Ignition of Mixed Powder of DAP-4 and Nano-Al Using Shock Tube

Al is widely used in solid propellants for its high energy density. (C 6 H 14 N 2 )[NH 4 (ClO 4 ) 3 ]（DAP-4）, a novel energetic material, exhibits excellent detonation performance, thermal stability, oxidizing capacity, and cost efficiency, making it a promising high-energy oxidizer. This study investigated the ignition and combustion properties of DAP-4/nano-Al mixtures. DAP-4 was synthesized via a one-pot molecular self-assembly strategy, and mixtures with varying Al ratios (10%–30%) were prepared through mechanical mixing. X-ray diffraction (XRD) confirmed that the mixed powders retained their original crystalline structures without the formation of new phases. Scanning electron microscopy (SEM) revealed that nano-Al particles adhered effectively to DAP-4 surfaces, with higher Al content increasing the particle coverage. Elemental mapping and EDS were used to further characterize the surface morphology changes. Thermogravimetry-Differential Scanning Calorimetry（TG–DSC） indicated good compatibility between DAP-4 and nano-Al, with minimal mutual interference during thermal decomposition. Ignition experiments were conducted in a shock tube under temperatures (2200–3100 K) and pressures (0.1 and 0.5 MPa). The results showed that in the DAP-4/nano-Al mixtures, an increase in the Al fraction caused a decrease in the ignition delay time and an increase in the burn time. Simultaneously, the reaction in the presence of Al changed qualitatively, as is apparent from the changed activation energies. Compared to the combustion of neat DAP-4, both the ignition delay and burn times could be longer or shorter, depending on the Al fraction. This study demonstrated that the addition of nano-Al effectively enhanced DAP-4 combustion. In practice, DAP-4's ignition and combustion can be controlled by adjusting the nano-Al mass fraction.