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Showing papers on "Titanium published in 2006"


Journal ArticleDOI
TL;DR: An overview of titanium alloy use for medical devices, their current status, future opportunities and obstacles for expanded application is provided in this article, which is divided into three main sections, the first discussing recent efforts focused on commercial purity titanium.

913 citations


Journal ArticleDOI
TL;DR: In this in vitro study, a novel surface modification was tested to improve the initial wettability and to retain SLA microstructure and shows increased surface free energy (SFE) and increased hydrophilicity with initial water contact angles of 0 degrees compared to 139.9 degrees for SLA.
Abstract: Roughness-induced hydrophobicity, well-known from natural plant surfaces and intensively studied toward superhydrophobic surfaces, has currently been identified on microstructured titanium implant surfaces. Studies indicate that microstructuring by sandblasting and acid etching (SLA) enhances the osteogenic properties of titanium. The undesired initial hydrophobicity, however, presumably decelerates primary interactions with the aqueous biosystem. To improve the initial wettability and to retain SLA microstructure, a novel surface modification was tested. This modification differs from SLA by its preparation after acid etching, which was done under protective gas conditions following liquid instead of dry storage. We hypothesized that this modification should have increased wettability due to the prevention of contaminations that occurs during air contact. The main outcome of dynamic wettability measurements was that the novel modification shows increased surface free energy (SFE) and increased hydrophilicity with initial water contact angles of 0° compared to 139.9° for SLA. This hydrophilization was kept even after any drying. Reduced hydrocarbon contaminations were identified to play a possible role in altered surface thermodynamics. Such surfaces aim to retain the hydrophilicity and natural high surface energy of the Ti dioxide surface until surgical implants' insertion and are compared in this in vitro study with structural surface variants of titanium to compare roughness and chemically induced wettability. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006

593 citations


Journal ArticleDOI
TL;DR: The photoluminescence of both kinds of particles (anatase and rutile) with several well-resolved peaks extending in the visible spectral region was observed, and the quantum yield at room temperature was found to be 0.25%.
Abstract: Nonaqueous reactions between titanium(IV) chloride and alcohols (benzyl alcohol or n-butanol) were used for the synthesis of anatase TiO2 particles, while rutile TiO2 particles were synthesized in aqueous media by acidic hydrolysis of titanium(IV) chloride. The X-ray diffraction measurements proved the exclusive presence of either the anatase or the rutile phase in prepared samples. The photoluminescence of both kinds of particles (anatase and rutile) with several well-resolved peaks extending in the visible spectral region was observed, and the quantum yield at room temperature was found to be 0.25%. Photon energy up-conversion from colloidal anatase and rutile TiO2 particles was observed at low excitation intensities. The energy of up-converted photoluminescence spans the range of emission of normal photoluminescence. The explanation of photon energy up-conversion involves mid-gap energy levels originating from oxygen vacancies.

387 citations


Journal ArticleDOI
01 Oct 2006-Carbon
TL;DR: In this paper, high surface area nanoporous carbon has been prepared by thermo-chemical etching of titanium carbide TiC in chlorine in the temperature range 200-1200-C. Structural analysis showed that this carbide-derived carbon was highly disordered at all synthesis temperatures.

376 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of the elements on physical phenomena such as laser absorption, heat transfer, wetting and spreading of the melt, oxidation, Rayleigh instability and Marangoni convection was investigated.

354 citations


Journal ArticleDOI
TL;DR: To investigate the influence of titanium films with nanometre scale topography on protein adsorption and cell growth, three different model titanium films were utilized in the present study.

342 citations


Journal ArticleDOI
TL;DR: The results show that neither zinc or titanium ions nor microfine zinc oxide or titanium dioxide particles were able to penetrate porcine stratum corneum, and it is concluded that their use in sunscreens does not pose a health risk.

