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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TL;DR: In this paper, the influence of the dispersion technique on the sintering behavior of W-Cu composites is investigated, and a powder consisting of composite particles has an optimal Cu dispersion and a very fine tungsten phase.
122 citations
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TL;DR: In this paper, the authors summarized the core and divertor radiative characteristics of potential seeding species, namely noble gases and nitrogen, and showed that nitrogen is a suitable replacement for carbon as a divertor radiator.
121 citations
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15 Mar 2013TL;DR: In this paper, a remote plasma etch formed from a fluorine-containing precursor and/or hydrogen (H2) is described, where the plasma effluents react with exposed surfaces and selectively remove tungsten while very slowly removing other exposed materials.
Abstract: Methods of selectively etching tungsten relative to silicon-containing films (e.g. silicon oxide, silicon carbon nitride and (poly)silicon) as well as tungsten oxide are described. The methods include a remote plasma etch formed from a fluorine-containing precursor and/or hydrogen (H2). Plasma effluents from the remote plasma are flowed into a substrate processing region where the plasma effluents react with the tungsten. The plasma effluents react with exposed surfaces and selectively remove tungsten while very slowly removing other exposed materials. Sequential and simultaneous methods are included to remove thin tungsten oxide which may, for example, result from exposure to the atmosphere.
121 citations
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TL;DR: In this article, the partitioning of molybdenum and tungsten between ilmenite (ilm) and silicic melts has been determined at 800 degrees C, 1 kbar of pressure, and at two oxygen fugacities.
Abstract: The partitioning of molybdenum and tungsten between ilmenite (ilm) and silicic melts has been determined at 800 degrees C, 1 kbar of pressure, and at two oxygen fugacities. At the oxygen fugacity of the graphite-methane(-water) buffer, D (super ilm/melt) Mo = 0.42, and D (super ilm/melt) W = 0.39. Near the nickel-nickel oxide buffer, D (super ilm/melt) Mo = 0.22 and D (super ilm/melt) W = 0.5. The variations in the partition coefficients with f (sub o 2 ) are significant at the 0.06 and 0.33 levels for molybdenum and tungsten, respectively. The observed variation with oxygen fugacity is tentatively extrapolated to more complex systems and implies that the oxygen fugacity which prevails during magmatic crystallization may play a role in determining the Mo/W ratio in porphyry, skarn, or other hydrothermal mineral deposits. Examination of the literature on molybdenum- and tungsten-bearing mineral deposits indicates that systems with high W/Mo ratios are rather reduced and exhibit high CH 4 /CO 2 ratios in fluid inclusions, low Fe (super +3) /Fe (super +2) ratios in iron-bearing minerals, and low oxygen fugacities in associated igneous rocks. On the other hand, deposits with high Mo/W ratios are associated with rather oxidized magmatic systems. We suggest that f (sub o 2 ) -dependent sequestration of molybdenum and tungsten in ferromagnesian phases during plutonic consolidation exerts a control on the relative efficiencies of removal of these metals from magmas into ore-forming fluids.
121 citations
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TL;DR: In this paper, surface and sub-surface morphology and deuterium retention in polycrystalline tungsten, undamaged and pre-damaged with 5.5 MeV W2+ ions to damage levels of 0.04, 0.4, and 1.2
121 citations