Cobalt-Based Metal Hybrid Encapsulated Micro-Aluminum for Tailoring Combustion in Composite Solid Propellants

en This link goes to a English section zh This link goes to a Chinese section To address the issues of aluminum (Al) powder agglomeration during combustion and low oxidizer decomposition efficiency in composite solid propellants, this study utilized in situ self-assembly technology to prepare cobalt-based hybrid-coated modified Al powder (Al@CZ). It systematically investigated its regulatory mechanism on the combustion performance of ammonium perchlorate (AP) and ammonium dinitramide (ADN)-based propellants. Characterization results indicate that Co 2+ and 2-methylimidazole form an amorphous coating layer at the dopamine polymerization interface, with variable thickness accompanied by a gradient of Co 2+ loading. Thermal analysis shows that the modified Al may trigger a thermite reaction at the interface in air, reducing the high-temperature oxidation peak. The modified Al exhibits significant catalytic efficiency for the high-temperature decomposition of AP, with the activation energy reduced by up to 34.7% and the peak temperature advanced by 78°C. However, its catalytic effect on ADN is relatively weak. In the propellant system, Al@CZ reduces the width of the exothermic peak of AP-based propellants, increases the burning rate by 10.4%, and decreases the median particle size of the condensed-phase products by 92.1%; for ADN-based propellants, it significantly improves combustion stability, with the maximum pressure increasing by 1.1 times and the pressure rise rate improving by 6.4 times. Combustion mechanism analysis confirms that the coating accelerates Al core oxidation and reduces combustion surface residence time through the synergistic effect of catalytic decomposition of oxidants and interfacial thermite reactions, effectively suppressing molten agglomeration. This study provides a new strategy for controllable combustion regulation in high-energy solid propellants. 摘要 en This link goes to a English section zh This link goes to a Chinese section 为解决复合固体推进剂中铝粉燃烧团聚及氧化剂热分解效率低的问题, 本研究采用原位自组装技术制备了钴基杂化改性铝 (Al@CZ) , 系统研究了改性铝对高氯酸铵 (AP) 和二硝酰胺铵 (ADN) 推进剂燃烧性能的调控机制。测试结果表明, Co 2+ 与2-甲基咪唑在多巴胺聚合界面形成非晶包覆层, 其厚度随Co 2+ 负载量梯度变化。热分析显示, 改性铝粉在空气中可能引发界面铝热反应, 从而降低高温氧化峰值。改性铝对AP高温分解展现显著催化效率, 使活化能降低34.7%, 峰值温度提前78°C。但其对ADN的催化效果相对较弱。在推进剂体系中, Al@CZ可缩短AP基推进剂放热峰宽, 使燃烧速率提升10.4%, 并使凝结相产物中值粒径缩小92.1%; 对于ADN基推进剂, 显著改善了燃烧稳定性, 最大压力提升1.1倍, 增压速率提高6.4倍。燃烧机理分析证实, 该包覆层通过催化氧化剂分解与界面铝热反应的协同作用, 加速铝芯氧化并缩短熔融铝在燃面停留的时间, 有效抑制熔融聚结。本研究为界面工程调控固体推进剂的燃烧提供了新策略。