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

Abstract

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 (Ti) of AlH3 in composites are increased by at least 16 °C, whereas the thermal decomposition peak temperatures (Tp) 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.