiO2 exhibits a behavior similar to the more frequently investigated lithium-ion chemistry, however, there are great, and rather surprising, differences, at least in the case of anataseTiO2.
Abstract: It is frequently assumed that sodium-ion battery chemistry exhibits a behavior that is similar to the more frequently investigated lithium-ion chemistry. However, in this work it is shown that there are great, and rather surprising, differences, at least in the case of anatase TiO2. While the generally more reducing lithium ion is reversibly inserted in the anatase TiO2 lattice, sodium ions appear to partially reduce the rather stable oxide and form metallic titanium, sodium oxide, and amorphous sodium titanate, as revealed by means of in situ X-ray diffraction, ex situ X-ray photoelectron spectroscopy, scanning electron microscopy, and Raman spectroscopy. Nevertheless, once the electrochemical transformation of anatase TiO2 is completed, the newly formed material presents a very stable long-term cycling performance, excellent high rate capability, and superior coulombic efficiency, highlighting it as a very promising anode material for sodium-ion battery applications.
302 citations
TL;DR: Bacterial adhesion on titanium-substrates used for bone implants is examined, with results suggesting the dominant effects of the macroscopic surface topography, as well as microasperity at the surface roughness scale, which were produced during titanium machining, HT treatment, or both.
Abstract: This study examines bacterial adhesion on titanium-substrates used for bone implants. Adhesion is the most critical phase of bacterial colonization on medical devices. The surface of titanium was m...
253 citations
TL;DR: In this paper, the influence of the electrolyte, process parameters, pretreatment and post-treatment on the coating characteristics (surface micrograph, adhesion strength and biological compatibility etc.) is detailed.
243 citations
TL;DR: In this paper, the authors report the response of bacteria and primary human fibroblasts to the antibacterial nanoarrays fabricated on titanium surfaces using a simple hydrothermal etching process.
Abstract: Titanium and its alloys remain the most popular choice as a medical implant material because of its desirable properties. The successful osseointegration of titanium implants is, however, adversely affected by the presence of bacterial biofilms that can form on the surface, and hence methods for preventing the formation of surface biofilms have been the subject of intensive research over the past few years. In this study, we report the response of bacteria and primary human fibroblasts to the antibacterial nanoarrays fabricated on titanium surfaces using a simple hydrothermal etching process. These fabricated titanium surfaces were shown to possess selective bactericidal activity, eliminating almost 50% of Pseudomonas aeruginosa cells and about 20% of the Staphylococcus aureus cells coming into contact with the surface. These nano-patterned surfaces were also shown to enhance the aligned attachment behavior and proliferation of primary human fibroblasts over 10 days of growth. These antibacterial surfaces, which are capable of exhibiting differential responses to bacterial and eukaryotic cells, represent surfaces that have excellent prospects for biomedical applications.
220 citations
TL;DR: Overall, this study shows that the nanostructured surface improved the osseointegration of titanium implants and may be an alternative to conventional grit-blasted and acid-etched surface treatments.
TL;DR: In this article, a novel preparation method for crystalline, thermally stable (up to 800 °C) TiO2 materials with tunable anatase/rutile phase compositions (0-100%) and monomodal mesoporosity was reported.
Abstract: The high photocatalytic activity of mixed phase (80% anatase and 20% rutile) titanium dioxide (Degussa P25) has attracted a great deal of interest in recent years. However, its low efficiency in visible light and nonporous nature limits the potential use and capabilities. Here, we report a novel preparation method for crystalline, thermally stable (up to 800 °C) TiO2 materials with tunable anatase/rutile phase compositions (0–100%) and monomodal mesoporosity. The control of the phase compositions was achieved by framework vanadium doping and various applied heat treatments. Vanadium (0% to 10% doping) decreased the anatase–rutile transformation temperature (from 1000 to 600 °C) and shifted the absorption band to the visible light region (narrowed the band gap). The mesopore structure was preserved in mixed phase TiO2. These materials are members of the recently discovered University of Connecticut (UCT) mesoporous materials family. The UCT materials are randomly packed nanoparticle aggregates and mesopore...
