Multilayer coating of spherical gun propellants via fluidized bed techniques: Enhanced combustion performance and storage stability

To address key challenges of conventional spherical gun propellants, including inconsistent energy release, harmful gas emissions, and long-term storage instability, this study utilizes fluidized bed technology combined with composite energetic coating systems to prepare multilayer-coated spherical gun propellants. The coated propellants were systematically characterized using scanning electron microscopy (SEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and dynamic vapor sorption (DVS) analysis to investigate their microscopic morphology, chemical structure, and moisture uptake characteristics. The results indicate that the coating forms a tight bond with the propellant substrate while establishing a distinct energy gradient, exhibiting excellent water resistance and enhanced stability. Closed bomb tests and accelerated aging tests further revealed that the multilayer coating effectively modulates progressive burning characteristics and provides superior aging resistance. This work presents a novel approach for developing multifunctional small-size gun propellants.