Phase transformations of 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane: the role played by water, dislocations, and density

Abstract

A comparative study of the kinetics and mechanisms of the α → γ and ɛ → γ polymorphic transitions in polycrystalline haxanitrohexaazaisowurtzitane was performed using electron and optical microscopy, calorimetry, IR spectroscopy, and quantitative X-ray phase analysis. The kinetics of both processes is complex because of the morphology of the crystals, their defect structure, and impurities. As distinct from the ɛ → γ process, which always occurs as a single crystal-polycrystal transition (through nucleation by the dislocation mechanism with subsequent movement of the phase separation front), the α → γ process can also follow the quasi-homogeneous mechanism and occur as a single crystal-single crystal transition.