Preparation and Characterization of Nanostructured Composition B

Explosive compositions employing nanoscale crystals of high explosives (HEs) have demonstrated reduced sensitivities to external stimuli. Up to date, the investigated compositions are limited to plastic bonded explosives (PBX). It is also desirable to use nanoscale HEs in explosives that are conventionally produced by melt cast to address their sensitivity issues. However, the integration of nanoscale HEs into the melt cast process is challenging due to their high surface area. In this work, we explored the preparation of nanoscale HEs based Composition B (Comp B), a widely used high performance explosive commonly prepared by melt cast process, by spray drying and sequential pressed formulation. The composite particles obtained after spray drying were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). The particles were also tested in impact, friction, and electrostatic discharge tests before pressed formulation. The formulated Comp B explosive was analyzed using focused ion beam- (FIB-) SEM, illustrating a novel nanostructure characterized by a large amount but small voids (~ 200 nm). The nanoscale HEs based Comp B demonstrated improved shock sensitivity in small scale gap test (SSGT). This work is consistent with previous observations that the use of nanoscale HEs can reduce the shock sensitivity of explosives. It also opens an avenue for producing nanoscale HEs based compositions unachievable using the conventional melt cast formulation process.