One-Step Synthesis AlCo2O4 and Derived “Al” to Double Optimise the Thermal Decomposition Kinetics and Enthalpy of Ammonium Perchlorate

The solution combustion method is widely used because of its simple operation and ability to produce porous structures. The chemical composition and morphological structure of the material can be regulated by different oxidiser-to-fuel ratios (φ). In this work, AlCo2O4 derived “Al” catalytic materials were successfully synthesised by adjusting the fuel-to-oxidiser ratio using a one-step solution combustion method. On the one hand, the aluminium nanoparticles act as a part of the metal fuel in the composite solid propellant and, at the same time, serve as a catalytic material. In contrast, the thermal decomposition performance of AP was significantly improved by the synergistic catalysis of AlCo2O4. Among the samples prepared under different fuel ratios, considering all aspects (high-temperature decomposition temperature, activation energy, and decomposition heat) comprehensively, the AlCo2O4 prepared with φ = 0.5 had a more excellent catalytic effect on AP thermal decomposition, and the THTD of AP was reduced to 285.4 °C, which is 188.08 °C lower. The activation energy of the thermal decomposition of AP was also significantly reduced (from 296.14 kJ/mol to 211.67 kJ/mol). In addition, the ignition delay time of AlCo2O4-AP/HTPB was drastically shortened to 9 ms from 28 ms after the addition of 7% AlCo2O4 derived “Al” catalytic materials. Composite solid propellants have shown great potential for application.