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Thermal expansion, transitions, sensitivities and burning rates of HMX
Author(s) -
Herrmann Michael,
Engel Walter,
Eisenreich Norbert
Publication year - 1992
Publication title -
propellants, explosives, pyrotechnics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.56
H-Index - 65
eISSN - 1521-4087
pISSN - 0721-3115
DOI - 10.1002/prep.19920170409
Subject(s) - thermal expansion , diffraction , thermal decomposition , phase transition , decomposition , materials science , volume (thermodynamics) , thermal , powder diffraction , thermodynamics , thermal analysis , analytical chemistry (journal) , chemistry , crystallography , composite material , organic chemistry , optics , physics
The phases of HMX and their transitions were investigated by thermal analysis using X‐ray diffraction. Series of diffraction pattern were measured, while the samples were heated and cooled. The thermal expansion coefficients and the colume changes at the transitions were extracted from the diffraction series. A contraction of β‐HMX was found before changing into δ‐HMX resulting in a high volume difference during the transition. On cooling, the reconversion of the high temperature phase requires days. It is further slowed down by decomposition products, which are formed at temperatures beyond 490 K. The final reconversion results in mixtures of α‐and βHMX. The mechanical sensitivities and the buring rates of the HMX phase were determined. The high sensitivity of δ‐HMX against impact together with its slow reconversion creates handling risks when the HMX is exposed to temperatures above 440 K.