Analysis of Exothermic Reaction Rate for Self Propagation in Combustion Synthesis of Ni3Al Based on Reaction Mechanism of Particles

In SHS, which synthesizes an intermetallic compound from a green mixed powder by propagating the reaction heat, an exothermic reaction rate affects the self-propagation of a combustion wave. The reaction rate in the heat balance equation is expressed in an Arrhenius 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. In my previous paper, microscopic observation of reaction between Ni and Al particles in SHS was performed and the combustion process was fairly well simulated with a resultant spherical shell model. The expression of the exothermic reaction rate using the same model is investigated here. The rate contains physical properties of component particles and chemical reaction rate constant and it varies depending on the conversion rate which indicates the comsumption of Ni particles. Furthermore, the phase transformations in reaction are also taken into consideration.