Investigation of Thermal Behavior of Micronized Ammonium Perchlorate Produced by Enhanced Anti-Solvent Crystallization Method

Ammonium perchlorate (AP) is considered as a strong oxidizer in solid propellants. Therefore, its thermal decomposition characteristics directly influence the combustion behavior of solid propellants. The AP particle size, shape, and morphology influence on the thermal behavior. In this study, the solvent anti-solvent crystallization method equipped with an eductor mixer was used as a system for producing oxidizing materials for propellants. The eductor easily increases the quality of mixing and does not cost much to launch and utilization. The crystallinity of produced ammonium perchlorate and reference samples were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD) methods. The results showed that the produced crystals in this system have a regular morphology and were crystallized in the form of an orthorhombic structure. On the other hand, the growth of the crystal in plane (011) of the produced samples is weakened compared with the reference sample and the growth in (210) plane is greater than the reference sample. Thermal behavior analysis by thermogravimetric analysis (TGA) showed that the produced sample has a one-step decomposition peak while in the reference sample, a two-stage peak is observed. Also, differential scanning calorimetric (DSC) illustrated that the produced fine AP samples in exothermic decomposition has an intermediate peak. This peak has a high overlay with low temperature decomposition (LTD) and high temperature decomposition (HTD) peak. In general, decomposition of produced sample showed one exothermic peaks.