High-Energy Composite Fuels with Improved Combustion Efficiency by Using AlH₃ Embedded with Al Particles

Abstract

Aluminum hydride (AlH3) has attracted much attention due to its potential to replace aluminum (Al) as a novel energetic material in solid propellants. In this research, ammonium perchlorate (AP) and perfluoropolyether (PFPE) as functionalized coatings and a combination of acoustic resonance and spray drying technology have been employed to prepare AlH3@Al@AP (AHAPs) and AlH3@Al@AP@PFPE (AHAPs-F) energetic composite particles. The formulations of composite propellants and modified AlH3 particles were designed and fabricated. Their thermal reactivity, reaction heat, density, vacuum stability, combustion performance, and condensed combustion products (CCPs) have been systematically investigated. The results show that the solid propellants containing AHAPs (SP13) and AHAPs-F (SP14) composites can significantly enhance the reactivity and energy output compared to conventional solid propellants with the mechanical mixture Al/AlH3 (SP12). In particular, the total heat releases of SP13 and SP14 are almost 1.2 and 1.7 times higher than those of conventional ones (SP12, 1442 J g–1), respectively. Among the AlH3-based propellants, SP14 propellants exhibit the highest reaction heat of 5887 J g–1, the most intensive flame radiation of 31.4 × 103, and the highest combustion wave temperature of 2495 °C. Moreover, the particle size distribution of CCPs from SP14 propellants is much narrower and smaller than that of SP12, resulting in higher combustion efficiency.

Ab Initio Driven Exploration on the Thermal Properties of Al–Li Alloy

“…Metal additives, particularly aluminum (Al), are commonly used as the primary energy source in advanced energetic and propellent systems to enhance energy density and heat release, while also suppressing oscillating combustion. − However, the naturally occurring passive oxide layer on the surface of Al particles presents a challenge due to its high melting point (2327 K), which hinders immediate ignition and complete combustion . Additionally, molten Al particles tend to merge and form liquid droplets on the propellant surface, exacerbating the agglomeration of Al and contributing to a loss phenomenon known as two-phase loss, ultimately reducing the specific impulse. , These unfavorable factors significantly restrict the energy release process and combustion performance of the propellant.…”