Anti-hygroscopicity technologies for ammonium dinitramide: A review

Valuable propellants have the characteristics of high impulse, low pollution, and strong stability, and oxidizers play a substantial role in determining the performance of propellants. Ammonium dinitramide (ADN) is a relatively promising oxidizer due to its high-energy and chlorine-free characteristics. However, although ADN exhibits high energy performance compared with traditional oxidizers, the high hygroscopicity of ADN when exposed to high humidity restricts its broader application in solid propellants. This review highlights the necessity of utilizing anti-hygroscopicity strategies with ADN to extend its application. The anti-hygroscopicity mechanism of ADN is summarized by calculations and experimental results. Anti-hygroscopicity technologies that can be used with ADN include prilling, surface coating, and co-crystallization, and these technologies are comprehensively summarized herein. This review is intended to provide insight into the use of anti-hygroscopicity technologies with ADN, highlight the challenges of these methods, and point out future development directions.