Preparation of HNS-based sticks through 3D printing and its combustion performance

Microscale energetic materials have garnered considerable attention because they can be integrated in microelectromechanical systems for several potential applications. Hexanitrostilbene (HNS) has been widely utilized in ignition and initiation devices owing to its excellent thermal and shock stability and high sensitivity to short pulse shock waves. To meet the energy release requirements of micro-detonation devices, HNS sticks were prepared using direct ink writing and their reaction and flame propagation properties were studied. HNS particles sized 17.5 µm to 5 µm and ∼500 nm was prepared. Then, the viscosity of HNS-based inks prepared via acoustic resonance technology decreased when the particle size decreased or when the HNS content reduced from 97 wt.%, 95 wt.%, and 92 wt.%, to 90 wt.%. Additionally, the HNS-based inks with different binders exhibited different viscosity. The effect of the inner diameter of needle (0.4 mm, 0.6 mm, and 0.9 mm), printing rate (13 mm/s, 15 mm/s, 17 mm/s, 19 mm/s), and pressure (0.05 MPa, 0.1 MPa, 0.15 MPa, 0.2 MPa) on the width of HNS sticks was also elucidated. HNS-based sticks with a diameter of 0.9 mm underwent self-sustaining combustion reactions, and the burning rate increased from 5.1 mm/s to 6.8 mm/s as the particle size decreased from 17.5 µm to 500 nm. Overall, this work provides an effective approach to prepare microscale HNS for integration into micro-energetic devices.