scispace - formally typeset
Search or ask a question
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.


Papers
More filters
Journal ArticleDOI
TL;DR: Field electron emission investigations on pulsed laser-deposited molybdenum disulfide (MoS2) thin films on W-tip and Si substrates hold great promise for the development of PLD MoS2 films in application domains such as field emitters and heterostructures for novel nanoelectronic devices.
Abstract: We report field electron emission investigations on pulsed laser-deposited molybdenum disulfide (MoS2) thin films on W-tip and Si substrates. In both cases, under the chosen growth conditions, the dry process of pulsed laser deposition (PLD) is seen to render a dense nanostructured morphology of MoS2, which is important for local electric field enhancement in field emission application. In the case of the MoS2 film on silicon (Si), the turn-on field required to draw an emission current density of 10 μA/cm2 is found to be 2.8 V/μm. Interestingly, the MoS2 film on a tungsten (W) tip emitter delivers a large emission current density of ∼30 mA/cm2 at a relatively lower applied voltage of ∼3.8 kV. Thus, the PLD-MoS2 can be utilized for various field emission-based applications. We also report our results of photodiode-like behavior in (n- and p- type) Si/PLD-MoS2 heterostructures. Finally we show that MoS2 films deposited on flexible kapton substrate show a good photoresponse and recovery. Our investigations t...

171 citations

Journal ArticleDOI
TL;DR: In this article, the hydrogenation of cyclohexene and benzene on nickel-tungsten sulfide and tungsten disulfide catalysts is compared. And the role of nickel in multiplying the number of active tungststen sites is evaluated.

170 citations

Journal ArticleDOI
TL;DR: In this paper, a critical review of the methods that have been reported in the literature for improving the ductility of tungsten in order to understand the critical factors that control the ductile (or lack thereof) in Tungsten.
Abstract: Pure tungsten and tungsten alloys with minor alloying additions are known to be brittle at room temperature and have high ductile-to-brittle transition temperatures (DBTT). Improving the ductility of tungsten can have significant impact on both the manufacturing of and the range of applications of tungsten. Although there has been a significant volume of reported research on improving the ductility of tungsten over the span of several decades, it remains a difficult challenge. This is at least partially attributable to the fact that the understanding on the mechanical properties of tungsten and their dependence on microstructure has been insufficient. This article attempts to offer a critical review of the methods that have been reported in the literature for improving the ductility of tungsten in order to understand the critical factors that control the ductility (or lack thereof) in tungsten. It is clear from the literature that all tungsten materials that have been reported to be ductile at room temperature, or to have drastically reduced DBTT, are the result of thermomechanically processed (TMP) material with deformed and textured microstructures. Alloying tungsten with rhenium is essentially the only known method to improve the ductility of tungsten by alloying (excluding the class of alloys known as heavy alloys which are composites of tungsten with nickel and iron). Although there have been a large number of research reports in recent years on the effect of additives, including oxides, carbides, and others, the results are inconclusive to date or insignificant with respect to the effects of those additives on the ductility of tungsten independent of the effects of thermomechanical working. Using ultrafine-grained or nanocrystalline microstructure to improve the ductility of tungsten is another approach that has appeared promising. However, the results to date have not shown that the ductility of tungsten can be improved by reducing the grain size alone, without the benefits of thermomechanical processed or deformed microstructures. Another objective of this review is to examine the correlation between the ductility of tungsten and different microstructures resulting from different processing methods and compositions.

170 citations

Journal ArticleDOI
TL;DR: In this article, hierarchical WO 3 -TiO 2 nanotubes (WTNs) composite structures were obtained by anodization of titanium in a single-step process using sodium tungstate as the tungsten source.

170 citations

Journal ArticleDOI
TL;DR: Takamura et al. as mentioned in this paper investigated the effects of a transient heat load on tungsten damaged by helium plasma irradiation using a ruby laser with long pulse duration in the divertor simulator NAGDIS-II.
Abstract: The effects of a transient heat load on tungsten damaged by helium plasma irradiation have been investigated using a ruby laser with long pulse duration in the divertor simulator NAGDIS-II (Takamura et al 2002 Plasma Sources Sci. Technol. 11 A42). The pulse width of the ruby laser was ∼0.6 ms, which is close to that of the expected heat load accompanied by type-I edge localized modes (ELMs) in ITER operation. Helium holes/bubbles, which were formed in the surface region of powder metallurgy tungsten due to the exposure to the helium plasma, disappeared after the laser pulse irradiation to the tungsten surface with sufficient pulse energy. The results indicated that the transient heat loads similar to those expected by ELMs will mitigate damages such as bubbles and holes produced by helium irradiation. When a vacuum plasma sprayed tungsten coating on graphite was exposed to the helium plasma, the surface was covered with arborescent nanostructured tungsten containing many helium bubbles inside the structure. Melting traces were found on the surface after the laser pulses irradiated the surface even though the pulse energy was lower than that for melting bulk tungsten. A numerical temperature calculation of the sample suggested that the effective thermal conductivity near the surface dramatically decreased by several orders of magnitude due to the formation of nanostructured tungsten.

170 citations


Network Information
Related Topics (5)
Oxide
213.4K papers, 3.6M citations
90% related
Hydrogen
132.2K papers, 2.5M citations
88% related
Silicon
196K papers, 3M citations
87% related
Carbon
129.8K papers, 2.7M citations
86% related
Raman spectroscopy
122.6K papers, 2.8M citations
85% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,055
20222,162
2021902
20201,216
20191,447
20181,372