Discharge plasma-beam

Vapor—vapor reactions (14,16,17) are responsible for the majority of ceramic powders produced by vapor-phase synthesis. This process iavolves heating two or more vapor species which react to form the desired product powder. Reactant gases can be heated ia a resistance furnace, ia a glow discharge plasma at reduced pressure, or by a laser beam. Titania [13463-67-7] Ti02, siUca, siUcon carbide, and siUcon nitride, Si N, are among some of the technologically important ceramic powders produced by vapor—vapor reactions. 

Table I includes results concerning a-C(N) H film deposition by ECRRF dual plasmas [49]. Despite the higher ionization and fragmentation of ECRRF plasmas, the results obtained are similar to those of glow-discharge plasmas. This is also the case for deposition performed by highly ionized methods such as plasma beam deposition [39].

A plasma is a partially ionized gas composed of ions, electrons and neutral species. It is a state of matter that can be created by such diverse techniques as flames, electrical discharges, electron beams, lasers or nuclear fusion. The technique of most interest to plasma polymerization is the glow discharge, in which free electrons gain energy from an imposed electrical field, and subsequently loses it through collisions with neutral molecules in the gas. The transfer of energy to gas molecules leads to the formation of a host of chemically reactive species, some of which become precursors to the plasma polymerization reaction. 

The different versions in existence may be classified according to Spalvins [386] as to the media, evaporation source and mode of transport into two categories low vacuum ion plating (self-sustained glow discharge plasma) resistance evaporation electron-beam evaporation induction evaporation sputtering... 

On the one hand, the cross sections that are derived from swarm data cannot be expected to possess the accuracy and detailed structure of good beam measurements or ab initio calculations, but, on the other hand, they naturally produce (if the procedure is carried out well) cross-section sets that accurately reproduce the macroscopic observables that are relevant to real plasmas. Such quantities are drift velocities or mobilities, which are directly connected with the power deposition in a discharge plasma, diffusion coefficients, and attachment and ionization coefficients, which are intimately related to the ionization balance of a plasma. These are the quantities that are used directly in most plasma models and that are measured in laboratory plasmas. 

Figure 5-51. CO2 dissociation in plasma-beam discharge. Partial pressures of the dissociation products as function of electron beam power (1) CO2 (2) CO (3)02.

Experiments with Complete CO2 Dissociation in Stationary Plasma-Beam Discharge... 

J/em when the beam power is about 1.5 kW, which is far from the optimal i v values (see Section 5.3). The energy efficiency of CO2 dissociation was calcrrlated in the experiments with plasma-beam discharge rrsing the following formula, which takes into accormt both incomplete and complete decomposition ... 

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