335 citations


Journal ArticleDOI
TL;DR: The working group concluded that the epidemiological studies of carbon black provided inadequate evidence of carcinogenicity, and no clear dose-response relation between exposure to carbon black and lung cancer was noted.
Abstract: In February, 2006, 19 scientists from eight countries met at the International Agency for Research on Cancer (IARC), Lyon, France, to reassess the carcinogenicity of carbon black, titanium dioxide, and non-asbestiform talc. These assessments will be published as volume 93 of the IARC Monographs, and are the fi rst assessments since the IARC Monograph preamble was amended. All three of the above agents are poorly soluble particles that are weakly toxic, and were chosen for assessment because evidence suggests that they cause cancer in the respiratory tract of rats through similar mechanisms: after exposure to high concentrations of these agents, deposition of particles onto the respiratory epithelium can lead to enhanced particle retention, impaired lung clearance, infl ammatory response, production of reactive oxygen species, cell injury, cell proliferation, fi brosis, induction of mutations, and, ultimately, cancer. Because many of these steps arise in people who work in dusty environments (eg, coal miners), data on cancer in animals obtained in conditions of impaired lung clearance could be relevant to human beings. Furthermore, impaired lung clearance and adverse eff ects in the lungs of rats that have been exposed to ultrafi ne particles (<100 nm) occur at much lower mass concentrations than in rats exposed to fi ne particles (<10 μm), increasing the potential relevance to human beings. Carbon black is a particulate form of elemental carbon. About 90% of carbon black is used in rubber products, mainly tyres. Carbon black is also used as a pigment in inks, paints and coatings, and in plastics. Exposure to carbon-black particles occurs mainly in the form of aggregates (ie, particle size, 50−600 nm) and agglomerates (227 μm). Most types of carbon black have small quantities (ie, <1%) of organic compounds, including polycyclic aromatic hydrocarbons, adsorbed onto their surface. The highest exposures to carbon black arise during its manufacturing. Exposure in industries that use carbon black is diffi cult to assess because data are scarce. No substantial exposure to carbon black is thought to occur when it is bound to other materials such as rubber, printing ink, or paint. Workers who produced carbon black in Germany and the UK had an excess risk of lung cancer. Confounding by smoking was unlikely to explain the entire excess risk, but no clear dose-response relation between exposure to carbon black and lung cancer was noted. A US study of workers in carbon black production found no excess risk of lung cancer, but no data according to level of exposure were reported. A study of workers in the rubber industry in Germany who were exposed to carbon black showed no signifi cant excess risk of lung cancer after adjustment for potential confounding by asbestos and talc. The working group concluded that the epidemiological studies of carbon black provided inadequate evidence of carcinogenicity. Carbon black and its extracts have been tested in rats and mice by inhalation, intratracheal instillation, dermal application, and subcutaneous injection. The overall results provided suffi cient evidence in laboratory animals for the carcinogenicity of carbon black and carbon-black extracts. The working group classifi ed carbon black as possibly carcinogenic to human beings (ie, group 2B). Titanium dioxide accounts for 70% of the total production volume of pigments worldwide. The primary particles are typically 200–300 nm in diameter, but larger aggregates and agglomerates are formed readily. Ultrafi ne grades of titanium dioxide (ie, 10–50 nm) are used in sunscreens and plastics to block ultraviolet light, and in catalysts. Highest expo sures occur in titanium-dioxide produc tion during packing, milling, site cleaning, and maintenance. Exposure data for industries that use titanium dioxide are scarce. The largest epidemiological cohort study considered included workers in the titanium dioxide production industry in six European countries, and showed a small but signifi cant increase in risk of lung cancer compared with that for the general population; however, the data did not suggest an exposure-response relation. Two cohort studies undertaken in the USA did not report excess risks of lung cancer, neither did a Canadian population-based casecontrol study. Overall, the working group concluded that the epidemiological studies on titanium dioxide provide inadequate evidence of carcinogenicity. Pigment-grade titanium dioxide and ultrafi ne titanium dioxide have been tested in rats, mice, and hamsters by various routes of administration. Overall, results from studies of inhalation and intratracheal instillation provided suffi cient evidence in animals for the carcinogenicity of titanium dioxide. The working group classifi ed titanium dioxide as possibly carcinogenic to human beings (ie, group 2B). Talc refers to both mineral talc and industrial products that contain 35% to >95% mineral talc. Mineral talc Upcoming meetings

299 citations


Journal ArticleDOI
TL;DR: In this paper, a set of available experimental data on the binding energies of Ti 2p3/2 and O 1s core levels in titanium-bearing oxides has been presented by using the binding energy difference (O 1s−Ti 2p 3/2) as a robust parameter to characterize these compounds.