TL;DR: In this article, hierarchical WO 3 -TiO 2 nanotubes (WTNs) composite structures were obtained by anodization of titanium in a single-step process using sodium tungstate as the tungsten source.
TL;DR: T titanium implants that release copper ions can be effective against bacterial infections at higher concentrations of copper near the implant surface and can promote bone regeneration when its concentration becomes lower due to diffusion.
TL;DR: In this article, multi-walled carbon nanotube (MWCNT) reinforced titanium matrix composites were synthesized using a spark plasma sintering method at a low sinting temperature of 550 degrees C. The effects of the weight fraction of MWCNTs on the microstructures and the mechanical and thermal properties of the composites are investigated.
TL;DR: It is shown here, using in situ transmission electron microscopy straining experiments, that plasticity proceeds very differently in these two metals, being intermittent in Ti and continuous in Zr.
Abstract: Despite similarities in crystallography and electronic structure in titanium and zirconium, it is shown that plasticity proceeds differently between the two, associated with differing dislocation configuration stability.
TL;DR: In this paper, the photocatalytic reduction of exfoliated graphene oxide (GO) by TiO2 (Evonik P25) under UV irradiation in the presence of methanol as a hole acceptor was investigated.
TL;DR: This study shows that TiS3 is a competitive electronic material in the family of two-dimensional (2D) transition metal chalcogenides and can be considered for emerging device applications.
Abstract: Titanium trisulfide (TiS3) is a promising layered semiconductor material. Several-mm-long TiS3 whiskers can be conveniently grown by the direct reaction of titanium and sulfur. In this study, we exfoliated these whiskers using the adhesive tape approach and fabricated few-layered TiS3 field-effect transistors (FETs). The TiS3 FETs showed an n-type electronic transport with room-temperature field-effect mobilities of 18–24 cm2 V−1 s−1 and ON/OFF ratios up to 300. We demonstrate that TiS3 is compatible with the conventional atomic layer deposition (ALD) procedure for Al2O3. ALD of alumina on TiS3 FETs resulted in mobility increase up to 43 cm2 V−1 s−1, ON/OFF ratios up to 7000, and much improved subthreshold swing characteristics. This study shows that TiS3 is a competitive electronic material in the family of two-dimensional (2D) transition metal chalcogenides and can be considered for emerging device applications.
TL;DR: In this paper, the deformation mechanism during machining of titanium alloys is complex and causes basic challenges, such as sawtooth chips, high temperature, high stress on cutting tool, high tool wear and undercut parts.
Abstract: This article correlates laboratory-based understanding in machining of titanium alloys with the industry based outputs and finds possible solutions to improve machining efficiency of titanium alloy Ti-6Al-4V. The machining outputs are explained based on different aspects of chip formation mechanism and practical issues faced by industries during titanium machining. This study also analyzed and linked the methods that effectively improve the machinability of titanium alloys. It is found that the deformation mechanism during machining of titanium alloys is complex and causes basic challenges, such as sawtooth chips, high temperature, high stress on cutting tool, high tool wear and undercut parts. These challenges are correlated and affected by each other. Sawtooth chips cause variation in cutting forces which results in high cyclic stress on cutting tools. On the other hand, low thermal conductivity of titanium alloy causes high temperature. These cause a favorable environment for high tool wear. Thus, impr...
TL;DR: The results show that porous Ti6Al4V ELI still remains the strongest material for statically loaded applications, whereas pure titanium has a mechanical behavior similar to tantalum and is the material of choice for cyclically loaded porous implants.
TL;DR: A review of the effects of voltage, time and electrolytes on a calcium phosphate-base composite layer in case of pure titanium and other biomedical grade titanium alloys via the plasma electrolytic oxidation (PEO) method aims at the further development of PEO by producing more adequate titanium-base implants along with desired mechanical and biomedical features.
TL;DR: An attempt was made to produce a bone-compatible metastable β-type Ti-33Nb-4Sn (wt. %) alloy with ultralow Young’s modulus (36’GPa, versus ~30 GPa for human bone) and high ultimate strength (853 MPa) and it is believed that this method can be applied to developing advanced metastableβ-type titanium alloys for implant applications.
