Papers by Keyword: Plasma Chemistry

Abstract: The results of studies to determine the parameters affecting the morphology of the particle formation in certain conditions plasma chemical synthesis are present. On the example of oxides of cerium and yttrium were determined kinetic characteristics of plasmachemical process for their preparation, calculated characteristic times of the main stages occurring in the plasma-chemical reactor (t₁, t₂, t₃, t₄). Have been proposed parameter K₀, characterizing the modes of hollow and solid particles formation and determining the process of salt diffusion in the droplet volume and solvent evaporate from the surface.

Abstract: The process of carbon dioxide reforming of hydrocarbon feedstock (like natural gas, coal, petroleum coke, residual oil, glycerine, etc) for hydrogen production has attracted great attention from both environmental and industrial perspectives. The plasma chemical reactor for study the CO₂ reforming of hydrocarbon gaseous feedstock is presented. The reactor consists of a DC plasma torch coupled to a compact quenching chamber. The linear plasma torch operates with a reverse vortex flow and hollow blind-end cathode for enhancing the thermal efficiency and enthalpy of the plasma jet. The quenching chamber consists of a set of refrigerated discs equipped with flow turbulent flow generator. Estimated quenching rates are up to 10⁷-10⁸ K/s. Electrical and thermal characteristics of the plasma-chemical reactor torch as well as the energy efficiency of the process are presented.

Abstract: Ceramics based on nanosized plasma chemistry Si3N4 powder compositions s (30-100 nm) is processed by activated pressureless sintering, hot pressing and hot isostatic pressing. Microstructure characterization of the obtained materials by means o light and scanning microscopy revealed no correlation between microstructure and the bulk consolidation method . Average grain size in all cases was 200-500 nm. Comparative characterization of the physical and mechanical behavior of the analyzed samples showed the following results: relative density - over 99 %, flexural strength – over 700 MPa, Vickers hardness - 16-17GPa, fracture toughness – 6.5-7.4 MPa·m1/2. The activated pressureless sintered samples demonstrated physical and mechanical behavior comparable to the samples consolidated by other methods. Activated pressureless sintering of nanosized plasma chemistry Si3N4 powders led to considerable economic advantages in processing Si3N4 spherical rotation bodies for hybrid roller bearings and cutting tools. Silicon nitride (Si3N4)-based structural ceramics is widely studied and used for over half a century due to its unique properties: low density, combined with high strength and wear-resistance, high decomposition temperature, high oxidation resistance, low friction coefficient and high resistance to chemical corrosion[1].