Showing papers on "Titanium published in 2012"
TL;DR: This research showed that, while many white-colored products contained titanium, it was not a prerequisite and testing should focus on food-grade TiO(2) (E171) rather than that adopted in many environmental health and safety tests (i.e., P25), which is used in much lower amounts in products less likely to enter the environment.
Abstract: Titanium dioxide is a common additive in many food, personal care, and other consumer products used by people, which after use can enter the sewage system and, subsequently, enter the environment as treated effluent discharged to surface waters or biosolids applied to agricultural land, incinerated wastes, or landfill solids. This study quantifies the amount of titanium in common food products, derives estimates of human exposure to dietary (nano-) TiO(2), and discusses the impact of the nanoscale fraction of TiO(2) entering the environment. The foods with the highest content of TiO(2) included candies, sweets, and chewing gums. Among personal care products, toothpastes and select sunscreens contained 1% to >10% titanium by weight. While some other cremes contained titanium, despite being colored white, most shampoos, deodorants, and shaving creams contained the lowest levels of titanium (<0.01 μg/mg). For several high-consumption pharmaceuticals, the titanium content ranged from below the instrument detection limit (0.0001 μg Ti/mg) to a high of 0.014 μg Ti/mg. Electron microscopy and stability testing of food-grade TiO(2) (E171) suggests that approximately 36% of the particles are less than 100 nm in at least one dimension and that it readily disperses in water as fairly stable colloids. However, filtration of water solubilized consumer products and personal care products indicated that less than 5% of the titanium was able to pass through 0.45 or 0.7 μm pores. Two white paints contained 110 μg Ti/mg while three sealants (i.e., prime coat paint) contained less titanium (25 to 40 μg Ti/mg). This research showed that, while many white-colored products contained titanium, it was not a prerequisite. Although several of these product classes contained low amounts of titanium, their widespread use and disposal down the drain and eventually to wastewater treatment plants (WWTPs) deserves attention. A Monte Carlo human exposure analysis to TiO(2) through foods identified children as having the highest exposures because TiO(2) content of sweets is higher than other food products and that a typical exposure for a US adult may be on the order of 1 mg Ti per kilogram body weight per day. Thus, because of the millions of tons of titanium-based white pigment used annually, testing should focus on food-grade TiO(2) (E171) rather than that adopted in many environmental health and safety tests (i.e., P25), which is used in much lower amounts in products less likely to enter the environment (e.g., catalyst supports, photocatalytic coatings).
1,767 citations
TL;DR: The nonaqueous surfactant-assisted synthesis of highly uniform anatase TiO(2) NCs with tailorable morphology in the 10-100 nm size regime is reported, prepared through a seeded growth technique and the data suggest that the {101} facets of anatase are more active than the {001}.
Abstract: Control over faceting in nanocrystals (NCs) is pivotal for many applications, but most notably when investigating catalytic reactions which occur on the surfaces of nanostructures. Anatase titanium dioxide (TiO2) is one of the most studied photocatalysts, but the shape dependence of its activity has not yet been satisfactorily investigated and many questions still remain unanswered. We report the nonaqueous surfactant-assisted synthesis of highly uniform anatase TiO2 NCs with tailorable morphology in the 10–100 nm size regime, prepared through a seeded growth technique. Introduction of titanium(IV) fluoride (TiF4) preferentially exposes the {001} facet of anatase through in situ release of hydrofluoric acid (HF), allowing for the formation of uniform anatase NCs based on the truncated tetragonal bipyramidal geometry. A method is described to engineer the percentage of {001} and {101} facets through the choice of cosurfactant and titanium precursor. X-ray diffraction studies are performed in conjunction wi...
832 citations
TL;DR: This plasmonic photocatalysis is successfully promoted by sunlight exposure and enables efficient and selective aerobic oxidation of alcohols at ambient temperature.
