Enhanced stability and combustion performance of AlH₃ in combination with commonly used oxidizers

Aluminum hydride (AlH₃), as a promising fuel, has been utilized to improve the energy performance of propellants. Moreover, the inherent compatibility and mutual interaction between AlH₃ and the commonly used oxidizers of solid propellants are the basics of propellant formulation design. Herein, the homogenous composites of AlH₃/oxidizer have been prepared by the in-situ recrystallization method, and then their thermal stability, compatibility, and ignition performance have been investigated. The initial decomposition temperatures (T_i) of AlH₃ in composites are increased by at least 16 °C, whereas the thermal decomposition peak temperatures (T_p) of involved oxidizers are lower than that of their pure state. The compatibility tests showed that AlH₃ is compatible with the mentioned oxidizers. In particular, the induction time of the dehydrogenation of AlH₃ in presence of these oxidizers is improved by almost 1.2 times that of raw AlH₃, which means that the oxidizers have an unexpected strong stabilization effect on AlH₃ due to strong hydrogen bonding. Moreover, the optimized contents of AlH₃ in AlH₃/HMX, AlH₃/CL-20, and AlH₃/AP composites have been determined to be 45 %, 40 %, and 33 %, which have the maximum flame temperatures of 1275.3, 1440.4, and 1616.8 °C, respectively. Besides, AlH₃/CL-20 has the strongest flame radiation intensity (18.5 K) and shortest ignition delay time (32.2 ms) among the involved composites.