Self-propagating high-temperature synthesis as a means of obtaining composites under conditions of joule energy dissipation

High-Temperature Combustion Synthesis: Generation of Electromagnetic Radiation and the Effect of External Electromagnetic Fields (Review)

“…Yet, even a weak Joule action can significantly affect the coefficient of temperature sensitivity of the front-propagation velocity and, thus, stability of the combustion mode. It was found [33,55,65,66] that, other conditions being identical, the Joule heat release localized in reaction products and/or in the front stabilizes propagation of the high-temperature synthesis wave, whereas the Joule heat release localized in the initial mixture initiates instability development and can lead to the thermal explosion. The results of [33,55,65,66] on stability are in agreement with the concepts of the classical theory of combustion [67,68].…”

“…It was found [33,55,65,66] that, other conditions being identical, the Joule heat release localized in reaction products and/or in the front stabilizes propagation of the high-temperature synthesis wave, whereas the Joule heat release localized in the initial mixture initiates instability development and can lead to the thermal explosion. The results of [33,55,65,66] on stability are in agreement with the concepts of the classical theory of combustion [67,68]. Two important conclusions were made: first, it is principally possible to control the synthesis, and such control does not require high powers of electric heat release, as in the ETE, EPTS, and FACS methods; second, the greatest effect of the action and, hence, the possibility of control occur at the limit of propagation of the synthesis wave.…”

“…The conclusion drawn in [33,55,65,66] about the greatest controlling Joule effect at the limit of propagation of the synthesis wave initiated the study [78,79] of the spin combustion mode heated locally by external electromagnetic radiation of moderate power. Radiation localization was caused by an exponential growth of conductivity with temperature owing to dissolution or evaporation of oxide films from the medium particles.…”

“…Generally, the theory of propagation of a hightemperature synthesis wave under conditions of an additional Joule heating by an external electric field originated in works on the influence of currents with a constant density and intensity [33,55,65,66]. Two methods of application of the external field were considered: along the wave direction (with a constant current density) and across the wave direction (with a constant voltage); quasi-steady regimes of synthesis propagation, where the wave front has enough time to fit the time-dependent temperatures of the products and initial mixture, were examined.…”

Effect of an Electrostatic Field on Self-Propagating High-Temperature Synthesis of Manganese Ferrite

“…In these studies, the effect of an electric field on the process was usually associated with the occurrence of a heat source additional to that provided by the chemical reaction, i.e., Joule heating of the sample, which ensures a steadystate heterogeneous combustion regime even for weakly exothermic systems [4]. Although theoretical studies of the thermal aspects of the electric-field effect on the SHS process started as early as in [5,6], this phenomenon has not been completely understood so far.…”