Sensitivity and performance of HMX coated with SiO₂

In order to prepare the insensitive explosive with high energy density in initiators and pyrotechnics, based on sol-gel method, the solution of dimethyl sulfoxide(DMSO) dissolving Octagon(HMX) with definite concentration was added into sol-gel system at gel point, and then the composite crystalline HMX/SiO₂(90/10) was prepared by the phase transformation process of silica(SiO₂). The composite structure was characterized by scanning electron microscopy(SEM) and Fourier Transform Infrared Spectroscopy (FT-IR). SEM images indicate that HMX/SiO₂ aerogel is approximate to a sphere with 0.5~1 μm diameter. The tests of mechanical sensitivity show that the critical height H50 (12Tool, 2.5 kg drop hammer) rises from 18.70 cm to 32.24 cm, and the explosion percentage of friction falls from 100% to 20%. The thermal stability was also evaluated using thermogravimetry and mass spectrometry. The detonation velocity was also measured. The result shows that the performance of booster is mainly affected by the charge uniformity of small-scale pipe. Specially, the critical booster diameter was 0.6 mm at the average density of 1.15 g/cm³ and restrained by copper pipe, and then the corresponding detonation velocity was 5 320 m/s.