基于相变材料包覆的高渐增性发射药制备及性能OA

In response to the higher demands for progressive combustion and reduced erosion in small and medium-caliber rapid-fire weapons,a coating system based on stearic acid/silica/polyurethane(SA/SiO2/PU)phase change material was de-signed,and the oblate-gun propellants were prepared by combining with fluidized bed technology.The compatibility,thermal decomposition,microstructure,combustion performance and storage stability of the propellants were investigated using differen-tial scanning calorimetry,Raman spectroscopy,scanning electron microscopy,and a closed bomb.Results indicate that the SA/SiO2/PU coating system exhibits Grade 1 compatibility with the propellant.The enthalpy of melting(ΔHm)and crystallization(ΔHc)of the coating system are 39.02 J·g-1 and 39.46 J·g-1,respectively,indicating a reversible phase transition process and good chemical stability.Microstructural analysis reveals that the propellant surface is densely and uniformly coated,with a coat-ing thickness of approximately 13 μm under the coating time of 20 min.Compared with the uncoated propellant,the initial dy-namic vivacity(L0)and maximum dynamic vivacity(Lm)of the coated propellants decrease by respectively 48.0%and 44.7%,while the dynamic vivacity difference(ΔL)increases to 0.22 MPa-1·s-1,demonstrating high progressive combustion characteris-tics.In terms of storage stability,the average gas evolution of the coated propellant is 1.04 mL·g-1,and the methyl violet test shows a 6.25%extension in discoloration time,suggesting that the coating process contributes to an improved storage stability of the oblate-gun propellant.