Efficient and synergistic preparation of HNS-based energetic composite microspheres by the continuous drop-ball method and optimization of their multi-dimensional performance

Abstract

This study presents an innovative continuous ball-dropping device combined with high-speed stirring and curing to successfully produce HNS-based energetic composite microspheres with uniform components and complete coatings. The effects of process parameters such as binder content, suspension concentration, continuous phase concentration, and stirring rate on the morphology and particle size distribution of the microspheres were systematically examined. The study further investigates the impact of the continuous ball-dropping method on fluidity, chemical structure, bulk density, thermal properties, mechanical sensitivity, and combustion properties of the microspheres. Results show that compared to Nano-HNS, the HNS-based microspheres prepared by the ball-dropping method exhibit improved fluidity (angle of repose: 37.97° vs 22.09°), higher bulk density (0.453 g·cm⁻³ vs 0.552 g·cm⁻³), and increased activation energy. Mechanical sensitivity tests show a significant safety improvement, with critical impact energy increasing from 2.5 J to 40 J and friction sensitivity rising from 108 N to 180 N. The combustion performance of microspheres prepared by this method exhibits a larger flame area and shorter combustion time, thereby improving energy release efficiency. Compression performance improves as well, with microspheres exhibiting increased compression resistance, rising from 14.04 MPa to 37.02 MPa compared to traditional methods. In conclusion, the continuous drop ball method, combined with high-speed stirring and curing, efficiently produces fully coated energetic composite microspheres, offering a promising route for the large-scale industrial production of energetic materials.