Abstract: Visible-light irradiation (λ > 450 nm) of gold nanoparticles loaded on a mixture of anatase/rutile TiO2 particles (Degussa, P25) promotes efficient aerobic oxidation at room temperature. The photocatalytic activity critically depends on the catalyst architecture: Au particles with <5 nm diameter located at the interface of anatase/rutile TiO2 particles behave as the active sites for reaction. This photocatalysis is promoted via plasmon activation of the Au particles by visible light followed by consecutive electron transfer in the Au/rutile/anatase contact site. The activated Au particles transfer their conduction electrons to rutile and then to adjacent anatase TiO2. This catalyzes the oxidation of substrates by the positively charged Au particles along with reduction of O2 by the conduction band electrons on the surface of anatase TiO2. This plasmonic photocatalysis is successfully promoted by sunlight exposure and enables efficient and selective aerobic oxidation of alcohols at ambient temperature.
590 citations
TL;DR: The development of a simple solution method to grow non-stoichiometric rutile TiO2 crystals with desired facets is reported, which results in a material exhibiting greatly enhanced photocatalytic H2 production activity relative to the combustion product.
Abstract: The properties and applications of materials are significantly controlled by their physical characteristics, such as size, shape, and structural state. Many processes are governed by interface reactions by which the surface energy and reactivity depend on the spatial configuration, coordination, and structural state of surface atoms and molecules. For crystals, this dependence is directly related to the expression of specific crystallographic faces, which exhibit different surface structures and atomic configurations. These differences explain why some applications, such as molecular adsorption and desorption, gas sensing, drug molecule delivery and release, and heterogeneous catalysis are highly sensitive to the surface atomic structures. Recent progress in the engineering of crystal morphology has included the synthesis of polyhedral silver nanocrystals by the polyol method, the epitaxially seeded growth of highly faceted Pt-Pd nanocrystals, and the controlled overgrowth of Pd-Au core–shell structures enclosed by {111} facets. Apart from these metallic nanocrystals, binary or ternary compounds with preferentially developed facets have also been reported. The facet effect is an important factor for heterogeneous photocatalysts, because surface atom arrangement and coordination intrinsically determine the adsorption of reactant molecules, surface transfer between photoexcited electrons and reactant molecules, and desorption of product molecules. This phenomenon has been well studied in TiO2 photocatalysts. TiO2 is one of the most extensively studied photocatalysts owing to its abundance, nontoxicity, and stability. However, for practical applications, pure TiO2 is not a good candidate because it is only active under ultraviolet (UV) irradiation owing to the band gap of 3.2 eV for the anatase phase. Therefore, band-gap engineering is required to use TiO2 as a water-splitting catalyst under visible-light irradiation. Reduced TiO2 (TiO2 x), containing Ti or O vacancies, has been reported to show visible-light absorption. Various strategies have been applied to synthesize reduced TiO2, such as heating under vacuum [8] or reducing gas, laser irradiation, and high-energy particle bombardment (electrons or Ar ions). A big challenge for the application of reduced TiO2 is that the surface oxygen defects are highly unstable in air owing to the susceptibility of Ti toward oxidation by O2. [13] Recently, we reported a facile one-step combustion method to synthesize partially reduced TiO2. [14] The presence of Ti in the sample extends the photoresponse of TiO2 from the UV to the visible light region, which leads to high visible-light photocatalytic activity for the generation of hydrogen gas from water. However, in the rapid and harsh combustion process, there is very limited control over the crystallization process, which results in the irregularly shaped products. Herein we report the development of a simple solution method to grow non-stoichiometric rutile TiO2 crystals with desired facets. The incorporation of Ti, which extends the light absorption from the UV into the visible range, along with the development of facets with high reactivity, results in a material exhibiting greatly enhanced photocatalytic H2 production activity relative to the combustion product we reported before. Powder X-ray diffraction analysis (Figure 1a) shows that the sample of as-produced TiO2 (sample S1) has rutile structure. All of the diffraction peaks can be assigned to
366 citations
TL;DR: This paper provides an overview of the employment of anodization for nanotubes fabricated on the surface of titanium, titanium alloys and titanium alloying metals such as niobium, tantalum and zirconium metal implants and assesses this topical research to indicate how changes in anodizing conditions influence nanotube characteristics.
