Atomic perspectives revealing the evolution behavior of aluminum nanoparticles in energetic materials

Recent ReaxFF MD studies on pyrolysis and combustion mechanisms of aviation/aerospace fuels and energetic additives

“…In addition, it was also found that although the addition of ANPs increased the heat release of the system and played a catalytic role in the pyrolysis of TATB, it also reduced the yield of gas molecules and increased the number of C/Al clusters. Zhao et al 131 have similar conclusions on the pyrolysis of pentaerythritol tetranitrate (PETN) in the presence of ANPs. In this system, the hot spots in PETN originate from the exothermic oxidation of ANPs.…”

“…Metals, especially aluminum, have high combustion enthalpy, which can increase the combustion temperature of the system, and aluminum combustion products are harmless and low cost, so they are widely used as fuel additives. An in-depth understanding of the pyrolysis or combustion of aluminum itself, [122][123][124][125][126][127][128][129] energetic materials/aluminum composites 112,[130][131][132][133][134][135] and small molecule/aluminum systems 123,134,[136][137][138][139][140] is of great interest.…”

Changes in the state of matter of KCIO4 to improve thermal and combustion properties of Al/MoO3 nanothermite

“…The diffusion-oxidation mechanism is that when the heating rate is low, the pressure gradient affects the diffusion of the central Al, i.e., when nano Al is oxidized, the Al atoms in the nucleus diffuse outward and the oxygen atoms diffuse inward [ 51 , 52 ]. The ion diffusion mechanism suggests that the ignition of Al nanoparticles covered with an oxide layer is mainly due to the internal electric field generated by the alumina layer on the surface, which accelerates the diffusion rate of Al ions through the oxide layer and enhances their diffusion strength.…”

Reaction mechanism of aluminum nanoparticles in explosives under high temperature and high pressure by shock loading

“…Owing to external diffusion of the aluminum atoms, a void forms in the center of the ANPs. Zhao et al 25,26 also found that the reaction of ANPs follows the DOM, and the ANPs are uniformly oxidized. Zhong et al 27 performed molecular dynamics simulation of the reaction of ANPs in RDX at high temperature.…”

“…To understand the reaction mechanism of ANPs under shock loading, the crystal structure of the ANPs was analyzed based on the atomic positions obtained from the molecular dynamics simulation. The radial distribution function (RDF) of the aluminum atoms, mean square displacement (MSD) of the aluminum atoms in the ANP core, and MSDs of the aluminum and oxygen atoms in the oxide shell were calculated 25,42. Snapshots of the ANPs and surrounding explosive molecules at different times for an explosive supercell containing 1 nm ANPs subjected to 3000 m s À1 shock loading are shown in Fig.6(a), in which the colors indicate that the aluminum atoms are in different crystal structures.…”