AUTOWAVE SYNTHESIS OF CAST BINARY SILICIDES OF MOLYBDENUM, TUNGSTEN, NIOBIUM, AND TITANIUM FROM THERMITE MIXTURES
V. A. Gorshkov, P. A. Miloserdov, V. I. Yukhvid
Institute of Structural Macrokinetics and Materials Science, Russian Academy of Sciences, Moscow, 142432 Russia
Keywords: combustion, thermite mixture, gas pressure, temperature and rate of combustion, melting, phase separation, cast silicides
Abstract
The processes of combustion and phase separation in thermite SHS systems in the synthesis of cast composite materials based on the silicides of molybdenum, tungsten, niobium, and titanium in a wide range of ratios between them have been studied. Thermodynamic calculations for the hot MoO3/2Al/2Si and WO3/2Al/2Si systems have shown that the pressure has a the strong effect on the combustion temperature and yield of gaseous products, and for the cold 3Nb2O5/10Al/12Si and 3TiO2/4Al/6Si systems, this effect has not been found. The effect of the ratio of the initial reagents and the activating high-temperature additive (CaO2 + Al) on the combustion and phase-separation parameters have been studied experimentally.
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