278 citations


Journal ArticleDOI
TL;DR: In this article, the selective laser melting (SLM) process has been used to produce metallic parts directly from powder material using CAD data, and the die for metal forming from the nickel-based alloy and the pure titanium models of bone and dental crown is demonstrated.
Abstract: In order to produce metallic parts directly from powder material using CAD data, the selective laser melting (SLM) process has been developed. From a series of material tests, nickel-based alloy, Fe alloy and pure titanium powders are found to be feasible for fabrication of metallic models by SLM. Finite element simulation shows stress distribution within the solid single layer formed on the powder bed during forming and some methods for avoiding defects in the products are suggested. The die for metal forming from the nickel-based alloy and the pure titanium models of bone and dental crown are demonstrated. The density of the model made by SLM is higher than 90% of the solid model. The mechanical properties of the formed model can be improved to those of the solid by post-processing.

278 citations


Journal ArticleDOI
TL;DR: Due to similar mechanical performance when compared to pure titanium, the TiAg coatings should be suitable to provide antimicrobial activity on load-bearing implant surfaces and showed significant antimicrobial potency against Staphylococcus epidermis and Klebsiella pneumoniae strains.
Abstract: Biofilm formation and deep infection of endoprostheses is a recurrent complication in implant surgery. Post-operative infections may be overcome by adjusting antimicrobial properties of the implant surface prior to implantation. In this work we described the development of an antimicrobial titanium/silver hard coating via the physical vapor deposition (PVD) process. Coatings with a thickness of approximately 2 μm were deposited on titanium surfaces by simultaneous vaporisation of both metals in an inert argon atmosphere with a silver content of approximately 0.7 – 9% as indicated by energy dispersive X-ray analysis. On these surfaces microorganisms and eukaryotic culture cells were grown. The coatings released sufficient silver ions (0.5–2.3 ppb) when immersed in PBS and showed significant antimicrobial potency against Staphylococcus epidermis and Klebsiella pneumoniae strains. At the same time, no cytotoxic effects of the coatings on osteoblast and epithelial cells were found. Due to similar mechanical performance when compared to pure titanium, the TiAg coatings should be suitable to provide antimicrobial activity on load-bearing implant surfaces.

Journal ArticleDOI
TL;DR: Tubes annealed to anatase, or a mixture of anatase and rutile are clearly more efficient in promoting apatite formation than the tubes in their "as-formed" amorphous state.
Abstract: In the present work, we study the growth of hydroxyapatite formation on different TiO(2) nanotube layers. The nanotube layers were fabricated by electrochemical anodization of titanium in fluoride-containing electrolytes. To study various nanotube lengths, layers with an individual tube diameter of 100 nm were grown to a thickness of approximately 2 mum or 500 nm. The ability to form apatite on the nanotube layers was examined by immersion tests combined with SEM, XRD and FT-IR investigations. For reference, experiments were also carried out on compact anodic TiO(2) layers. The results clearly show that the presence of the nanotubes on a titanium surface enhances the apatite formation and that the 2-mum thick nanotube layer triggers deposition faster than the thinner layers. Tubes annealed to anatase, or a mixture of anatase and rutile are clearly more efficient in promoting apatite formation than the tubes in their "as-formed" amorphous state.

Journal ArticleDOI
TL;DR: Tina-COOH samples displayed a lower protein adsorption than all other groups, such as NH2-, -CH=CH2-terminated titanium thin films, and a tendency that the lower zeta-potential of the samples, the lower the protein Adsorption at their surfaces was observed.