345 citations
15 Jan 2012-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, the morphology, microstructure, chemical composition, and hardness of additive manufactured Ti-6Al-4V blocks are investigated and discussed using a Nd:YAG laser.
Abstract: Additive layer manufacturing offers a potential for time and cost savings, especially for aerospace components made from costly titanium alloys. In this paper, the morphology, microstructure, chemical composition, and hardness of additive manufactured Ti-6Al-4V blocks are investigated and discussed. Blocks (7 beads wide, 7 layers high) were deposited using Ti-6Al-4V wire and a Nd:YAG laser. Two different sets of parameters are used and three different post heat treatment conditions (as-built, 600 °C/4 h, 1200 °C/2 h) are investigated. The experiments reveal elementary properties of additive manufactured Ti-6Al-4V material in correlation to process parameters and heat treatments, which are discussed comprehensively.
259 citations
TL;DR: In this paper, the role of oxide dissolution and ionic conduction in the morphological stability of anodic films was examined and it was shown that patterns of pores with a minimum spacing are possible only within a narrow range of the oxide formation efficiency, which should exist when the metal ion charge exceeds two.
Abstract: Electrochemical oxidation of metals, in solutions where the oxide is somewhat soluble, produces anodic oxides with highly regular arrangements of pores. Although porous aluminium and titanium oxides have found extensive use in functional nanostructures, pore initiation and self-ordering are not yet understood. Here we present an analysis that examines the roles of oxide dissolution and ionic conduction in the morphological stability of anodic films. We show that patterns of pores with a minimum spacing are possible only within a narrow range of the oxide formation efficiency (the fraction of oxidized metal atoms retained in the film), which should exist when the metal ion charge exceeds two. Experimentally measured efficiencies, over diverse anodizing conditions on both aluminium and titanium, lie within the different ranges predicted for each metal. On the basis of these results, the relationship between dissolution chemistry and the conditions for pore initiation can now be understood in quantitative terms.
246 citations
TL;DR: Results showed that surfaces treated with HCl–HF–H3PO4 had higher roughness, lower cytotoxicity level and better biocompatibility than controls and addition of calcium chloride into mixed solution of three acids containing HCl, HF and H3 PO4 is an important, predominant and new technique for obtaining biofunction in metals for biomedical use including dentistry.
Abstract: Implant surface topography influences osteoblastic proliferation, differentiation and extracellular matrix protein expressions. Previous researches proved that chemical surface modification of titanium implants could be used to improve Bone-to-implant contact. In this study, the surface topography, chemistry and biocompatibility of polished titanium surfaces treated with mixed solution of three acids containing HCl, HF and H3PO4 with different etched conditions for example concentration, time and addition of calcium chloride were studied. Osteoblast cells (MG-63) were cultured on different groups of titanium surfaces. In order to investigate titanium surfaces, SEM, AFM and EDS analyses were carried out. The results showed that surfaces treated with HCl–HF–H3PO4 had higher roughness, lower cytotoxicity level and better biocompatibility than controls. Moreover, addition of calcium chloride into mixed solution of three acids containing HCl, HF and H3PO4 is an important, predominant and new technique for obtaining biofunction in metals for biomedical use including dentistry.
233 citations
TL;DR: In this in vitro study the physiochemical properties of titanium and zirconia materials were investigated and the affinity of different bacteria to different materials was compared and SFE appears to be the most important factors that determine initial bacterial adhesion to smooth surface.
197 citations
TL;DR: Current literature confirms that TiZr alloys produce small diameter implants with a strength up to 40% higher than conventional, cold-worked, grade IV titanium implants, and with a corrosion resistance and biocompatibility that is at least as good as pure titanium.
Abstract: Dental implants made from binary titanium-zirconium (TiZr) alloys have shown promise as a high strength, yet biocompatible alternative to pure titanium, particularly for applications requiring small diameter implants. The aim of this review is to summarize existing literature reporting on the use of binary TiZr alloys for endosseous dental implant applications as tested in vitro, in animals and clinically. And furthermore to show that TiZr is “at least as good as” pure titanium in terms of biocompatibility and osseointergration. From the twelve papers that met the inclusion criteria, the current literature confirms that TiZr alloys produce small diameter implants with a strength up to 40% higher than conventional, cold-worked, grade IV titanium implants, and with a corrosion resistance and biocompatibility that is at least as good as pure titanium. The surface structure of TiZr is compatible with established surface treatments proven to aid in the osseointegration of titanium implants. Furthermore, binary TiZr alloys have been shown to achieve good osseointegration and high success rates both in animal and in clinical studies.
