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Fragmentation of Ammonium Nitrate Particles under Thermal Cycling
Author(s) -
Maggi Filippo,
Garg Priya
Publication year - 2018
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.201700230
Subject(s) - ammonium nitrate , propellant , ammonium , fragmentation (computing) , explosive material , nitrate , particle size , chemistry , chlorine , materials science , thermal , temperature cycling , chemical engineering , metallurgy , thermodynamics , organic chemistry , physics , computer science , operating system , engineering
Abstract Ammonium nitrate finds application in explosives and chlorine‐free slow‐burning propellants. Different phases are known for this ammonium salt, each of them featured by peculiar bulk densities. As a consequence, the variation of storage temperature induces processes of expansion‐contraction in the crystals, unless specific stabilization is performed. In this paper, a batch of raw ammonium nitrate particles has been thermally cycled between −30 °C to +60 °C and analyzed. Microscopic observations, particle size measurement, and X‐ray microtomography showed that the particles undergo a progressive fragmentation process, with opening of internal cracks and voids. The tested material halved its mass‐mean diameter after five thermal cycles. As a term of comparison, a phase‐stabilized ammonium nitrate batch was tested under the same conditions, showing no effect.