Journal Article
TL;DR: In this paper, an atomic force microscopy (AFM) technique was used to image the transformation of titanium surface to TiO 2 surface on anodization and observed wide distribution of TiO2 particles ranging from submicron to nanometre sizes, fully covering the substrate forming a thin film on anodicizing.
Abstract: When titanium dioxide (TiO 2 ) is exposed to near-ultraviolet light, it exhibits strong bactericidal activity. Anatase phase of TiO 2 film was prepared by anodizing pure titanium coupons (substrate). Atomic force microscopy (AFM) technique was used to image the transformation of titanium surface to TiO 2 surface on anodization. We observed wide distribution of TiO 2 particles ranging from submicron to nanometre sizes, fully covering the substrate forming a thin film on anodizing. With the formation of a thin film of TiO 2 , we observed strong bactericidal activity. Bactericidal activity was attributed to the well-known photocatalytic property of the semiconductor TiO 2 . Here we present some arguments for reasoning out why certain semiconducting metal oxides exhibit photocatalytic properties and some do not. We also present some of the important elementary reaction steps considering adsorbed oxygen and water molecule as necessary molecules for the photooxidation process. Other reactions involved in producing reactive oxygen species and hydroxyl radical are presented to understand the process involved in photocatalytic biocidal activity. Finally, we present visualization of photocatalytic bactericidal activity of TiO 2 using AFM.

Journal ArticleDOI
TL;DR: In this article, a transparent nanotube array was grown from titanium thin films using an anodization technique, from which highly sensitive and selective hydrogen sensors that can operate at room temperature were fabricated.

Journal ArticleDOI
TL;DR: A dilute hydrochloric acid (HCl) treatment was developed for porous titanium, which removed sodium from the complexly shaped porous structure more effectively than conventional hot water treatment and had the highest osteoinductivity.

Journal ArticleDOI
TL;DR: In this paper, it was found that oxidation of TiH 2 particles is responsible for the observed shift in decomposition temperature since heating under argon did not produce this effect, and the shift can be tailored by choosing suitable pre-treatment parameters.

Book
24 Jan 2006
TL;DR: In this article, a failure investigation report of IMI 550 HPC-I (High Pressure COMPRESSOR (HPC-II) is reported. And the failure report is investigated.
Abstract: INTRODUCTION TO FRACTOGRAPHY Dimple Rupture Cleavage Fatigue Intergranular PHYSICAL METALLURGY OF TITANIUM ALLOYS Introduction Application of Titanium Alloys Effect of Alloying Elements Types of Titanium Alloys Alpha (alpha) Alloys Near alpha Alloys alpha + ss Alloys Metastable ss Alloys Beta Alloys Titanium Aluminides The Microstructure of Titanium Alloys Conventional Titanium Alloys Titanium Aluminides CHEMICAL COMPOSITIONS ALPHA ALLOYS NEAR-ALPHA ALLOYS ALPHA + BETA ALLOYS BETA ALLOYS TITANIUM ALUMINIDES Ti3Al-Based Alloys TiAl-Based Alloys CASE STUDY: FAILURE INVESTIGATION REPORT OF IMI 550 HIGH-PRESSURE COMPRESSOR (HPC-I) AERO ENGINE BLADE Introduction Investigation Chemical Analysis Microstructure Fractography Stress-Concentration Effects of a Notch Analysis of the Deposits Conclusion References Index

Journal ArticleDOI
TL;DR: The surface roughness (R(a)) was highly increased when titanium disks were immersed in artificial saliva containing F(-), H(2)O( 2) and lactic acid, and AFM appeared to be more sensitive than SEM in evaluating the corrosion of the titanium.

Patent
07 Apr 2006
TL;DR: In this paper, a multi-layer, multi-component high-k dielectric film with composition gradients is presented. But, the dielectrics are not formed with the same composition gradient as in this paper.
Abstract: The present invention provides systems and methods for forming a multi-layer, multi-component high-k dielectric film. In some embodiments, the present invention provides systems and methods for forming high-k dielectric films that comprise hafnium, titanium, oxygen, nitrogen, and other components. In a further aspect of the present invention, the dielectric films are formed having composition gradients.

