Links between the Morphology of RDX Crystals and their Shock Sensitivity

Abstract

It has been known for some time that batches of the secondary explosive RDX from different manufacturers show significant variation in their shock sensitivity. No clear correlation between shock sensitivity and either chemical composition or morphology has been identified. As yet no comprehensive study has been reported covering RDX from different manufacturers, different production methods, and different particle sizes. In this work we use a range of techniques to study the morphology of RDX grains more closely and to assess which hotspot mechanisms might be dominant. Crystals were characterised using mercury porosimetry, environmental scanning electron microscopy (ESEM) and optical microscopy. This range of methods yields quantitative data on internal void size and number and surface porosity. Shock sensitivity is quantified using small‐scale gap tests and these demonstrate clear differences in sensitivity between batches from different manufacturers. The samples used are from three manufacturers, produced by both the Woolwich and Bachmann processes, and of two different sizes, so a comprehensive study of how morphology might affect hotspot formation is possible.