184 citations
TL;DR: The application of cold plasma may be supportive in the treatment of peri-implant lesions and may improve the process of re-osseointegration.
Abstract: Objectives: Treatment regimens, which predictably support re-osseointegration of implants with peri-implantitis, are needed. Increased wettability may be an important factor for re-osseointegration. In this study, a cold atmospheric pressure gas-discharge plasma was applied to reduce water contact angles on titanium discs with different surface topography and to improve the spreading of osteoblastic cells. Material and Methods: An argon plasma jet with different oxygen admixtures was used to treat titanium discs with different topologies, i.e. machined, SLA ® , SLActive ® , diamond bur-treated or Airflow ® -treated. Water contact angles were measured before and after plasma treatment. The spreading behaviour of human osteoblastic cells was investigated. Results: Contact angle of titanium discs (baseline values: 68°–117°) were significantly reduced close to 0° irrespective of surface topography after the application of argon plasma with 1.0% oxygen admixture for 60 s or 120 s. The cell size of osteoblastic cells grown on argon-oxygen-plasma-treated titanium discs was significantly larger than on non-treated surfaces (p < 0.001) irrespective of surface topography. Conclusions: Plasma treatment reduced contact angle and supported spreading of osteoblastic cells. The application of cold plasma may be supportive in the treatment of peri-implant lesions and may improve the process of re-osseointegration.
TL;DR: XPS analysis confirmed that surface chemistry was altered by both cleaning and sterilization, and indicated that recleaned and resterilized Ti implant surfaces cannot be considered the same as the first surfaces in terms of surface properties and cell responses.
TL;DR: An elementary pattern of the porous structure was designed to mimic the orthotropic properties of the human bone following several mechanical and geometrical criteria and to propose a failure criterion for the design of porous substitutes.
Abstract: Commercially Pure Porous Titanium (CPPTi) can be used for surgical implants to avoid the stress shielding effect due to the mismatch between the mechanical properties of titanium and bone. Most researchers in this area deal with randomly distributed pores or simple architectures in titanium alloys. The control of porosity, pore size and distribution is necessary to obtain implants with mechanical properties close to those of bone and to ensure their osseointegration. The aim of the present work was therefore to develop and characterize such a specific porous structure. First of all, the properties of titanium made by Selective Laser Melting (SLM) were characterized through experimental testing on bulk specimens. An elementary pattern of the porous structure was then designed to mimic the orthotropic properties of the human bone following several mechanical and geometrical criteria. Finite Element Analysis (FEA) was used to optimize the pattern. A porosity of 53% and pore sizes in the range of 860 to 1500 μm were finally adopted. Tensile tests on porous samples were then carried out to validate the properties obtained numerically and identif the failure modes of the samples. Finally, FE elastoplastic analyses were performed on the porous samples in order to propose a failure criterion for the design of porous substitutes.
TL;DR: In this article, the fabrication of open cellular titanium foams by using an innovative spacer through powder metallurgy was investigated, and the porosities and pore structures were investigated by SEM.
TL;DR: In this article, Hierarchical mesoporous nest-like Li 4 Ti 5 O 12 is prepared by a hydrothermal reaction, using CTAB as the surfactant, and water-soluble titanium complex [NH 4 + ] 4 [H + ] 2 [Ti 4 (C 2 H 2 O 3 ) 4 (c 2 H 3 O 3 ), 2 (O 2 ) 4 O 2 ] 6− as the titanium precursor.
TL;DR: The uncoated titanium dioxide was not DNA damaging by the comet assay 24 h after exposure despite being highly inflammogenic, suggesting that inflammation is not a prerequisite to DNA damage in titanium dioxide-based products.
