China
Africa
Explore chapters and articles related to this topic
Vanadium and Chromium Groups
Published in Brian D. Fath, Sven E. Jørgensen, Megan Cole, Managing Global Resources and Universal Processes, 2020
Tungsten has the highest melting point of all metals (Table 2) and it has the highest tensile strength at temperatures higher than 1650°C, making it a valuable element in the alloy industry. Tungsten and its alloys are extensively used as filaments in lightbulbs, electron and television tubes, x-ray target, and heating elements for electrical furnaces. It has excellent corrosion resistance properties and it is attacked only slightly by mineral acids. Similar to tantalum, tungsten carbide has a high melting point at 2870°C and is an extremely hard material and hence is used in manufacturing cutting and drilling tools. Tungsten and its salts are widely applied in chemical and tanning industries and as high-temperature lubricants in the form of tungsten disulfide, which remains stable up to ~500°C.[14] Consequently, V, Mo, Cr, Ta, and W are regarded as essential commodities and metals of high strategic importance for years to come[15]
Tungsten Disulfide Polythiophene Nanocomposites
Published in Mahmood Aliofkhazraei, Advances in Nanostructured Composites, 2019
Nicole Arsenault, Rabin Bissessur, Douglas C. Dahn
Exfoliated tungsten disulfide was synthesized using the procedure from Matte et al. (2010), where thiourea (3.66 g, 48 mmol) and tungstic acid (0.25 g, 1.0 mmol) were weighed in a 48:1 molar ratio, respectively, mechanically mixed together and placed in a ceramic vessel. The vessel was placed in a ceramic tube inserted into a split furnace, under constant nitrogen atmosphere. The split furnace was slowly ramped up to 500°C over a period of 3 hours, and the temperature was held at 500°C for 3.5 hours. The reaction mixture was then cooled to room temperature for 12 hours under a nitrogen atmosphere. The resulting product was black in color.
Lubrication
Published in Keith L. Richards, Design Engineer's Sourcebook, 2017
Tungsten disulfide (WS2) is one of the most lubricous materials currently known to science. With a coefficient of friction at 0.03, it offers excellent dry lubricity unmatched by any other substance.
Effect of WS2 particles in cutting fluid on tribological behaviour of Ti–6Al–4V and on its machining performance
Published in Tribology - Materials, Surfaces & Interfaces, 2021
Sukanta Bhowmick, Behzad Eskandari, Girish Krishnamurthy, Ahmet T. Alpas
Hexagonal tungsten disulfide (WS2), a layered dichalcogenide compound with each lamellar unit consisting of a sheet of W atoms sandwiched between two hexagonally packed S layers bonded by S–W–S covalent bond, has been prevalently used for applications in vacuum or inert gas atmosphere due to its low COF. "Easy shear" of the WS2 layers that are bonded by van der Waals forces was generally reported in the literature as an interpretation of the low COF [36–38] under these atmospheres. Some authors reported that tribolayers that incorporated WS2 and WO3 were formed during the tribological test [39,40].