Fabricating a Flexible Binary Black Powder Aerogel with a High Sensitivity Threshold via the In Situ Growth of KNO₃...

Due to the lack of the binding effect from sulfur, binary black powder exhibits highly intrinsic brittleness, thereby severely restricting its processability and uses. In this paper, based on agar-induced growth of KNO₃ submicron fibers, a binary black powder aerogel was prepared by the freeze-drying of suspensions, in which KNO₃ submicron fibers were recrystallized in situ along with carbon fibers. The maximum porosity of the aerogel is 99%, with an apparent density of 0.02 g·cm^-3, a compressive modulus of 1.87 MPa, and a deformation rate of up to 95%, which give it excellent, ultra-flexible, and ultra-light properties. Furthermore, its mechanical and electrostatic sensitivity thresholds both exceed the detection limits of the test instruments, which means it is extremely insensitive. The findings of the paper can significantly improve the poor processability of traditional black powder, increase its potential applications, and lay a technical foundation for revitalizing its use. In addition, the exceptionally high mechanical and electrostatic sensitivity thresholds of binary black powder aerogel may provide a new way to improve black powder's safety.