Showing papers on "Tungsten published in 2005"
259 citations
TL;DR: In this paper, the authors showed that by anodization of W in NaF electrolytes porous tungsten oxide layers can be formed under a range of experimental conditions, and that the morphology of the layers depends strongly on the NaF concentration as well as the formation potential.
240 citations
TL;DR: In this article, the effects of helium ion irradiation for tungsten and other metals have been extensively studied as functions of ion energy, temperature and fluence, for a wide range of burning plasma conditions, using not only ion accelerators, but also large-sized plasma confinement devices such as TRIAM-1M and LHD.
187 citations
TL;DR: In this article, the effect of bath chemistry, additives and operating conditions on the chemical composition, microstructure and properties of Ni-W alloys deposited from citrate-containing baths, in the absence of ammonia or ammonium salts, on stationary working electrodes was studied.
184 citations
TL;DR: In this article, strong photoluminescence (PL) was observed in nanostructured crystalline tungsten oxide thin films that were prepared by thermal evaporation, and two kinds of films were investigated, made of nanoparticles and another of nanowires.
Abstract: Strong photoluminescence (PL) is observed in nanostructured crystalline tungsten oxide thin films that are prepared by thermal evaporation. Two kinds of films are investigated—one made of nanoparticles and another of nanowires. At room temperature, strong PL emissions at ultraviolet-visible and blue regions are found in both of the films. Compared with the complete absence of emission of bulk phase tungsten oxide powder under the same excitation conditions, our results clearly demonstrate the quantum-confinement-effect-induced photoluminescence in nanostructured tungsten oxides.
151 citations
TL;DR: The results provide an indication that tungsten compounds may be introduced into the food chain and suggest the possibility of development of phytoremediation-based technologies for the cleanup of tsungsten contaminated sites.
148 citations
TL;DR: The design of a tungsten thermal source with extraordinarily high directivity in the near infrared, comparable to the directivity of a CO2 laser is reported.
Abstract: We report the design of a tungsten thermal source with extraordinarily high directivity in the near infrared, comparable to the directivity of a CO2 laser. This high directivity is the signature of the long-range correlation of the electromagnetic field in the source plane. This phenomenon is due to the resonant thermal excitation of surface-plasmon polaritons.
143 citations
TL;DR: In this article, a modified thermal evaporation technique was used to obtain films of nanostructured WO3 with high surface roughness for gas-sensing applications.
127 citations
TL;DR: In this article, the deuterium ion irradiation on tungsten has been carried out with incident energies of 100 eV and flux of 1.5 eV at a temperature in range between 333-K and 1130-K up to a dose of 1Õ×1026-D+m−m−2.
122 citations
117 citations
TL;DR: In this paper, the authors demonstrated shear localization in bulk tungsten (W) of commercial purity under dynamic uniaxial compression and showed that ultrafine microstructure achieved in bcc materials leads to elevated strength and ductility, as well as reduced strain hardening and strain rate hardening.
Abstract: Shear localization is demonstrated in bulk tungsten (W) of commercial purity under dynamic uniaxial compression. Microstructure refinement via severe plastic deformation was the strategy used to induce this unusual deformation mode for W. The ultrafine microstructure achieved in bcc materials leads to elevated strength and ductility, as well as reduced strain hardening and strain rate hardening, thus enhancing the propensity for adiabatic plastic flow localization.
TL;DR: In this article, the crystal structure of the solid solutions La2Mo2-yWyO9 (y ≤ 0.5) and La1La3Mo(y ≤ 1.4) has been studied using X-ray and neutron powder diffraction.
