%0 Journal Article
%T Effects of Electric Field on the SHS Flame Propagation of the Si-C System, Examined by the Use of the Heterogeneous Theory
%A Atsushi Makino
%J Journal of Combustion
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/752068
%X Relevant to the self-propagating high-temperature synthesis (SHS) process, an analytical study has been conducted to investigate the effects of electric field on the combustion behavior because the electric field is indispensable for systems with weak exothermic reactions to sustain flame propagation. In the present study, use has been made of the heterogeneous theory which can satisfactorily account for the premixed mode of the bulk flame propagation supported by the nonpremixed mode of particle consumption. It has been confirmed that, even for the SHS flame propagation under electric field, being well recognized to be facilitated, there exists a limit of flammability, due to heat loss, as is the case for the usual SHS flame propagation. Since the heat loss is closely related to the representative sizes of particles and compacted specimen, this identification provides useful insight into manipulating the SHS flame propagation under electric field, by presenting appropriate combinations of those sizes. A fair degree of agreement has been demonstrated through conducting an experimental comparison, as far as the trend and the approximate magnitude are concerned, suggesting that an essential feature has been captured by the present study. 1. Introduction Self-propagating high-temperature synthesis (SHS) process, by virtue of a strong exothermic reaction that passes through a compacted mixture of particles, as a flame, has attracted special interests as a rapid and economical way in synthesizing inorganic and/or intermetallic compounds [1¨C5]. More than hundreds of kinds of materials, including borides, carbides, and silicides, are reported to be synthesized [1¨C5] by applying this process, while some of them are quite difficult to synthesize in conventional ways. Materials synthesized are now being considered for use as electronic materials, materials resistant to heat, corrosion, and/or wear, and so forth [1¨C5]. Production of functionally graded materials (FGMs) [6], composed of different components with continuous profiles, is also intended. Note also that near-net-shape fabrication can be anticipated because this is a kind of powder metallurgy. The SHS process, applicable to various combinations of solid-solid, solid-liquid, and/or solid-gas systems, as pioneered by the group of Merzhanov and Borovinskaya [7], has also been recognized to present diverse phenomena of the flame propagation, such as pulsating, spinning, and/or repeated combustions, as well as steady propagation, as reviewed [1¨C5, 8, 9]. Among various systems, synthesis of Ti-C system has
%U http://www.hindawi.com/journals/jc/2013/752068/