Abstract: Manufactured nanomaterials are projected to be used on a large scale in paints and lacquers. We selected seven commercially interesting materials: Three titanium dioxide-based (two coated rutile; one uncoated anatase), one carbon black (Flamruss 101), one kaolinite clay, and two silica products, whereas carbon black, Printex 90, was used as reference material. DNA damaging activity and inflammogenicity (pulmonary cell composition and mRNAs) were determined 24 h after intratracheal instillation of a single dose of 54 μg in mice. Greatest inflammation was induced by Printex 90 and uncoated titanium dioxide. The inflammatory potency correlated with instilled surface area (R(2) = 0.94) but not with material volume (R(2) = 0.17). The coated titanium dioxides induced DNA damage in lung lining fluid cells. The uncoated titanium dioxide was not DNA damaging by the comet assay 24 h after exposure despite being highly inflammogenic. This suggests that inflammation is not a prerequisite to DNA damage in titanium dioxide-based products.
TL;DR: It is shown that the newly found titanium species is active in the epoxidation reactions in addition to the tetrahedrally coordinated titanium species, however, the acidity of the new titanium species could catalyze the ring-opening reactions of the epoxy products.
Abstract: A thorough investigation of the active titanium species in TS-1 zeolite was conducted by in situ UV resonance Raman spectroscopy combined with UV/Vis diffuse reflectance spectroscopy, DFT calculations, and epoxidation experiments. A new titanium species was identified with a characteristic Raman band at 695 cm-1 when excited at the 266 nm laser line. It is shown that the newly found titanium species is active in the epoxidation reactions in addition to the tetrahedrally coordinated titanium species. However, the acidity of the new titanium species could catalyze the ring-opening reactions of the epoxy products. It results in a lower selectivity toward the epoxy products relative to that of the tetrahedrally coordinated titanium species. The side reaction can be suppressed by the addition of a weak basic reagent.
TL;DR: Superhydrophobic titanium surfaces fabricated by femtosecond laser ablation to mimic the structure of lotus leaves were assessed for their ability to retain coccoid bacteria and each strain was found to preferentially attach to the crevices located between the microscale surface features.
Abstract: Superhydrophobic titanium surfaces fabricated by femtosecond laser ablation to mimic the structure of lotus leaves were assessed for their ability to retain coccoid bacteria. Staphylococcus aureus CIP 65.8T, S. aureus ATCC 25923, S. epidermidis ATCC 14990T and Planococcus maritimus KMM 3738 were retained by the surface, to varying degrees. However, each strain was found to preferentially attach to the crevices located between the microscale surface features. The upper regions of the microscale features remained essentially cell-free. It was hypothesised that air entrapped by the topographical features inhibited contact between the cells and the titanium substratum. Synchrotron SAXS revealed that even after immersion for 50 min, nano-sized air bubbles covered 45% of the titanium surface. After 1 h the number of cells of S. aureus CIP 65.8T attached to the lotus-like titanium increased to 1.27 × 105 mm−2, coinciding with the replacement of trapped air by the incubation medium.
TL;DR: Investigation demonstrated that the synergistic effect in the photocatalytic activity was related to the structure of the sub-micrometer-sized anatase TiO₂ spheres and the significant roles of CNTs in the composite photoc atalysts.
Abstract: The carbon nanotube (CNT)–sub-micrometer-sized anatase TiO2 sphere composite photocatalysts were synthesized by a facile one-step hydrothermal method using titanium tetrafluoride as titanium source and CNTs as structure regulator. Various technologies including X-ray diffraction, UV–visible absorption spectra, N2 adsorption–desorption, scanning electron microscopy, and transmission electron microscopy were employed to characterize the structure properties of the prepared composite photocatalysts. The results indicated that the composite photocatalysts consisted of CNTs wrapping around the sub-micrometer-sized anatase TiO2 spheres with controllable crystal facets and that the aggregated particles with average diameter ranged from 200 to 600 nm. The fabricated composite photocatalysts were used to degrade gaseous styrene in this work. As expected, a synergistic effect that remarkably enhancing the photocatalytic degradation efficiency of gaseous styrene by the prepared composite photocatalysts was observed ...
