Anti‐hygroscopicity technologies for ammonium dinitramide: A review**

Abstract

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.

Surface denitration structure on dynamic combustion performance and muzzle flame of mixed nitrate gun propellant

“…The denitration degree of gun propellant was represented by the loss of explosion heat (Q v ), as shown in The electrostatic, impact and frictional sensitivities reflect the safety of the gun propellant in different scenarios and stimulations [36,37]. Figure 3(g) shows these three types of sensitivities of the samples with different denitration degrees or without denitration treat.…”

“…Assuming the gun propellant contained only NC, NG, TEGDN and C2 without other substances, the theoretical average nitrogen content of the NC in the gun propellant was reversely calculated as shown in Figure 3(f) according to the NG, TEGDN and C2 contents and the explosion heat results. With the increasing denitration time, the theoretical average nitrogen content of the NC decreased gradually, which confirms the involvement of NC in the denitration reaction.The electrostatic, impact and frictional sensitivities reflect the safety of the gun propellant in different scenarios and stimulations[36,37]. Figure3(g) shows these three types of sensitivities of the samples with different denitration degrees or without denitration treat.…”

Research progress on the catalytic and thermal decomposition of ammonium dinitramide (ADN)

“…Therefore, it is necessary to prevent the deterioration of ADN during its storage process. 28,29 Solid propellants do not require a complex fuel supply and combustion control systems, which makes solid thrust systems more reliable. 23 As a result, ADN can also be used as an oxidizer and mixed with fuels, binders, and plasticizers to prepare solid composite propellants, which makes it promising to replace the traditional oxidant AP.…”

Modulation of ADN Crystal Surface Properties by Additives

“…3,4 However, the strong hygroscopicity of ADN prevents its widespread application. Some studies have shown that, under a relative humidity of more than 50%, ADN crystals will be deliquescent within 10 h. 5 Thus, to fully utilize ADN as a green and energetic oxidizer, strategies for improving the antihygroscopicity properties of ADN have been widely researched. Currently, methods for reducing the hygroscopicity of ADN include spheroidization, 6,7 coating, 8,9 and cocrystallization.…”