Abstract Aluminum (Al) has been widely used in solid composite propellants (SCPs) to increase the specific impulse. However, Al always subjects to coalescence, sintering to large agglomerations during combustion of SCPs resulting in larger two-phase flow losses. Herein, core-shell μ-Al@M(IO3)x composites have designed and synthesized as a replacement for micron-sized Al (μ-Al) in the Al/AP/RDX/HTPB propellant with tunable combustion behavior. The results show the thermal reactivity and heat releases of SCP are largely enhanced by using these novel metal-based composites. With the inclusion of μ-Al@EGCG@Fe(IO3)3 (EGCG: Epigallocatechin gallate), the major exothermic peak is reduced by 29.1 °C compared to the reference propellant with a heat release increase up to 5475 J g−1, exceeding that of the reference sample (86 J g−1 higher). The burn rates are increased with the inclusion of μ-Al@(MIO3)x, while the pressure exponent is higher. The SCP-1 (0.3), SCP-2 (0.18) and SCP-4 (0.25) that have relatively low pressure exponent and high burn rates are good candidates for future applications. The major condensed combustion products (CCPs) of these SCPs are Al2O3, Al2.81O3.56N0.44, Al4C3, Al2OC, AlN and C7H18ClN. The agglomeration can be reduced with a minor inclusion of μ-Al@M(IO3)x due to the enhanced interfacial reactions, and the average CCP sizes (0.5 μm for SCP-1 and SCP-4) are even smaller than that of initial μ-Al (1.2 μm).

中文翻译：

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含有核壳Al@M(IO3)亚稳态复合材料的复合推进剂的燃烧性能

摘要 铝（Al）已广泛用于固体复合推进剂（SCPs）以增加比冲。然而，铝总是发生聚结，在 SCP 燃烧过程中烧结成大团块，导致更大的两相流动损失。在此，核壳μ-Al@M(IO3)x 复合材料已设计和合成以替代具有可调燃烧行为的 Al/AP/RDX/HTPB 推进剂中的微米级 Al (μ-Al)。结果表明，通过使用这些新型金属基复合材料，SCP 的热反应性和热释放大大增强。由于包含 μ-Al@EGCG@Fe(IO3)3（EGCG：表没食子儿茶素没食子酸酯），与参考推进剂相比，主要放热峰降低了 29.1 °C，热释放增加了 5475 J g-1，超过参考样品（高 86 J g-1）。随着μ-Al@(MIO3)x 的加入，燃烧速率增加，而压力指数更高。具有相对较低压力指数和高燃烧率的 SCP-1 (0.3)、SCP-2 (0.18) 和 SCP-4 (0.25) 是未来应用的良好候选者。这些 SCP 的主要冷凝燃烧产物 (CCP) 是 Al2O3、Al2.81O3.56N0.44、Al4C3、Al2OC、AlN 和 C7H18ClN。由于界面反应增强，微量加入 μ-Al@M(IO3)x 可以减少团聚，平均 CCP 尺寸（SCP-1 和 SCP-4 为 0.5 μm）甚至比初始尺寸更小μ-Al (1.2 μm)。这些 SCP 的主要冷凝燃烧产物 (CCP) 是 Al2O3、Al2.81O3.56N0.44、Al4C3、Al2OC、AlN 和 C7H18ClN。由于界面反应增强，微量加入 μ-Al@M(IO3)x 可以减少团聚，平均 CCP 尺寸（SCP-1 和 SCP-4 为 0.5 μm）甚至比初始尺寸更小μ-Al (1.2 μm)。这些 SCP 的主要冷凝燃烧产物 (CCP) 是 Al2O3、Al2.81O3.56N0.44、Al4C3、Al2OC、AlN 和 C7H18ClN。由于界面反应增强，微量加入 μ-Al@M(IO3)x 可以减少团聚，平均 CCP 尺寸（SCP-1 和 SCP-4 为 0.5 μm）甚至比初始尺寸更小μ-Al (1.2 μm)。