Atomic perspective revealing for combustion evolution of nitromethane/nano-aluminum hydride composite

Abstract

Adding aluminum hydride (AlH₃) into energetic materials (EMs) can improve their combustion and energy performance effectively. However, the potential mechanism of AlH₃ on EMs is still unclear. Based on the ReaxFF-lg method, the thermal decomposition of nitromethane/nano-aluminum hydride (NM/nano-AlH₃) composites were studied. The addition of AlH₃ reduces the energy barrier and increases the energy release during the decomposition of NM, accelerates the decomposition of NM. The main way of AlH₃ oxidation involves the capture of O atoms from NM. The results show that AlH₃ content and passivated layer affect the oxidation and hydrogen release of AlH₃. The explosion of small particle size AlH₃ leads to rapid oxidation and hydrogen release. The oxidation of large particle size AlH₃ is dominated by the inward and outward diffusion of O and Al atoms. The products of NM/nano-AlH₃ composites are H₂O, CO₂, N₂ gases, and Al clusters. This work is expected to guide the application of AlH₃ in EMs.

Keywords: Decomposition mechanism; Detonation pressure; Energy release; Nano-AlH(3) particles evolution; Reaction kinetic parameter; ReaxFF.