Journal ArticleDOI
TL;DR: In this article, the R5 peptide derived from the NatSil protein in C. fusiformis can form titanium dioxide (TiO2) in a concentration dependent manner from the non-natural substrate, titanium bis(ammonium lactato)dihydroxide.
Abstract: Current approaches to the synthesis of metal oxides generally require harsh conditions. In contrast, many biological processes can produce intricate metal oxide nanostructures under ambient conditions. For example, the diatom Cylindrotheca fusiformis forms reproducible nanostructures from silicic acid using species specific peptides known as silaffins. Herein, we report that the R5 peptide a bioinspired analogue derived from the NatSil protein in C. fusiformis can form titanium dioxide (TiO2) in a concentration dependent manner from the non-natural substrate, titanium bis(ammonium lactato)dihydroxide. Additionally, the polypeptide poly(l-lysine) acts as a template for the biomimetic synthesis of TiO2. Subsequently, the nanoparticles were characterized using scanning electron microscopy, energy-dispersive X-ray spectrometry, and IR spectroscopy. A variable temperature X-ray diffraction study of the titanium dioxide phase transition from anatase to rutile was conducted. A delay in transition temperature was...

Journal ArticleDOI
TL;DR: It is indicated that etching with concentrated sulfuric acid is an effective way to modify the surface of titanium for biological applications.

Journal ArticleDOI
TL;DR: In this article, the structure of the aluminum and titanium octahedra was determined using the starting model and refining it against laboratory X-ray diffraction data, showing that water is lost reversibly below 423 K and that both structures are sta...
Abstract: A porous framework titanium(IV) N,N‘-piperazinebis(methylenephosphonate) (MIL-91(Ti)) and its aluminum analogue have been prepared under hydrothermal conditions (MIL = Material Institut Lavoisier). The structure of the aluminum analogue, AlOH(H2L)·nH2O (n ∼ 3, L = O3P−CH2−NC4H8N−CH2−PO3) was solved from a small single crystal and refined against laboratory powder X-ray diffraction data. The structure of the titanium form (TiO(H2L)·nH2O (n ∼ 4.5)) was determined using the structure of the aluminum form as a starting model and refining it against laboratory X-ray data. Their structures are built up from trans corner-sharing chains of TiO6 or AlO6 octahedra linked together in two directions via the diphosphonate groups. In each case this gives rise to a three-dimensional hybrid network with small channels along the b axis, filled with free water molecules. Thermogravimetric analysis and X-ray thermodiffractometry of the samples reveal that water is lost reversibly below 423 K and that both structures are sta...

Journal ArticleDOI
TL;DR: The analysis of the surface cation distribution indicates that Cu(II) has preference for octahedral sites, and when the copper content exceeds that for the stoichiometric CuCo2O4 spinel, a new CuO phase segregates at the surface.
Abstract: Cobalt oxide (Co3O4) and copper-doped cobalt oxide (CuxCo3-xO4) films have been prepared onto titanium support by the thermal decomposition method. The electrodes have been characterized by different techniques such as cyclic voltammetry, scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy (XPS). The effect on the electrochemical and crystallographic properties and surface morphology of the amount of copper in the oxide layer has been analyzed. The XPS spectra correspond to a characteristic monophasic Cu−Co spinel oxides when x is below 1. However, when the copper content exceeds that for the stoichiometric CuCo2O4 spinel, a new CuO phase segregates at the surface. The analysis of the surface cation distribution indicates that Cu(II) has preference for octahedral sites.

Journal ArticleDOI
TL;DR: In this article, an array of vertically aligned titanium oxide nanotubes was grown on the surface of titanium substrate by anodization, and a chemical treatment with NaOH solution to make them more bioactive with a formation of nanoscale sodium titanate structure.

