Reaction Characteristics of Self-propagating Ni-Al Nanolayers: Molecular Dynamics Study

Abstract

The Ni-Al nanolayer is exothermic material self-propagated and reacted by thermal or mechanical stimuli from external environment. We have performed molecular dynamics simulations to investigate the reaction characteristics of Ni-Al nanolayers by varying ignition temperature and bilayer thickness with three different compositions (1:1, 3:1, and 1:3) of Ni to Al. The exothermic reaction coordinates of Ni-Al nanolayers were studied to extract the temperature rise, heat of reaction, reaction time, activation energy, and etc. As a result, the reaction kinetics and thermodynamics were quantitatively investigated by various structural and ignition conditions. Further, the reaction mechanisms of Ni-Al nanostripe models, which was initiated by local heating, were theoretically elucidated in terms of thermal and mass diffusion process of Ni and Al. Through this systematic study, the reaction characteristics of Ni-Al nanolayers were theoretically determined and the results can be used to provide an insight into the fabrication of advanced nanolayer systems.