TL;DR: In this article, the amorphous carbon within the parent OM TiO2-C acted as a rigid support, preventing structural collapse during the conversion process of TiO 2 nanocrystals to TiN carbon, and the OM TiN-C was then successfully applied as counter electrode material in dye-sensitized solar cells.
Abstract: Ordered mesoporous titanium nitride-carbon (denoted as OM TiN-C) nanocomposite with high surface area (389 m2 g–1) and uniform hexagonal mesopores (ca. 5.5 nm) was facilely synthesized via the soft-template method. As a structure-directing agent, Pluronic F127 triblock copolymer formed an ordered structure with inorganic precursors, resol polymer, and prehydrolyzed TiCl4, followed by a successive heating at 700 °C under nitrogen and ammonia flow. In this study, the amorphous carbon within the parent OM TiO2-C acted as a rigid support, preventing structural collapse during the conversion process of TiO2 nanocrystals to TiN nanocrystals. The OM TiN-C was then successfully applied as counter electrode material in dye-sensitized solar cells (DSCs). The organic electrolyte disulfide/thiolate (T2/T–) was introduced to study the electrocatalytic property of the OM TiN-C nanocomposite. Because of the existence of TiN nanocrystals and the defect sites of the amorphous carbon, the DSCs using OM TiN-C as a counter e...
TL;DR: In this article, the authors describe the first systematic comparison and optimisation of extraction methods for titanium dioxide nanoparticles in sunscreen samples, based on sample spiking with aluminium-labeled titanium dioxide reference particles of known size.
Abstract: Titanium dioxide in nanoparticulate form is used in large scale in a variety of consumer products including sunscreens. There is an increasing need for methodology for the reliable characterisation of the particle size and size dependent elemental composition in these complex matrices. Such measurement capability is essential for underpinning safety assessments, for quality control of existing products and for correlation of nanoparticle characteristics with biological effects observed in toxicity tests. This work describes the first systematic comparison and optimisation of extraction methods for titanium dioxide nanoparticles in sunscreen samples. Sunscreens were selected because of their wide use, high fat content and matrix of high complexity. Defatting of the sample with hexane followed by bath sonication with an aqueous extractant was found to provide stable suspensions of secondary titanium dioxide particles for their size characterisation by flow field flow fractionation on-line with element selective detection by inductively coupled plasma mass spectrometry. Further addition of a small amount of hexane to the aqueous extractant resulted in particle disaggregation and thus allowed for characterisation of the primary particle size. A novel approach based on sample spiking with aluminium-labelled titanium dioxide reference particles of known size was used to study the effect of extraction and separation conditions on particle size distribution in the presence of the real sample matrix. The developed methodology was applied to analysis of commercial sunscreens with various sun protection factors. Titanium extraction efficiency, particle size distribution and titanium dioxide recovery from the FFF channel were determined for each product.
TL;DR: In this paper, a Ti-6Al-4V alloy was bonded to electrolytic copper at various temperatures of 875, 890 and 900°C and times of 15, 30 and 60 min through diffusion bonding.
TL;DR: An overview of surface treatment methods, including coating with hydroxyapatite (HAp), an osteoconductive compound, is outlined, and evaluation by implantation of surface-modified samples in rat tibiae is described.
Abstract: Many techniques for the surface modification of titanium and its alloys have been proposed from the viewpoint of improving bioactivity. This paper contains an overview of surface treatment methods, including coating with hydroxyapatite (HAp), an osteoconductive compound. There are two types of coating methods: pyroprocessing and hydroprocessing. In this paper, hydroprocessing for coating on the titanium substrate with HAp, carbonate apatite (CO3–Ap), a CO3–Ap/CaCO3 composite, HAp/collagen, and a HAp/gelatin composite is outlined. Moreover, evaluation by implantation of surface-modified samples in rat tibiae is described.
TL;DR: In this paper, the degradation of titanium-based oral rehabilitation systems can occur by corrosion and wear processes taking place simultaneously (tribocorrosion) and influenced by the presence of fluorides.
