Thermal decomposition reaction mechanism and combustion performance of AlH3/AP energetic composite

To study the reaction mechanism and the optimal energy release ratio of the AlH3/AP energetic composite particles, we prepared six different AlH3/AP energetic composites by wet-mixing after the ultrafine treatment of AP by a jet refiner based on the solvent/non-solvent method. The thermal reaction kinetics and the microscopic reaction mechanism of composites were characterized by TG-DSC and TG-MS-IR, respectively. The combustion characteristics were photographed using a high-speed camera. The results show that the LTD Ea first decreases and then increases with the AlH3 content in the composite samples, finally reaching a stable value, while the HTD Ea first decreases and then becomes stable. When the content of AlH3 in the composite sample is higher than 15%, the sample exhibits higher LTD Ea (about 120 kJ mol−1) and lower HTD Ea (about 125 kJ mol−1) than pure AP, and the thermal stability and energy utilization ratio are significantly improved. The change in the mechanism of thermal reaction kinetics is explained by the influence of the AlH3 decomposition products on the catalytic effect and adsorption hindrance of AP in the microscopic environment. Combined with isobaric combustion parameters and the flame phenomenon, the composite sample exhibits the best energy release effect when the content of AlH3 in the propellant is 20%. This study provides a theoretical basis for applying the new solid-propellant formula in rocket engines.