Recent advances on the crystallization engineering of energetic materials

doi:10.1016/j.enmf.2020.12.004

Energetic Materials Frontiers

Volume 1, Issues 3–4, December 2020, Pages 141-156

https://doi.org/10.1016/j.enmf.2020.12.004 Get rights and content

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Highlights

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The crystal quality such as particle size, crystal surface morphology and crystal internal defects can be improved through various crystallization process.
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The EMs crystals with lower sensitivity, higher thermal stability and better energy performance can be obtained by crystallization.
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The crystalline EMs properties like crystal morphology and particle size can be altered by crystallization process to meet different needs.

Abstract

The safety properties and desirable detonation performance of energetic materials (EMs) are mutually exclusive, therefore, various strategies including the coating, doping, crystallization, and co-crystallization, are applied to achieve high-energy insensitive explosives with well-balanced energy and safety level. Among these strategies, the crystallization is the most commonly method owing to its low cost and facile process, through which the tuning of the particle size and morphology, adjust sensitivity of EMs by tailoring the processes conditions. As the control of the crystal particle size is difficult, the ultrasound and electrospray are introduced, and by use of the spray drying or spray-assisted electrospray methods, the spherical RDX, HMX, and CL-20 crystals with less defects is obtained. Moreover, the perfect spherical crystals are gained without agglomeration through employing polymeric additives in the crystallization process. In general, the crystallization with spray drying, electrospray, and ultrasound-assisted solvent/antisolvent are the optimal crystals preparation methods. The nano-crystals with narrow particle size distribution are less sensitive to external stimuli than irregular microcrystals, and defects are associated with hot spots, the safety and energy performance of EMs could be well balanced by crystallization.

Graphical abstract

The crystalline energetic material (EMs) with desired physical and chemical properties could be prepared by various crystallization methods. Crystallization is a promising strategy to balance the energy and safety of energetic crystals, whose morphology and crystal structure can be adjusted by tuning the crystallization conditions. Most importantly, crystallization engineering leads to a significant decrease in the crystal defects and impurities, which is reflected in reducing the probability of hot spot formation under external stimuli, thereby improving the thermal stability and sensitivity.

Keywords

Crystallization engineering

Crystal morphology

Crystal defects

Thermal stability

Explosive sensitivity

Cited by (0)

Xue-Xue Zhang is a master student in the academic committee of the national Key Laboratory on Combustion and Explosion, Northwestern Polytechnical University (NPU). She mainly focuses on the functional materials which can improve the combustion performance of solid propellants. In addition, she is doing researches on reducing the sensitivity of energetic oxidizer and turning the combustion performance of solid propellants. She has published 3 papers as the first author.

Qi-Long Yan is a Full Professor in the Northwestern Polytechnical University (NPU). He is a member of the academic committee of the national Key Laboratory on Combustion and Explosion, focusing his research on preparation, characterization, and reactivity of nanocomposite energetic materials. Before joining in NPU, he was a Postdoctoral Fellow at the Center of Nanoscience and Nanotechnology, Tel Aviv University (Israel). He obtained his Ph.D. in 2015 from the University of Pardubice (Czech Republic). He is currently serving as an adjunct professor for Institution of chemical materials, CAEP (China). He is also on the editorial boards of several journals including Chin J Propellants Explos, Energetic Mater Frontier and Chin J Energet Mater. He is authored with over 120 papers, two books, and 11 patents.