Macrokinetics of Combustion of Powder and Granulated Titanium Mixtures with Different Allotropic Forms of Carbon
B. S. Seplyarskii, R. A. Kochetkov, T. G. Lisina, N. I. Abzalov
Merzhanov Institute of Structural Macrokinetics and Materials Science, Russian Academy of Sciences, Chernogolovka, 142432 Russia
Keywords: SHS, macrokinetics, burning rate, powder mixtures, granules, impurity gas release, titanium particle size, soot, graphite
Abstract
Even a slight change in the content of impurity gases during a self-propagating high-temperature synthesis can lead to a change in the combustion regime and the characteristics of the target products. In this work, the dependence of the burning rate of Ti + C granular mixtures on a titanium particle size is determined for the first time, and the effect of impurity gas evolution when using various allotropic modifications of carbon (graphite/soot) is studied. Experimental results are analyzed using the convective-conductive combustion model, which explains the strong influence of impurity gas release on the front velocity. Interaction rate of the components becomes a key factor for granular mixtures in which the influence of impurity gases is leveled. Experiments show that the burning rates of granular mixtures of titanium with soot are noticeably higher than the burning rates of a mixture of titanium with graphite. The curves approximating the dependence of the burning rate of a granular mixture of titanium and graphite on the size of titanium particles correspond to the linear law of interaction of the initial components. The interaction in a mixture of titanium and soot occurs according to the parabolic law.
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