Chemical vapor synthesis (CVS) of tungsten nanopowder in a thermal plasma reactor

Ryu, Taegong; Sohn, Hong Yong; Hwang, Kyu Sup; Fang, Zhigang Zak

doi:10.1016/j.ijrmhm.2008.06.002

Cited by 75 publications

(30 citation statements)

References 23 publications

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“…We postulate that the particle sizes in these studies are large compared to the crystallite size. Ryu et al, [13] on the other, obtained nanopowders that were fairly well dispersed, although there is definitely still some agglomeration, resulting in particle sizes greater than 100 nm, as approximated from TEM analysis.…”

Section: Resultsmentioning

confidence: 95%

“…These include self-propagating high-temperature synthesis, [8] reverse micelle synthesis, [9] thermal methods, [10][11][12][13] mechanical milling, [14] and electrochemical techniques. [15] Most of the resulting powders from these processes are very likely heavily agglomerated, although a determination of the levels of agglomeration have not been reported in most cases.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Particle and Crystallite Size in Tungsten Nanopowder Synthesis

Graeve

Madadi

Kanakala

et al. 2010

Metall Mater Trans A

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Tungsten nanopowders were synthesized by a low-temperature technique and then heat treated in a gaseous reductive atmosphere in order to study the phase evolution, crystallite size, and particle size of the powders as the heat treatment temperature was modified. Synthesis of the powders was carried out in aqueous media using NaBH 4 as a reducing agent using careful control of the pH of the solutions. The XRD patterns of the as-synthesized powders showed an amorphous phase. After washing, energy dispersive spectroscopy showed that the powders had peaks for oxygen and tungsten. In order to promote crystallization and eliminate the oxygen, the powders were heat treated at 773 K, 923 K, and 1073 K (500°C, 650°C, and 800°C) in a H 2 /CH 4 reducing atmosphere for 2 hours. XRD after heat treatment showed a-W peaks for the powders treated at 1073 K and 923 K (800°C and 650°C) and a mixture of b-W and a-W for the powders treated at 773 K (500°C). The crystallite sizes determined from X-ray peak broadening were 12, 16, and 20 nm, whereas the average particle sizes from dynamic light scattering were 260, 450, and 750 nm, for heat treatment temperatures of 773 K, 923 K, and 1073 K (500°C, 650°C, and 800°C), respectively. The average crystallite size and particle sizes increased proportionally with the treatment temperature, in contrast to what has been found for some ceramics, in which as the heat treatment temperature is increased, the crystallite size increases, but the particle size stays constant.

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Section: Resultsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Analysis of Particle and Crystallite Size in Tungsten Nanopowder Synthesis

Graeve

Madadi

Kanakala

et al. 2010

Metall Mater Trans A

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“…To date, such as high-energy ball milling [7], molten salt electrolysis [8], selfpropagating high-temperature synthesis (SHS) [9][10][11], chemical vapor synthesis [12] and chemical reduction [13] method are used in the production of nanoscale tungsten powders. Unfortunately, these techniques for fabricating of tungsten nanoparticles all suffer from various disadvantages, including use of expensive raw material precursors, requirement of multi-steps high temperature process and difficulty in establishing a commercial application.…”

Section: Introductionmentioning

confidence: 99%

Refining mechanisms of arsenic in the hydrogen reduction process of tungsten oxide

Zhu

Tan

et al. 2015

Advanced Powder Technology

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“…Over recent years, there has been a number of processes described in the literature for production of nanopowders using arc-based technologies [1][2][3][4][5][6][7][8][9][10][11]. These technologies include plasma jet systems where precursor materials are injected into the plasma stream [2], and various configurations of plasma jets and transferred arcs, [3][4][5][6][7][8][9] including hypersonic plasma production and deposition [10].…”

Section: Introductionmentioning

confidence: 99%

“…These technologies include plasma jet systems where precursor materials are injected into the plasma stream [2], and various configurations of plasma jets and transferred arcs, [3][4][5][6][7][8][9] including hypersonic plasma production and deposition [10]. Non-plasma systems such as explosive wire [11] and milling have also been used.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Al Nanopowders in an Anodic Arc

Haidar

2009

Plasma Chem Plasma Process

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Nanopowders of metals and metal oxides have been produced using an arc operated between a refractory rod anode and a hollow cathode (J. Haidar in A method and apparatus for production of material vapour, Australian Patent No. 756273, 1999). the arc attachment to the anode is through a small region of molten metal located at the tip of the rod anode. Heat from the arc evaporates the molten metal and the vapour is passed through the arc plasma before condensing into sub-micron particles downstream of the cathode. A precursor metal is continuously fed onto the tip of the anode to maintain the molten metal region and compensate for losses of materials due to evaporation. The particle size of the produced powder depends on the pressure in the arc chamber and for production of nanoparticles in the range below 100 nm we use a pressure of 100 torr. Aluminium has been used as a precursor material, leading to production of aluminium metal nanopowders when the arc is operated in argon and to aluminium oxide nanopowders for operation in air. For operation in air, the products are made of c-Al 2 O 3 .

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Chemical vapor synthesis (CVS) of tungsten nanopowder in a thermal plasma reactor

Cited by 75 publications

References 23 publications

Analysis of Particle and Crystallite Size in Tungsten Nanopowder Synthesis

Analysis of Particle and Crystallite Size in Tungsten Nanopowder Synthesis

Refining mechanisms of arsenic in the hydrogen reduction process of tungsten oxide

Synthesis of Al Nanopowders in an Anodic Arc

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