FIELD-EFFECTS IN SELF-PROPAGATING SOLID-STATE REACTIONS

The effect of an externally imposed electric field on self-propagating solid-state reactions is described. Above a minimum (threshold) field , the rate of self-propagation reactions (SPR) is roughly linearly dep endent on the magnitude of the applied field. The effect of the field appears to be largely thermal in nature, i.e. through Joule heating. H owever, this effect can be primarily localized in the narrow reaction zone for reaction systems in which the product is relatively non-condu cting. But for cases where the product is relatively conducting, the f ield effect, as judged by the current density distribution is not conf ined. The degree of activation of the reaction by the field in the lat ter case decreases with distance traversed by the wave. Modeling studi es on these two cases have provided results which are in qualitative a greement with the experimental observations. The influence of the fiel d on the nature of the products of the self-propagating reactions is a lso described.