Journal ArticleDOI
TL;DR: In this article, high-power impulse magnetron discharges have been implemented to achieve high ionization rates for surface modification because the flexibility of the thin film deposition process can be increased by ionizing the metallic vapor.

Journal ArticleDOI
TL;DR: This paper will present an overview of anodization techniques used to produce micro-porous titanium oxide structures and nano-tubular oxide structures, subsequent properties of these anodized titanium surfaces, and ultimately their in vitro as well as in vivo biological responses pertinent for orthopedic applications.
Abstract: Anodization is a well-established surface modification technique that produces protective oxide layers on valve metals such as titanium. Many studies have used anodization to produce micro-porous titanium oxide films on implant surfaces for orthopedic applications. An additional hydrothermal treatment has also been used in conjunction with anodization to deposit hydroxyapatite on titanium surfaces; this is in contrast to using traditional plasma spray deposition techniques. Recently, the ability to create nanometer surface structures (e.g., nano-tubular) via anodization of titanium implants in fluorine solutions have intrigued investigators to fabricate nano-scale surface features that mimic the natural bone environment. This paper will present an overview of anodization techniques used to produce micro-porous titanium oxide structures and nano-tubular oxide structures, subsequent properties of these anodized titanium surfaces, and ultimately their in vitro as well as in vivo biological responses pertinent for orthopedic applications. Lastly, this review will emphasize why anodized titanium structures that have nanometer surface features enhance bone forming cell functions.

Journal ArticleDOI
TL;DR: In this article, the microstructure, hardness and wear resistance of high-entropy Al0:5CoCrCuFeNiTix alloys are investigated using the well-developed arc-melting and casting method.
Abstract: High-entropy Al0:5CoCrCuFeNiTix alloys are synthesized using the well-developed arc-melting and casting method. The molar ratio (x )o f titanium is varied from 0 to 2.0. The microstructure, hardness and wear resistance of the alloys are investigated. The alloys exhibit simple FCC, BCC, CoCr-like and Ti2Ni-like phases. For a small addition of titanium, the alloys form a monolithic FCC solid-solution phase. Two phases of � 1 and � 2 based on BCC appear at the titanium content of x ¼ 0:4 and the � 1 phase becomes ordered at x ¼ 1:4. With the increase of titanium content, copper segregates to the interdendrite region in which nano-precipitates form. A CoCr-like phase forms when x ranges from 0.8 to 1.2. Ti2Ni-like phase forms when the titanium content exceeds x ¼ 1:0. The hardness value increases with titanium content. The alloys with lower titanium content exhibit similar wear resistance to Al0:5CoCrCuFeNi. The wear resistance is rapidly improved at titanium contents from 0.6 to 1.0, and reaches a maximum at x ¼ 1:0. This is followed by a gradual decrease with further increase of the titanium. The mechanisms behind the strengthening and wear resistance of the alloys are discussed. [doi:10.2320/matertrans.47.1395]

Journal ArticleDOI
TL;DR: In this paper, the authors describe the fabrication of multiscale porous nanocrystalline TiO2 monoliths through a one-step method that combines a sol−gel process and phase separation in template-free conditions.
Abstract: This article describes the fabrication of multiscale porous nanocrystalline TiO2 monoliths through a one-step method that combines a sol−gel process and phase separation in template-free conditions A large-dimension monolith with well-defined macropores and a mesostructured anatase-type TiO2 gel skeleton is spontaneously obtained by controlling the solution pH during the hydrolysis and polycondensation reactions of titanium alkoxides The size of the macropores is adjusted by the starting composition, and a crystallized anatase TiO2 skeleton is formed without heat treatment The use of titanium alkoxide strengthens the gel network by the formation of chemical bonding in the condensation reaction, which yields porous monoliths with higher mechanical strength than for the case of porous monoliths derived from colloidal TiO2 using freeze drying to maintain the porous morphology The average crystallite size of anatase TiO2 nanocrystals was found to be about 36 nm for the dried gel and about 50 nm for the