[en] A procedure for simulating gas-dynamic and thermal conditions during the conversion in a radiofrequency induction (RFI) plasma reactor has been developed. The model includes a turbulent flow of a mixture of ideal viscous compressible gases, taking into account inductive heating of the gas through heat conduction, convection, and radiation, considering the effect of the electromagnetic field force on the plasma motion. The formation of powder particles agrees with the results of thermodynamic calculations; the distribution of particles in the flow is described by the diffusion mechanism. The results of the simulation of the conversion of volatile boron chloride and boron fluoride in an RFI plasma torch with vortex-stabilized flow are presented.

[en] The plasma-chemical reduction was studied experimentally of molybdenum, sulfur and germanium fluorides with different isotopic composition by hydrogen in plasmas sustained by inductively coupled (IC) and capacitively-coupled (CC) RF discharges. The emission spectra of plasmas recorded under different experimental conditions are discussed. Reaction mechanisms are proposed. In the case of "9"8MoF_6 reduction in CCP, the combined radical-atomic mechanism including intermediate MoF_3 resulting in bulk and powder "9"8Mo formation was established. In the emission spectrum of the "3"2SF_6 + H_2 system in ICP at 0.2 Torr, only lines assigned to SiF_2, SiF and F_2 "* originating from the decomposition of "3"2SF_6 and a fast reaction of its products with the reactor's quartz walls were observed. Due to this etching process, the yield of "3"2S was moderate. Increasing the pressure in the reactor above 1 Torr resulted in an increase of the "3"2S yield. The mechanism of "7"2GeF_4 reduction depends on the pressure and plasma type. At 0.25 Torr in ICP, a "7"2Ge deposit was formed via the "7"2GeF radical; however, at 3.5 Torr in CCP, the mechanism changed to a molecular one. Results of the study of the structure and the isotopic and chemical purity of isotope samples obtained are briefly presented. (paper)

[en] The main operating modes of a radiofrequency induction plasma torch with a vortex stabilization of the atmospheric-pressure gas discharge at have been studied in an argon-hydrogen mixture in the range of Ar/H₂ = 12–4. The dependences of the electron temperature T_e and number density n_e on the Ar/H₂ ratio have been experimentally studied. It has been found that the electron temperature and concentration in pure argon plasma are 0.88 eV and 7.6 × 10¹⁴ cm⁻³, respectively. When the Ar/H₂ ratio decreases, the electron temperature decreases to 0.42 eV, and the electron number density is 8 × 10¹² cm⁻³. The calorimetric method used to estimate the gas temperature T_g, has given a value of 2500 K. The process of BCl₃ reduction with hydrogen has been studied at the implemented operating modes of the induction plasma torch. The main products of the reduction of boron trichloride are a polycrystalline boron powder and dichloroborane. The morphology of boron and its phase composition and impurities have been studied. The average particle size of the boron powder is 200 nm.

[en] Plasma-chemical reduction of silicon and germanium fluorides with different isotopic composition by hydrogen at low pressure was studied experimentally. Samples of silicon of natural isotopic composition and germanium polycrystalline 'flakes' with isotopic numbers 72 and 74 were obtained and used to grow poly- and single crystals by the Czochralski method. The contamination by the most important impurities in each type of silicon and germanium was determined. A chemical mechanism for the reduction process was also proposed. It was shown that the direct method of reduction of isotopically-enriched fluorides is suitable for obtaining small amounts of high-purity isotopes of those elements to be used in unique physical experiments.