On a peculiarity of structure formation in combustion of high-caloric metallothermic compounds under microgravity conditions

Abstract

Gravity strongly affects the combustion of highcaloric metallothermic compounds. In these processes, high-temperature heterogeneous melts composed of mutually insoluble components are produced as the products of combustion. Usually, these melts contain a metallic (heavy) and oxide (lighter) phases. In the gravity field, the phase separation takes place on the macroscopic level (the heavy phase precipitates and the lighter phase rises to the surface) and a two-layer (or multilayer) cast product is eventually formed. This phenomenon was used in investigating the processes of the self-propagating high-temperature synthesis in centrifugal separators, in which the gravity effect of phase separation was enhanced [1–3]. Of no less interest is the opposite formulation of the problem: to study how these processes proceed in the weightless state, i.e., without gravity. Earlier, a marked effect of microgravity on combustion processes and structure formation was noted in combustion of element-containing mixtures [4–7].