Condensed-Phase Processes During Solid Propellant Combustion. V. FurtherObservations on Depth Profiling of Burned Surfaces of XM39 and M43 Propellants

摘要

Samples of XM39 and M43 propellants that have been self-extinguished at lowpressures have been examined under a Scanning Electron Microscope (SEM). The results of this examination suggest that the surface layers of burning HMX/RDX propellants consist of a thin, smooth layer presumably made up of binder and its decomposition products. This layer overlies a thicker layer of crystalline, bubble-containing material that is presumably mostly solidified or recrystallized (liquified during combustion) RDX oxidizer. Photoacoustic Fourier Transform Infrared (FTIR) spectra of some burned/extinguished samples of XM39, JA2, and RDX are also reported and discussed. Based on our results to date, presented in this and previous reports, some suggestions for modelers of nitramine propellant combustion are presented. It is suggested that, if practicable, formation and subsequent decomposition of nitrosoamines, such as MRDX and DRDX, should be included in the condensed-phase chemistry models of deflagration of RDX and of RDX-based propellants. Also, the mathematical framework should include provision for formation and growth of bubbles in the liquid layer as a result of both thermal decomposition and vaporization of RDX.