Preparation of Combined Ammonium Perchlorate/Ammonium Nitrate Samples by Freeze Drying

Ammonium perchlorate (AP) and ammonium nitrate (AN) are used as propellant oxidizers. In this study, the preparation of combined AP/AN particles by a freeze-drying technique was attempted to improve the burning characteristics and determine the combustion wave mechanism of composite propellants. AN adhered to AP particles during the drying process to form combined AP/AN particles. Some freeze-dried sample adhered to the inside surface of the vessel. The nonadhered sample precipitated at the bottom of the vessel. It was found that the AN content of the combined AP/AN samples dominated particle properties, including shape, hygroscopicity, thermal decomposition behavior, and ignition sensitivity.