Compatibility of nitroguanidine with seven high explosives determined by gas generation and heat flow microcalorimetry

Two compatibility tests based on gas generation obtained by Vacuum Stability Test (VST) procedure and on heat generation obtained by Heat Flow MicroCalorimeter (HFMC, often called just HFC)) were conducted in accordance in experimental methods and in assessment with NATO STANAG 4147 (only VST) and NATO AOP-41471 (VST and HFMC). The evaluation method was our own one, it is congruent with AOP-4147. The used assessment quantities were the so-called reactivities RV with gas generation (GG) and RQ with heat generation (HG), for which certain limit values apply. The obtained reactivity values for 1:1 mixtures per mass pro-vided with the results that nitroguanidine (NGu or Nigu) is compatible with ammonium nitrate (AN), ammonium dinitramide (ADN), N-guanylurea dinitramide (FOX-12, GUDN, carbamoylguanidinium dinitramide (CGDN)), 1,1-diamino-dinitroethylene (FOX-7, DADNE), hexogen (RDX), octogen (HMX), and trinitrotoluene (TNT). NGu and ADN show the rare case of reactivity with a negative assessment quantity, means their inter-component reactivity quantities show negative values in RV and RQ. This means the evolved gas volume and the produced heat generation of the 1:1 mixture have lower values than the formally calculated values of the mixture. The reactions behind this feature cannot be deduced with the mere compatibility testing. A negative assessment quantity RQ is shown also between NGu and TNT at 80°C, but not at 70°C.