Results 241 to 250 of about 175,593 (294)

Tungsten toxicity

Chemico-Biological Interactions, 2012
There is emerging evidence that tungsten has toxic health effects. We summarize the recent tungsten toxicity research in this short review. Tungsten is widely used in many commercial and military applications because it has the second highest melting temperature of any element.
Mark L, Witten, Paul R, Sheppard, Brandon L, Witten   +2 more
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Tungsten and Tungsten Alloy Products

1999
Besides tungsten metal, only those alloys which were described in Chapter 6 are treated in this chapter. Alloys produced by melting metallurgy as well as the cemented carbides hardmetals) and their application are treated in Chapters 8 and 9, respectively.
Erik Lassner, Wolf-Dieter Schubert
openaire   +1 more source

Electrochemical preparation of tungsten, tungsten carbide and cemented tungsten carbide

Mineral Processing and Extractive Metallurgy, 2013
Tungsten is conventionally made by the reduction of tungsten oxide with hydrogen, tungsten carbide by the reaction of tungsten with carbon and cemented tungsten carbide by the sintering together of tungsten carbide with a metal, usually cobalt. This paper reports the electrochemical preparation of tungsten, tungsten carbide and cemented tungsten ...
D.-H. Tran-Nguyen, D. Jewell, D. J. Fray
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Tungsten(VI) and Tungsten(V) Fluoride Complexes

Chemistry – A European Journal, 2009
AbstractWF6 reacts with phosphines R3P forming 1:1 compounds. With R=P(CH3)3 the coordination around the tungsten atom is capped trigonal prismatic, with R=P(CH3)2C6H5 the coordination is capped octahedral, as established by single‐crystal structure determinations: [(CH3)3PWF6]: a=752.5(21), b=945.7(24), c=629.8(18) pm.
Said, El-Kurdi, Abdal-Azim, Al-Terkawi, Bernd M, Schmidt, Anton, Dimitrov, Konrad, Seppelt   +4 more
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Fabrication of Tungsten and Tungsten-25%-Rhenium Tubing

Nuclear Applications, 1965
Techniques were developed for the fabrication of seamless tungsten and tungsten-25%rhenium tubing. Appropriate procedures were established for primary extrusion, re-extrusion, and warm drawing.
S. ISSEROW, J. G. HUNT, R. G. JENKINS, G. I. FRIEDMAN   +3 more
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Conversion of tungsten nitride to pure tungsten

Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 1998
The properties of W2N thin films deposited on Si, SiO2, and Ta2O5 by plasma-enhanced chemical vapor deposition, with and without an electron cyclotron resonance plasma formed SiO2 (ECR-SiO2) top layer are comparatively investigated. The ECR-SiO2 top layer can effectively promote the conversion of W2N to pure W while samples are annealed at high ...
Jun Lin, Atsuhiro Tsukune, Toshiya Suzuki, Masao Yamada   +3 more
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Mobility of tungsten clusters on tungsten surfaces

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2019
Abstract We report on an accelerated molecular dynamics investigation of surface transport mechanisms on W surfaces. These mechanisms likely influence the formation of nano-fuzz in fusion plasma-facing conditions. The simulations use an embedded-atom potential to investigate the diffusion mechanisms of W clusters (Wn, n = 2–9) on W(1 1 0) and W(1 0 0)
L. Yang, B.D. Wirth, Danny Perez, Arthur F. Voter   +3 more
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Measurements of the Polarizability of Tungsten Adatoms on Tungsten (110) Planes

Physica Status Solidi (a), 1972
It is shown that high quality room temperature field ion images can be obtained. Image contrast can be enhanced by using a Ne-Ar mixture. The enhancement is due to field adsorption of argon at room temperature. Using the room temperature FIM, one can observe the movements of individual adatoms on surface planes.
T. T. Tsong, R. J. Walko
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Reduction of tungsten oxide to tungsten metal

Metallurgical Transactions B, 1976
Tungsten oxide, WO2.96, was reduced toα-W in hydrogen for various time periods over the temperature range 500°C to 900°C. Intermediate oxides were determined using X-ray diffraction analysis of the semireduced powders. Several dopant conditions were used, to find the effect on oxide structures and reaction kinetics of the usual dopants K, Si and Al ...
Theodore R. Wilken, William R. Morcom, Charles A. Wert, John B. Woodhouse   +3 more
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Diffusion of tungsten on stepped tungsten surfaces

Surface Science, 1990
Abstract Self-diffusion of thermally generated tungsten atoms near (123) and (257), on the zone (011)–(112) and on (023), on the zone (011)–(001) of a tungsten field emitter has been investigated by the field-emission fluctuation method, using a rectangular probe in order to investigate diffusion anisotropy. In agreement with earlier findings of Gong
D.S. Choi, S.K. Kim, R. Gomer
openaire   +1 more source