Properties and Structure of ADN-Prills

Ammonium dinitramide (ADN) is the upcoming oxidizer for solid propellants of the current decade. Spherical ADN particles, so‐called ADN‐prills, are a key product for the development of environmentally friendly and low‐signature solid propellants for defence and space applications. At the moment the particle size and the spherical shape of the ADN‐prills can be controlled by the emulsion crystallization process or by spray congealing processes. In this work the crystal structure and the thermal‐ and mechanical stability of ADN‐prills were investigated. By temperature resolved X‐ray diffraction measurements new insights about temperature depending crystalline structures inside of ADN‐prills could be gained. Anisotropic crystal properties could be detected at certain temperature ranges between ambient temperature and the melting point of ADN at 93 °C. Due to the unexpected material properties of molten ADN droplets a surprising correlation between process parameters, particle size, crystal structure, thermal stability and mechanical stability was found. This leads to a more profound knowledge about the crystal structure of ADN‐prills and gives the opportunity to produce enhanced ADN particles for propellant applications.