Preparation of hydroxylammonium pentazolate composite microspheres with effective anti-hygroscopicity and their safety

Hydroxylammonium pentazolate (NH 3 OHN 5 ) is regarded as a novel energetic material with outstanding performance, yet its practical application has been hindered by significant hygroscopicity and high sensitivity. To address these challenges, this study prepared a series of NH 3 OHN 5 -based energetic composite microspheres using a combined solution-suspension method and copper-alginate (CA) gel network strategy. Experimental results demonstrated that the composite microspheres maintained well-defined morphology and preserved the original crystal structure, while exhibiting significantly reduced hygroscopicity and mechanical sensitivity, with a minimum energy loss of only 2.30%. Among the suspension-coated samples, the fluororubber (F 2603 )-coated sample (F-QA) exhibited the optimal comprehensive performance, which is attributed to the superior chemical inertness and hydrophobicity of fluororubber. This translated to a 9.48% reduction in hygroscopicity and an impact sensitivity of 40 J. Among all samples, the copper alginate-coated sample (SA-3) demonstrated superior overall performance. It exhibited a uniform and well-defined spherical morphology, with a 14.28% reduction in hygroscopicity compared to the raw NH 3 OHN 5 at 25 °C and 70% relative humidity ( RH ). Additionally, its impact sensitivity (16 J) improved by 11 J compared to the raw NH 3 OHN 5 (5 J), while the friction sensitivity (144 N) rose by 102 N relative to the raw NH 3 OHN 5 (42 N). This work demonstrated that F 2603 and copper alginate are effective coating materials, providing excellent anti-hygroscopicity and reduced impact sensitivity, which promoted the application of NH 3 OHN 5 as a novel explosive in the field of energetic materials. A series of NH 3 OHN 5 -based energetic composite microspheres was prepared by a combined solution-suspension method and a copper-alginate (CA) gel network strategy. • Multiple hydroxylammonium pentazolate (NH 3 OHN 5 )-based composite energetic microspheres were successfully fabricated via a suspension coating method and copper alginate (CA) gel network. • The composite microspheres demonstrate reduced mechanical sensitivity and hygroscopicity, thereby achieving effective improvements in the safety and storage stability of NH 3 OHN 5 . • This study develops a versatile coating strategy that can be extended to other pentazolate-based energetic systems to facilitate performance optimization.