ANALYSIS OF COMBUSTION WAVE IN SELF-PROPAGATING HIGH-TEMPERATURE SYNTHESIS OF NI-AL INTERMETALLIC COMPOUNDS

The propagating behavior of combustion wave is mathematically analyzed in the synthesizing process of an intermetallic compound from a Ni/Al green mixed powder compact by the heat of reaction. The exothermic reaction rate in the heat balance equation is usually expressed by an Arrhenieus style as an empirical formula. However, the basis for this expression is not clear and this assumption seems to treat a powder compact as a continuum. A preliminary experiment disclosed the combustion process was fairly well simulated with a spherical shell model based on the reaction between particles. The expression of the exothermic reaction rate using this model is applied to this analysis. The characteristics of propagation of combustion wave are affected by preheating condition of compact, heat of ignition, power particle size etc.