Kinetics of Mg₂Ni Combustion Synthesis

Abstract

In this paper, reaction kinetics in the combustion synthesis of Mg₂Ni was discussed, in which physical and chemical changes of the samples during combustion synthesis were observed and identified by Scanning Electron Microscope (SEM), Electron Probe X-ray Microanalyzer (EPMA) and X-ray diffraction, and a rate equation of solid phase reaction was derived, based on the data measured by Differential Scanning Calorimeter (DSC). The SEM observation demonstrated that the synthesis reaction of Mg₂Ni proceeds uniformly rather than topochemically, and an intermediate phase dose not exist during combustion synthesis. The synthesis reaction was accelerated by liquid generation of eutectic-composition. As a result, the rate equation of the sample was expressed by the form of a second-order irreversible equation, k(1−f)², with the change of the frequency factor, and then it simulated reasonably the DSC curves of combustion synthesis.