Low-temperature structural deformation and fragmentation of lead styphnate by in-situ experiments and calculation

As one of the most used pyrotechnic composites in spacecraft pyrotechnic devices, the reliability of lead styphnate (LS) in a cryogenic environment needs an adaptability evaluation before the deployment of new deep space exploration programs. Nonetheless, there is a limited understanding of the effects of low temperatures on LS. Herein, we have designed cryogenic storage experiments with a low-temperature in-situ methodology to explore the effects of low temperatures on the properties and performance of LS. By comparing the experimental data before, after storage, and at low temperatures, LS exhibited unique characteristics and failure behaviors at low temperatures than at high temperatures. After storage, the impact sensitivity of LS increased sharply due to particle fragmentation, whilst the flame sensitivity of LS decreased significantly at low temperatures. Employing in-situ powder x-ray diffraction (PXRD) characterization and ignition tests, the low-temperature ignition failure of LS is thought to be closely related to the distortion of the crystal structure of LS, resulting in a “structural shutdown” at −80 °C. Our study disclosed the properties of LS at low temperatures and provided feasible research methods for other energetic materials, aiming to prevent possible future risks and help to establish test standards at low temperatures.