Revealing the decomposition behavior of hexanitrostilbene and aluminum nanoparticles composites: A reactive molecular dynamics simulation

• Published in: Acta astronautica Vol. 177; pp. 320 - 331
• Main Authors: Zhao, Ying, Zhao, Jiang-Shan, Zhao, Feng-Qi, Xu, Si-Yu, Ju, Xue-Hai
• Format: Journal Article
• Language: English
• Published: Elmsford Elsevier Ltd 01.12.2020; Elsevier BV
• Subjects: Aluminium nanoparticle; Aluminizing; Aluminum; Carbon; Clusters; Composite materials; Decomposition; Decomposition behavior; Decomposition reactions; Detonation; Energy outputs; Hexanitrostilbene; High temperature; Hydrogen; Molecular dynamics; Nanoparticles; Nitrogen atoms; Oxidation; Oxygen; Oxygen atoms; Simulation; Clusters; Aluminium nanoparticle; Decomposition behavior; Energy outputs; Hexanitrostilbene
• ISSN: 0094-5765; 1879-2030
• DOI: 10.1016/j.actaastro.2020.07.042

Hexanitrostilbene plays an important role in aerospace and space technology because of its excellent chemical stability. However, carbon deposition during the explosion seriously affects its detonation performance. A newly parameterized reactive force field was used to simulate the decomposition behavior of nanometer aluminized hexanitrostilbene. Aluminum nanoparticles and the corresponding surface oxidized ones were mixtured with the hexanitrostilbene to build nanometer aluminized composites. The simulation results show that aluminum nanoparticles lead to an earlier decomposition of hexanitrostilbene in a new way. Aluminum nanoparticles follow diffusion oxidation theory in the heating. At high temperatures, Aluminum nanoparticle quickly splits and exposes active aluminum to participate in the reaction. The presence of oxide layer in surface oxidized aluminum nanoparticle is less attractive to oxygen, carbon and nitrogen atoms, and surface oxidized aluminum nanoparticle is difficult to split into small particles during ignition and detonation. Aluminum nanoparticles prevent the formation of larger carbon clusters and cause hydrogen and oxygen atoms escape from carbon clusters. This is the main reason for the increasing detonation pressure and energy outputs of nanometer aluminized Hexanitrostilbene. Adiabatic simulation shows that nanometer aluminized hexanitrostilbene decomposes faster and releases more energy than pure hexanitrostilbene. This work provides insights for the application of aluminized hexanitrostilbene composites in aerospace. •ReaxFF-lg is used to simulate the thermal decomposition of nano-aluminized HNS.•Al nanoparticles lead to an earlier decomposition of HNS in a new pathway.•Evolution behavior of nano-Al during heating follows diffusion oxidation theory.•Nano-Al prevents the agglomeration of carbon.•Gas production and energy outputs of nano-aluminized HNS are greatly improved.