Methods for controlling the synthesis of the submicron (including nanosized) powder of titanium dioxide (titania, TiO 2 ) in a setup with a plasmachemical flow reactor were investigated. The synthesis of titania particles from gaseous titanium tetrachloride (TiCl 4 ) in the plasmachemical reactor by the chloride method was experimentally studied. The processes of formation and growth of particles depending on the type of the plasmaforming gas, flow rates of TiCl 4 ; and the quenching gas (air), reactor length, and mean-mass temperature in the reaction zone were considered. When using nitrogen as heat-carrying gas, a new approach of titania powder synthesis based on combining of reaction zone and quenching zone has been applied. Under these nonequilibrium conditions and substantial temperature gradients, this method enabled us to synthesize reproducibly ultrafine titania powders (30-50 nm) with a high content (80-87%) of metastable anatase crystal lattice. The results reveal that the powder properties can be efficiently controlled, i.e., one setup can produce titania with a required particle size and a type of the crystal lattice: anatase (A) or rutile (R). The experimental data are found to agree well with the results of numerical calculations.

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This article presents a short description of the DC plasma torch "PNK-50" structural features (ITAM SB RAS, Novosibirsk) used for spraying of functional coatings with powder materials as well as gives the results of thermophysical and technological studies of spraying regimes. We present preliminary results of the plasma torch supersonic modification development and the results of industrial approbation of the plasma torch and of multi-purposes functional coatings deposition processes.

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