Multi-person assessment of RDX crystal morphology using the RS-RDX round robin method

摘要

The crystal morphology of cyclotrimethylenetrinitramine (RDX) has been linked to the shock sensitivity of polymer bonded explosives. During the reduced sensitivity RDX Round Robin (R4) study, crystal morphology was assessed using contrasting fluid optical microscopy and a scoring system. This method was able to show a difference between different crystal lots. However the method was very subjective and large variations between assessments were seen. The procedure was repeated by the author, a larger number of crystals from each batch were examined. Similar results were obtained compared to the R4. To gain a better understanding of how subjective/variable the method is, micrographs were assessed by a larger number of (unskilled) analysts and the results compared. The results showed reasonable agreement between assessors. Unprocessed type B RDX lots were on average assessed to be more angular, but also had the most variation between assessors. There was closer agreement between type A RDX lots which were assessed to be smoother. The method was found to be time consuming by many of the assessors.