Abstract: Titanium and its alloys have become the most attractive implant materials due to their high corrosion resistance, excellent biocompatibility and relatively low elastic modulus. However, the current Ti materials used for implant applications exhibit much higher Young’s modulus (50 ~ 120 GPa) than human bone (~30 GPa). This large mismatch in the elastic modulus between implant and human bone can lead to so-called “stress shielding effect” and eventual implant failure. Therefore, the development of β-type Ti alloys with modulus comparable to that of human bone has become an ever more pressing subject in the area of advanced biomedical materials. In this study, an attempt was made to produce a bone-compatible metastable β-type Ti alloy. By alloying and thermo-mechanical treatment, a metastable β-type Ti-33Nb-4Sn (wt. %) alloy with ultralow Young’s modulus (36 GPa, versus ~30 GPa for human bone) and high ultimate strength (853 MPa) was fabricated. We believe that this method can be applied to developing advanced metastable β-type titanium alloys for implant applications. Also, this approach can shed light on design and development of novel β-type titanium alloys with large elastic limit due to their high strength and low elastic modulus.
TL;DR: Electrochemical impedance spectroscopy, open circuit potential (OCP) and potentiodynamic polarization tests were associated to advanced characterization techniques such as SEM, EDS, AFM, ICP-MS and XPS, revealing a higher reactivity of both CP titanium and Ti6Al4V at 12,300 ppm F(-) concentration than that recorded at 227 ppm F(-).
TL;DR: A blue shift of the photoluminescence spectra reveals that the defects of under-coordinated Ti3+ ions transform to surface oxygen vacancies in the anatase TiO2 film annealing at temperature from 800°C to 900°C in N2 atmosphere.
Abstract: TiO2 films were grown on silicon substrates by atomic layer deposition (ALD) using tetrakis-dimethylamino titanium and ozone. Amorphous TiO2 film was deposited at a low substrate temperature of 165°C, and anatase TiO2 film was grown at 250°C. The amorphous TiO2 film crystallizes to anatase TiO2 phase with annealing temperature ranged from 300°C to 1,100°C in N2 atmosphere, while the anatase TiO2 film transforms into rutile phase at a temperature of 1,000°C. Photoluminescence from anatase TiO2 films contains a red band at 600 nm and a green band at around 515 nm. The red band exhibits a strong correlation with defects of the under-coordinated Ti3+ ions, and the green band shows a close relationship with the oxygen vacancies on (101) oriented anatase crystal surface. A blue shift of the photoluminescence spectra reveals that the defects of under-coordinated Ti3+ ions transform to surface oxygen vacancies in the anatase TiO2 film annealing at temperature from 800°C to 900°C in N2 atmosphere.
TL;DR: In this article, the photocatalytic activity of copper-decorated WO3-TiO2 nanotubes (Cu/WTNs) was investigated by anodizing and photochemical deposition.
TL;DR: The improvement of the mechanical properties of modifiedTi G4 means that Ti G5 can be safely replaced by Ti G4 Hard without compromising the fracture resistance, with the advantage of not releasing toxic ions.
TL;DR: In this article, the improved properties of graphene-based coatings in respect to the graphene-free coatings, as a consequence of toughening action of graphene, were demonstrated: reduced surface cracks, better mechanical resistance, and enhanced thermal stability.
TL;DR: In this article, a series of metal sulfides have been used to sensitize titanium metal-organic frameworks to form heterostructures through a facile photodeposition strategy.
Abstract: A series of metal sulfides have been used to sensitize titanium metal–organic frameworks to form heterostructures through a facile photodeposition strategy. Graphene-like MoS2 sheets, Ag2S, CdS and CuS quantum dots were uniformly deposited onto MIL-125(Ti) under ultraviolet light conditions. The as-obtained heterostructure hybrids exhibited interesting photocatalytic activity for Cr(VI) reduction under visible light irradiation.
TL;DR: It is demonstrated that the surface morphology and roughness at the nanoscale level substantially affect the titanium dioxide surface-water droplet interaction, opposing to previous observations for microscale structured surfaces.
TL;DR: The potential of titanium incorporation into cupric oxide (CuO) is demonstrated in this paper, where it is shown that Ti doped CuO reduces sheet resistance and improved the charge transport properties.