TL;DR: In this paper, a quaternary Ti-20Nb-10Zr-5Ta alloy with β-near microstructure was obtained and its native passive film composition and its modification and corrosion resistance after 2000 immersion hours in simulated biofluids were studied.
TL;DR: In this article, a pure titanium matrix composite reinforced with carbon nanotubes (CNTs) was prepared by spark plasma sintering and hot extrusion via powder metallurgy process.
TL;DR: The obtained Ti(n)O(2n-1) (n = 2, 3, 4, 6) macroporous monoliths could find applications as electrodes for many electrochemical reactions.
Abstract: Monolithic conductive titanium oxides Ti(n)O(2n-1) (n = 2, 3, 4, 6) with well-defined macropores have been successfully prepared as a single phase, via reduction of a macroporous TiO(2) precursor monolith using zirconium getter. Despite substantial removal of oxide ions, all the reduced monoliths retain the macropore properties of the precursor, i.e., uniform pore size distribution and pore volume. Furthermore, compared to commercial porous Ebonex (shaped conductive Ti(n)O(2n-1)), the bulk densities (1.8 g cm(-3)) are half, and the porosities (60%) are about 3 times higher. The obtained Ti(n)O(2n-1) (n = 2, 3, 4, 6) macroporous monoliths could find applications as electrodes for many electrochemical reactions.
TL;DR: In this article, the effects of the carbon-nanotube content on phase composition, microstructure, micro-hardness and dry sliding wear resistance of the TiC reinforced Ti matrix composite layers were fabricated by laser cladding.
TL;DR: This kind of porous metal-entangled titanium wire material is very promising for implant applications because of their very good toughness, perfect flexibility, high strength, adequate elastic modulus, and low cost.
Abstract: A kind of porous metal-entangled titanium wire material has been investigated in terms of the pore structure (size and distribution), the strength, the elastic modulus, and the mechanical behavior under uniaxial tensile loading. Its functions and potentials for surgical application have been explained. In particular, its advantages over competitors (e.g., conventional porous titanium) have been reviewed. In the study, a group of entangled titanium wire materials with non-woven structure were fabricated by using 12–180 MPa forming pressure, which have porosity in a range of 48%–82%. The pores in the materials are irregular in shape, which have a nearly half-normal distribution in size range. The yield strength, ultimate tensile strength, and elastic modulus are 75 MPa, 108 MPa, and 1.05 GPa, respectively, when its porosity is 44.7%. The mechanical properties decrease significantly as the porosity increases. When the porosity is 57.9%, these values become 24 MPa, 47.5 MPa, and 0.33 GPa, respectively. The low elastic modulus is due to the structural flexibility of the entangled titanium wire materials. For practical reference, a group of detailed data of the porous structure and the mechanical properties are reported. This kind of material is very promising for implant applications because of their very good toughness, perfect flexibility, high strength, adequate elastic modulus, and low cost.
TL;DR: A simple single-stage approach, based on the hydrothermal technique, has been introduced to synthesize reduced graphene oxide/titanium dioxide nanocomposites, which enhanced the electrochemical performance compared to a conventional glassy carbon electrode when interacting with mercury(II) ions in potassium chloride electrolyte.
Abstract: A simple single-stage approach, based on the hydrothermal technique, has been introduced to synthesize reduced graphene oxide/titanium dioxide nanocomposites. The titanium dioxide nanoparticles are formed at the same time as the graphene oxide is reduced to graphene. The triethanolamine used in the process has two roles. It acts as a reducing agent for the graphene oxide as well as a capping agent, allowing the formation of titanium dioxide nanoparticles with a narrow size distribution (~20 nm). Transmission electron micrographs show that the nanoparticles are uniformly distributed on the reduced graphene oxide nanosheet. Thermogravimetric analysis shows the nanocomposites have an enhanced thermal stability over the original components. The potential applications for this technology were demonstrated by the use of a reduced graphene oxide/titanium dioxide nanocomposite-modified glassy carbon electrode, which enhanced the electrochemical performance compared to a conventional glassy carbon electrode when interacting with mercury(II) ions in potassium chloride electrolyte.