Abstract: The crystal structure of the solid solutions La2Mo2-yCryO9 (y ≤ 0.5) and La2Mo2-yWyO9 (y ≤ 1.4) has been studied using X-ray and neutron powder diffraction. These two series of lanthanum molybdates, which belong to the LAMOX family of fast oxide-ion conductors, exhibit a different structural behavior depending on the substituting element. The Cr series follows a regular Vegard-type evolution of crystallographic parameters. However, the behavior of the W series is different, the lattice constant varying in a nonlinear fashion with substitution level, resulting in a smaller cell volume for higher tungsten contents, despite the larger ionic radius of tungsten. Two main structural effects are evidenced: a variation in the distribution of ligands around tungsten, made apparent through the changing balance of oxygen O2 and O3 site occupancies along the series, and a nonlinear evolution of interatomic distances and angles involving the O1 oxygen site. An alternative structural description, based on [O1La3Mo] an...
TL;DR: In this article, the authors describe the response of plasma facing components manufactured with tungsten and CFC to energy loads characteristic of Type I ELMs and disruptions in ITER, in experiments conducted under an EU/RF collaboration in two plasma guns (QSPA and MK-200UG) at the TRINITI institute.
TL;DR: In this paper, the impact test results on the use of dispersion strengthened tungsten for divertor structures are discussed in detail, and the impact of these results on use of tengsten as structural material for fusion-specific neutron irradiation is discussed.
TL;DR: Ethylenediamine-tungsten oxide clearly displays a lack of terminal -NH3(+) ammonium groups which appear in hybrids with longer organic molecules, thus indicating that the longer chains are bound by electrostatic interactions as well as or in place of the hydrogen bonding that must be present in the shorter chain ethylenedienine hybrids.
Abstract: Tungsten oxide-organic layered hybrid materials have been studied by infrared and Raman spectroscopy and demonstrate a difference in bonding nature as the length of the interlayer organic "spacer" molecule is increased. Ethylenediamine-tungsten oxide clearly displays a lack of terminal -NH3(+) ammonium groups which appear in hybrids with longer organic molecules, thus indicating that the longer chains are bound by electrostatic interactions as well as or in place of the hydrogen bonding that must be present in the shorter chain ethylenediamine hybrids. The presence of organic molecules between the tungsten oxide layers, compared with the layered tungstic acid H2WO4, shows a decrease in the apical W=O bond strength, as might be expected from the aforementioned electrostatic interaction.
TL;DR: In this paper, melted tungsten carbide powders on the surface of AISI 4340 steel was applied by using TIG method and it was observed that it has been solidified in different microstructures depending on the production parameters.
Patent•
28 Sep 2005
TL;DR: In this paper, the use of selective oxidization to oxidize silicon in the presence of tungsten and/or Tungsten nitride in memory cells and memory arrays is discussed.
Abstract: The present invention relates to use of selective oxidation to oxidize silicon in the presence of tungsten and/or tungsten nitride in memory cells and memory arrays. This technique is especially useful in monolithic three dimensional memory arrays. In one aspect of the invention, the silicon of a diode-antifuse memory cell is selectively oxidized to repair etch damage and reduce leakage, while exposed tungsten of adjacent conductors and tungsten nitride of a barrier layer are not oxidized. In some embodiments, selective oxidation may be useful for gap fill. In another aspect of the invention, TFT arrays made up of charge storage memory cells comprising a polysilicon/tungsten nitride/tungsten gate can be subjected to selective oxidation to passivate the gate polysilicon and reduce leakage.
TL;DR: Tungsten carbide nanocrystal modified Pt catalysts have been prepared by an intermittent microwave heating method and show an improved activity for oxygen electroreduction in alkaline media.
01 Apr 2005
TL;DR: In this paper, X-ray absorption spectroscopy (XANES) at the tungsten LI and LIII absorption edges was used to identify the presence of W −O− and WO terminal bonds and a progressive apparition of W−O−W bridging bonds for the most WO3 concentrated samples (⩾30% molar).
TL;DR: In this article, a study of helium retention and surface blistering with regard to helium dose, temperature, pulsed implantation, and tungsten microstructure was conducted to better understand what may occur at the first wall of an inertial fusion energy reactor.
