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Abstract: In this work, experiments with stoichiometric WO3 +3Zn mixture, diluted with NaCl, were conducted for nanostructured tungsten synthesis. The reaction samples, preheated until 720K, were self-ignited and reacted in the steady combustion regime. The temperature–time profiles in the combustion wave were collected over the NaCl interval from 1 to 6mol, and the values of the combustion parameters (T c , U c ) were evaluated. From these profiles the spatial distributions of heat generation rate ϕ(x) and degree of conversion η(x) in the combustion wave were received at different k values. The calculated activation energy for the combustion process was E =55±2kJmol−1. After the reduction experiments, pure tungsten nanopowder with particle size from 200 to 50nm was obtained depending on NaCl concentration. [Copyright &y& Elsevier]

The combustion characteristics of a MoO3+SiO2+Mg system diluted with sodium chloride have been studied in order to synthesize molybdenum disilicide (MoSi2) fine powders. The effect of processing variables, including the sodium chloride content and the reactants proportion on the phase composition and microstructure of the final products, was obtained. Both the combustion temperature and the wave velocity decreased with an increase in the amount of sodium chloride. With the appropriate processing parameters, the reacted product consisted of solid crystalline MoSi2, and an MgO phase was prepared in the molten sodium halide matrix at 1100°–1350°C. The final product purification resulted in MoSi2 powder with a particle size of 100–500 nm. The mechanism of the MoSi2 formation in the sodium chloride matrix is discussed by analyzing the phase evaluation in the extinguished combustion wave. [ABSTRACT FROM AUTHOR]