How sub-atmospheric pressure regulates combustion in aluminum-based energetic materials: A comparative study of condensed-phase and gas-phase pathways
Year: 2026
Type: article
Abstract: The energy release and combustion behavior of aluminum-based energetic materials under sub-atmospheric pressure are critical for aerospace and high-altitude applications. However, a systematic understanding of how pressure regulates different reaction types remains incomplete. In this study, a synchronized multi-diagnostic platform was employed to comparatively investigate the pressure-dependent energy output and combustion behavior of two representative systems: Al/MoO 3 (condensed-phase dominated) and Al/KClO 4 (gas-phase dominated). For Al/MoO 3 , decreasing pressure has a negligible influence on combustion under unconfined conditions; however, a notable transition in ignition delay time and flame diffusion dynamics is observed at 1 kPa. In contrast, under confined conditions, it significantly reduces burning rate and high-temperature reaction zone, which is further validated by numerical simulations. For Al/KClO 4 , decreasing pressure leads to the deterioration of both ignition and combustion performance, ultimately preventing sustained combustion below a critical pressure. The marked drop in the concentrations of AlO and K I observed via emission spectroscopy demonstrates the suppression of gas-phase oxidation. This fundamental disparity originates from the controlling role of pressure on oxidizer decomposition, oxygen diffusion, and gas–solid reaction kinetics. This work clarifies the distinct pressure-dependent behavior of Al-based energetic materials with different reaction mechanisms and establishes a diagnostic framework for tailoring the combustion performance of energetic materials in low-pressure environments.
Source: Defence Technology
Institution: Nanjing University of Science and Technology
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7221535252