Micron-Scale Aluminum Coated with Various Types of Metallic Nanoparticles and Its Combustion Performance

In this study, a new composite material [Quaternary]/μAl (i.e., [nCu+nNi+nCo+nFe]/μAl) was synthesized by coating micron-scale Al with Fe, Co, Cu, and Ni catalysts for the displacement reaction. Fe, Co, Cu, and Ni metal particles form a nanoparticle interfacial layer on the surface of μAl, which facilitates oxygen transport through the oxygen transport channels established in the interfacial layer, resulting in the superior heat release and catalytic properties of [Quaternary]/μAl. The experimental results show that the nanoparticle interfacial layer reduces agglomeration between Al particles and greatly improves the heat release efficiency of Al powder. As a result, the exothermic decomposition peak of μAl increased by almost 400 °C. In addition, [Quaternary]/μAl exhibited excellent catalytic activity and stability for the thermal decomposition of an ammonium perchlorate/molecular perovskite energy material (AP/DAP-4), reducing the thermal decomposition temperature of AP/DAP-4 by approximately 80 °C and the activation energy to 228.1 kJ/mol. Combustion experiments revealed that [Quaternary]/μAl+AP/DAP-4 burned well, with the highest combustion pressure and boost rate and a flame temperature of 2002 °C. On the basis of these experimental phenomena and results, a mechanism for heat release and the catalytic thermal decomposition of [Quaternary]/μAl+AP/DAP-4 composite fuels is proposed. In conclusion, the improvement in the overall performance of metal fuel/oxidizer composites by the formation of interfacial layers through substitution reactions is expected to have a wider application in solid propellants.