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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 article, the constituent diffusion at the contact interface between tool material and Ti-6Al-4V alloy at high-temperature environment, the crater wear on the rake surface of the tool, and the chips collected from high-speed milling with straight tungsten carbide tools were analyzed by the scanning electron microscope with energy dispersive X-ray spectroscopy.
Abstract: During high-speed machining Ti-6Al-4V alloy, high-temperature at the tool–chip interface and the concentration gradient of chemical species between tool material and workpiece material support the activation of diffusion process, and therefore the crater wear forms on the rake surface of the cutting tool at a short distance from the cutting edge. In this paper, the diffusion analysis was theoretically proposed. The constituent diffusion at the contact interface between tool material and Ti-6Al-4V alloy at high-temperature environment, the crater wear on the rake surface of the tool, and the chips collected from high-speed milling Ti-6Al-4V alloy with straight tungsten carbide tools were analyzed by the scanning electron microscope with energy dispersive X-ray spectroscopy. The constituents inside the tool could diffuse into the workpiece and the diffusion layer was very thin and close to the interface. Compared with the diffusion of tungsten and carbon atoms, the pulling out and removing of the tungsten carbide (WC) particles due to cobalt diffusion dominated the crater wear mechanism on the rake surface of the cutting tool.

105 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used the reactive d.c.-magnetron sputter technique in conventional and unbalanced modes to prepare tungsten-containing hydrodcarbon (W-C:H) coatings which have low friction coefficients and high wear resistances.
Abstract: The reactive d.c.-magnetron sputter technique in conventional and unbalanced modes was used to prepare tungsten-containing hydrodcarbon (W-C:H) coatings which have low friction coefficients and high wear resistances. Reproducible deposition processes stable over a long time without poisoning could be realized using a plasma emission monitor (PEM) control unit. From investgigation of light emission spectra of the magnetron discharge the intensive tungsten line at 401 nm was selected as most suitable for process control. The dependences of characteristic process parameters such as target voltage, optical emission intensity or deposition rate on the reactive gas flow were quite different from those known for the reactive sputter deposition of TiN or other nitrides and oxides. For both tungsten and WC targets the PEM intensity decreased monotonically with increasing acetylene flow. However, the deposition rates on substrates with floating potential increased. An additional r.f. excitation of the substrate electrode caused only slight changes in rate and metal content in the coatings. It can be concluded that the sputter process is dominant for W-C:H growth. The contribution of direct plasma polymetrization at the substrate is small. From-X-ray diffraction investigations it was concluded that the W-C:H coatings contain microcrystallites of the metastable cubic tungsten carbide WC1 − x. The Vickers hardness and Young's modulus depend on the atomic ratio of tungsten to carbon.

104 citations

Journal ArticleDOI
TL;DR: In this paper, graphitic carbon nitride (g-C3N4) was prepared by heating melamine and then its specific surface area was enlarged by hydrothermal treatment in aqueous sodium hydroxide solution.
Abstract: Graphitic carbon nitride (g-C3N4) was prepared by heating melamine and then its specific surface area was enlarged by hydrothermal treatment in aqueous sodium hydroxide solution. The g-C3N4 samples were blended with tungsten(VI) oxide (WO3) using a planetary mill in order to improve photocatalytic activity. The composite photocatalyst with optimized amounts of these contents showed higher photocatalytic activity for decomposition of acetaldehyde under visible-light irradiation than did original samples. From the results, we concluded that the composite photocatalyst utilizes both high oxidation ability of WO3 and high reduction ability of g-C3N4 by Z-scheme charge transfer.

104 citations

Journal ArticleDOI
Owais Ahmed Waseem1, Ho Jin Ryu1
TL;DR: This study explored the potential of powder metallurgy processing for the fabrication of a high-entropy alloy and other derived compositions with enhanced hardness and strength through sintering of reduced-activation alloys for fusion plasma-facing materials.
Abstract: The WxTaTiVCr high-entropy alloy with 32at.% of tungsten (W) and its derivative alloys with 42 to 90at.% of W with in-situ TiC were prepared via the mixing of elemental W, Ta, Ti, V and Cr powders followed by spark plasma sintering for the development of reduced-activation alloys for fusion plasma-facing materials. Characterization of the sintered samples revealed a BCC lattice and a multi-phase structure. The selected-area diffraction patterns confirmed the formation of TiC in the high-entropy alloy and its derivative alloys. It revealed the development of C15 (cubic) Laves phases as well in alloys with 71 to 90at.% W. A mechanical examination of the samples revealed a more than twofold improvement in the hardness and strength due to solid-solution strengthening and dispersion strengthening. This study explored the potential of powder metallurgy processing for the fabrication of a high-entropy alloy and other derived compositions with enhanced hardness and strength.

104 citations

Journal ArticleDOI
TL;DR: In this article, uniform single-crystalline ultrathin W18O49 nanowires with diameters less than 2'nm and aspect ratios larger than 100 have been synthesized, and, despite their flexibility, assembled into thin films with high orientational order over a macroscopic area by the Langmuir-Blodgett technique.
Abstract: Alignment of nanowires over a large area of flat and patterned substrates is a prerequisite to use their collective properties in devices such as gas sensors. In this work, uniform single-crystalline ultrathin W18O49 nanowires with diameters less than 2 nm and aspect ratios larger than 100 have been synthesized, and, despite their flexibility, assembled into thin films with high orientational order over a macroscopic area by the Langmuir–Blodgett technique. Alignment of the tungsten oxide nanowires was also possible on top of sensor substrates equipped with electrodes. Such sensor devices were found to exhibit outstanding sensitivity to H2 at room temperature.

104 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,055
20222,162
2021902
20201,216
20191,447
20181,372