Hydrogen plasma jet

Hydrogen reduction of chlorides in thermal plasma can be apphed not only to produce powder of individual metals but also to produce different intermetalhc compounds. The composition of the generated crystals copies the composition of the chloride mixture in the gas phase. This effect permits the production of the intermetallic compounds with the required composition. Refractory intermetallic compounds based on niobium and vanadium were synthesized from their chlorides (conversion close to 100%) in a hydrogen plasma jet generated by RF-ICP discharge (Bashkirov Medvedev, 1968). The reaction products were crystallized on a substrate sustained at a temperature of about 1000°C. The plasma-metallurgical technology is proven to be effective in the synthesis of vanadium-Hsilicon... 

Heating of Coal Particles and Acetylene Quenching During Pyrolysis of Coal in Argon and Hydrogen Plasma Jets... 

Tsvetkov, Yu.V, Panfilov, S.A., Kliachko, L.I. (1976), Production of Tungsten Powder in Hydrogen Plasma Jet, and Investigations of Properties of the Powder, in Plasma Processes in Metallurgy and Technology of Inorganic Materials, A.A. Baikov Institute of Metallurgy of USSR Academy of Sciences, Nauka (Science), Moscow. 

Fig. 24. Temperature distribution in a DC argon-hydrogen plasma jet. Reprinted from ...

Figure 36 shows the temperature of alumina particles along the axis of a nitrogen hydrogen plasma jet. 

Conversion of Methane to Hydrogen and Carbon black by D.C. Plasma Jet... 

An argon-hydrogen plasma is created in a dc thermal arc (cascaded arc) operated at high pressure 0.5 bar) [556, 559. 560] (the cascaded arc is also employed in IR ellipsometry, providing a well-defined source of intense IR radiation see Section 1.5.4 [343]). As the deposition chamber is at much lower pressure (0.1-0.3 mbar), a plasma jet is created, expanding into the deposition chamber. Near the plasma source silane is injected, and the active plasma species dissociate the silane into radicals and ions. These species can deposit on the substrate, which is positioned further downstream. 

Nitrogen. The gas analysis given in Table IV shows that the nitrogen in the coal was converted to hydrogen cyanide in the plasma jet. The results of experiments on adding nitrogen to the jet are summarized in Table VI. As the concentration of nitrogen in the jet was increased, the conversion of the... 

In the case of hot-filament CVD, refractory metal filaments (e.g., W, Ta, Re, etc.) are electrically heated to very high temperatures (between 2000 and 2700°C) to produce the necessary amount of atomic hydrogen that is necessary for the reasons mentioned above for the synthesis of diamond. Except for combustion flame CVD, hot-filament CVD is considered the simplest of all of the methods and also the most inexpensive. Plasma-jet and laser-assisted CVD methods rely on a plasma torch or laser to attain the very high temperatures that are needed to... 

This system forms highly ionized so-called Penning mixtures [12,13]. The higher excited states of Hj are partly stable and partly unstable, depending on the quantum numbers of the electron present. The stable excited states have, however, only very shallow minima of the potential curves [14]. That is the reason why no spectrum of Hj is observed for the helium plasma jet. The argon excited neutrals, on the other hand, cannot ionize hydrogen atoms or molecules, but could produce excited H2 molecules, which can be detected by optical emission spectroscopy. 

Figure 16.15 The optical emission spectra of argon plasma jets (a) with addition of 10 seem nitrogen and 10 seem hydrogen, (b) with addition of 60 seem nitrogen and 2.7 seem hydrogen, and (c) with pure nitrogen addition, 60 seem nitrogen. The other conditions are 2000 seem argon, 0.64 kW, and 75 Pa.

Figure 18.14 The dependence of excited argon and hydrogen atom emission intensities at an axial position of 2.7 cm from jet inlet on the feed rate of hydrogen added to argon plasma jet 2000 seem argon, 8.0 A arc current.

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