Thermal oxidation, ignition, and combustion characterization of AP-, LP-, and KN- coated multi-metal composite powders in Air/H2O environments

Studying the ignition and combustion performances of modified aluminum-based metallic fuels in variable oxidizing atmospheres is highly important for large-scale space exploration. In this study, Al–B–Mg multi-metal composite powders (MMP) were prepared using the mechanical ball-milling method.It was coated respectively by ammonium perchlorate (AP), lithium perchlorate (LP), and potassium nitrate (KN) to obtain modified multi-metal composite powder fuels (AP@MMP, LP@MMP, and KN@MMP, respectively) by a recrystallization method. The samples were characterized and their thermal oxidation, ignition and combustion processes were investigated through a TG and laser-ignition experiment under Air/H₂O environments. The results show that the MMP samples can potentially be called pure aluminum substitutes. All three samples exhibit fast ignition characteristics with ignition delay times of 2.95–6.75 ms in air. AP@MMP exhibits the highest ignition speed. The thermal oxidation, ignition, and combustion properties of all samples decayed with increasing water content in the atmosphere (Air→Air+H₂O→H₂O). AP@MMP exhibits a significantly more intense and stable combustion overall than LP@MMP and KN@MMP. This study expands the direction and application range of aluminum-based composite metal fuels, guiding their applications in Air/H₂O environments.