Thermal decomposition and combustion behavior of the core-shell Al@AP composite embedded with CuO as a catalyst.

• Thermal reactivity of core–shell Al@AP and Al@AP/CuO composites were characterized. • The decomposition kinetics and gaseous products of composites were fully identified. • The Al@AP and Al@AP/CuO composites demonstrated better combustion performance. • Mutual interactions of Al@AP embedded with CuO under high temperature were clarified. Conventional solid propellants suffer from undesirable combustion performance due to the poor mass and heat transfer between metal fuels and oxidizers, as well as a lack of catalytic active sites between the catalyst and catalyzed objects. Embedding metal fuels and catalysts within the oxidizer has shown promise in improving the overall combustion performance of HTPB/AP/Al and HTPB/AP/RDX/Al composite solid propellants. However, the underlying mechanisms responsible for this enhancement remain to be further understood. In this study, we investigated the reactivities of core–shell Al@AP and Al@AP/CuO composites using thermal analysis and combustion diagnostic techniques. The results demonstrated that the decomposition of AP was promoted, as evidenced by a lower peak temperature (415.2–334.7 ℃), higher total heat release (116.4–720.8 J·g−1), a transition in the decomposition physical model from the random nucleation and 2D/3D growth of nuclei model to the auto-catalytic model, and increased generation of NO 2. Furthermore, the Al@AP/CuO propellant pellet exhibited a more stable flame without agglomeration, and the condensed combustion products (CCPs) contained a lower amount of unreacted Al compared to that of conventional mixtures. These findings highlighted the potential of core–shell Al@AP and Al@AP/CuO composites as replacements for discrete ingredients of solid propellants, thereby offering improved performance for next-generation propulsion systems. [ABSTRACT FROM AUTHOR]