Topic
Tungsten
About: Tungsten is a research topic. Over the lifetime, 35225 publications have been published within this topic receiving 456213 citations. The topic is also known as: W & element 74.
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98 citations
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TL;DR: 2D h-W2 N3 demonstrates an excellent catalytic activity for cathodic HER with an onset potential of -30.8 mV as well as an overpotential of -98.2 mV for 10 mA cm-2 .
Abstract: 2D transition metal nitrides, especially nitrogen-rich tungsten nitrides (Wx Ny , y > x), such as W3 N4 and W2 N3 , have a great potential for the hydrogen evolution reaction (HER) since the catalytic activity is largely enhanced by the abundant WN bonding. However, the rational synthesis of 2D nitrogen-rich tungsten nitrides is challenging due to the large formation energy of WN bonding. Herein, ultrathin 2D hexagonal-W2 N3 (h-W2 N3 ) flakes are synthesized at atmospheric pressure via a salt-templated method. The formation energy of h-W2 N3 can be dramatically decreased owing to the strong interaction and domain matching epitaxy between KCl and h-W2 N3 . 2D h-W2 N3 demonstrates an excellent catalytic activity for cathodic HER with an onset potential of -30.8 mV as well as an overpotential of -98.2 mV for 10 mA cm-2 .
98 citations
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19 Aug 2015TL;DR: In this paper, a dep-etch-dep process integrating various deposition techniques with alternating pulses of surface modification and removal during etch is described for tungsten deposition in high aspect ratio features.
Abstract: Methods of depositing tungsten into high aspect ratio features using a dep-etch-dep process integrating various deposition techniques with alternating pulses of surface modification and removal during etch are provided herein.
98 citations
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TL;DR: In this paper, the surface modification was studied with scanning electron microscopy, and deuterium retention was measured by thermal desorption spectroscopy (TDS) in the case of high fluence exposures.
Abstract: Samples of tungsten and tungsten-tantalum alloy (with 5 mass per cent of Ta) were exposed to high-flux deuterium plasma at different fluences. The surface modification was studied with scanning electron microscopy, and deuterium retention was measured by thermal desorption spectroscopy (TDS). In the high fluence range of similar to 3.5 x 10(26)-10(27)m(-2), multiple large-size blisters are formed on the W surface, while blisters on the W-Ta surface are considerably smaller in size and number. Deuterium retention in this fluence range was found to be systematically higher in W than in W-Ta. Correlation between the evolution of the blistering patterns and the TDS spectra as a function of fluence suggests that trapping in the sub-surface cavities associated with blisters is the predominant trapping mechanism in tungsten in the case of high fluence exposures. We attribute the lower retention in W-Ta under the investigated conditions to the weaker blistering.
98 citations
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15 Mar 2003-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: The microstructural evolution and mechanical properties of a mechanically alloyed and two-stage sintered tungsten heavy alloy were investigated in this paper, where the micro-structural parameters such as particle size, matrix volume fraction, and tengsten/tungsten contiguity were controllable through the two stage sintering process.
Abstract: The microstructural evolution and mechanical properties of a mechanically alloyed and two-stage sintered tungsten heavy alloy were investigated Elemental powders of tungsten, nickel and iron of a composition corresponding to 93W–56Ni–14Fe were mechanically alloyed in a tumbler ball mill for 72 h Mechanically alloyed powders were solid-state sintered at 1300 °C for 1 hr in a hydrogen atmosphere followed by secondary sintering at 1445–1485 °C for a sintering time ranging from 4 to 90 min Solid-state sintered tungsten heavy alloys exhibited full densification (above 99% in relative density) due to the enhanced sintering resulting from mechanical alloying Secondary sintering with a rapid heating rate changed the microstructures of the solid-state sintered alloy with contiguous tungsten phases into a dispersion alloy with spherical tungsten particles embedded in the W–Ni–Fe matrix, maintaining fine tungsten particle due to the combination of a mechanical alloying and a short sintering time The two-stage sintered tungsten heavy alloy from mechanically alloyed powders showed finer tungsten particle (about 6 μm in diameter) than in conventional liquid-phase sintered tungsten heavy alloys The mechanical properties of a tungsten heavy alloy were found to be dependent on the microstructural parameters such as tungsten particle size, matrix volume fraction and tungsten/tungsten contiguity which are controllable through the two-stage sintering process
98 citations