Dynamics of thermal explosion in the postinduction period

Dynamics of phase-formation processes during self-propagating high-temperature synthesis in the thermal explosion regime

“…Thus, the formation of the structure and phase composition of the final product is largely determined by the dynamics of induction processes. At the same time, the majority of heterogeneous systems interacts in the presence of the liquid phase, which is a chemically active component (this fact is ignored in [6]; hence, the results calculated by this model are also valid, for instance, for gas suspensions). In this case, the dynamics of melting during heating of the mixture should be taken into account if the characteristic times of heating and melting are commensurable (see the classical papers [7,8]); otherwise, melting precedes the thermal explosion.…”

“…(6) and (7): Biot criterion of the system Bi = αR 1 /λ 3 , ambient temperature Θ * , effective heat-release coefficient α, thermal conductivities λ 1 -λ 3 in the regions 1-3, and ω = 7) were aimed at elucidating the specific features of self-heating and formation of the synthesis product in the course of the thermal explosion and also conditions for obtaining a single-phase product in the volume of the cylindrical reactor, depending on the external conditions of synthesis.…”

“…One of the basic problems of technological combustion is a correct choice of synthesis regimes for obtaining products with required compositions and properties. For this reason, the interest in self-propagating high-temperature synthesis (SHS) in the thermal explosion regime [2,3] has increased, because the process in this regime can be controlled by changing the ambient conditions [4,5]. From this viewpoint, an important aspect of technological combustion is obtaining a singlephase product of synthesis in the entire volume of the 1 Polzunov Altai State Technical University, Barnaul 656038; vyfilimonov@rambler.ru.…”

“…It was demonstrated by methods of mathematical modeling [6] that the thermal explosion process with all values of parameters (both internal parameters characterizing the heat release kinetics and external parameters characterizing energy exchange with the ambient medium) is accompanied by the formation of the combustion front determined by inhomogeneity of temperature and conversion depth fields during the induction period. Thus, the formation of the structure and phase composition of the final product is largely determined by the dynamics of induction processes.…”

“…determined by the particular features of the phase diagram of the system. In this aspect, the use of effective kinetic functions [6,9], being universal to a certain extent, provides only a schematic description of the real process, because the specific features of interaction of a particular system are ignored, and these features, in turn, are determined by the structure of the phase diagram. In the present paper, we consider interactions in heterogeneous systems characterized by the phase diagram with a congruently melting intermediate phase with weak solubility of the highmelting component in the melt of the low-melting component.…”