Untersuchung des Phasenverhaltens von Ammoniumnitrat mit temperaturaufgelöster Röntgenbeugung und Rietveld-Analyse

Ammonium nitrate was investigated with temperature resolved X-ray diffraction. The measurements were evaluated by Rietveld analysis, an advanced crystallographic tool for powder diffraction patterns. The method yields lattice parameters and atom positions as well as intra- and intermolecular distances. Ammonium nitrate was heated and cooled stepwise in a temperature range between minus 60 and 140 deg. C, measuring an X-ray pattern after each temperature step. The results of the Rietveldanalysis were plotted versus temperature. The object of this work is to create an advanced basis for elucidating the phase stabilization mechanism caused by various additives. The overall target is a successful application of ammonium nitrate in propellants and explosives reached by tailoring its phase behavior.