TL;DR: In this paper, a core-shell structured WO3/TiO2 spheroids were synthesized through a conventional incipient wetness impregnation method and systematically characterized by X-ray diffraction, N2 sorption, scanning electron microscopy, transmission electron microscope, laser Raman spectroscopy, thermogravimetric and differential thermal analysis.
TL;DR: In this paper, the authors used in situ quartz crystal microbalance (QCM) measurements as a function of the reactant exposure and deposition temperature to explore the atomic layer deposition (ALD) of tungsten.
TL;DR: Tungsten-containing hexagonal mesoporous silica (HMS) has been synthesized by using dodecylamine as template at room temperature as discussed by the authors, and it is very active as a catalyst for the selective oxidation of cyclopentene (CPE) to glutaraldehyde (GA) with environmentally benign hydrogen peroxide as the oxidant.
Abstract: Tungsten-containing hexagonal mesoporous silica (HMS) has been synthesized by using dodecylamine as template at room temperature. The as-prepared novel material is very active as a catalyst for the selective oxidation of cyclopentene (CPE) to glutaraldehyde (GA) with environmentally benign hydrogen peroxide as the oxidant. Tungsten species could stably exist in the silica-based matrix of HMS up to a Si/W molar ratio of 30, as determined by X-ray diffraction (XRD), laser Raman spectroscopy, and FT-IR. Proper content of tungsten species and its high dispersion account for its high activity. Complete conversion of cyclopentene and very high yield of glutaraldehyde (∼76.3%) are obtained over the W-HMS catalyst with a Si/W molar ratio at 30. Furthermore, almost no tungsten species are leached into the reaction solution, enabling the catalyst to be employed for many reaction cycles without dramatic deactivation.
TL;DR: In this article, high temperature helium and deuterium implantation on tungsten powder metallurgy samples was studied using the University of Wisconsin inertial electrostatic confinement device.
01 Nov 2005
TL;DR: In this paper, mixed tungsten/steel interlayers were applied to reduce the residual and thermal stresses at the substrate-coating interface and to improve the adhesion of the coating.
Abstract: Vacuum plasma-spraying (VPS) can be used for the industrial deposition of thick W coatings on actively water-cooled components made of low activation steel or stainless steel. Mock-ups made of martensitic steels, EUROFER and F82H, as well as steel 316L, were coated with 2 mm thick W-VPS layers. The coated materials are candidates for first wall components (ITER and DEMO) receiving moderate heat load of up to 1 MW/m2. Mixed tungsten/steel interlayers were applied to reduce the residual and thermal stresses at the substrate–coating interface and to improve the adhesion of the coating. The advantage of this mixed interlayer is that no further (high activation) materials have to be introduced to improve coating adhesion. The characterisation of the W-VPS layers includes the evaluation of the coating microstructure, the measurement of physical and mechanical properties and the metallographical examination before and after heat load tests. Heat load tests with steady state operation up to 2.5 MW/m2 and cycling heat loads of 2 MW/m2, were successfully completed. They confirm the thermomechanical suitability of industrially manufactured W-VPS coatings for plasma facing first wall components made of steel.
Patent•
19 Apr 2005
TL;DR: In this article, a method of making titanium-tungsten alloys and composites using powders of tungsten less then 3 μm in size, such as 1 μm or less, is presented.
Abstract: Disclosed herein are titanium-tungsten alloys and composites wherein the tungsten comprises 0.5% to 40% by weight of the alloy. Also disclosed is a method of making such alloys and composites using powders of tungsten less then 3 μm in size, such as 1 μm or less. Also disclosed is a method of making the titanium alloy by powder metallurgy, and products made from such alloys or billets that may be cast, forged, or extruded. These methods of production can be used to make titanium alloys comprising other slow-diffusing beta stabilizers, such as but not limited to V, Nb, Mo, and Ta.
TL;DR: In this paper, electron beam welds of aluminum alloy 2219 have been made and their mechanical properties were evaluated by tensile testing and pitting corrosion resistance by potentio dynamic polarization tests.