包覆微孔球扁药的结构与性能

Structure and Properties of Coated Microporous Oblate Spherical Propellant

球扁药是中小口径和轻武器的主要装药,其能量释放渐增性的控制方法一直是研究的热点。通过超临界二氧化碳微发泡的内部微孔增燃与流化床包覆的表面包覆阻燃相耦合,构筑了能量释放精准可控的乙基纤维素(EC)包覆微孔球扁药,利用扫描电镜和红外光谱研究其微观结构与组成,采用密闭爆发器等分析其燃烧和贮存性能。结果表明:包覆微孔球扁药表面结构完整、致密,当包覆时间从5 min增加到30 min时,包覆层的质量分数从2.32%增加到9.79%,对应的膜厚从7μm增加到33μm;相比于原药,包覆时间10 min的包覆微孔球扁药,其初始活度L_(0)和最大活度L_(m)分别降低了62.34%和55.61%,燃烧渐增性特征值A_(L-B)为1.30 MPa^(-1)·s^(-1);加速老化试验表明,包覆微孔球扁药的燃烧性能变化较小,在75℃老化14 d后,老化样品与未处理的原始样品的p‑t和L‑B曲线基本保持一致,表明EC包覆微孔球扁药具有优异的贮存稳定性。

Oblate spherical propellant is the main charges for small and medium caliber and light weapons,and the method of controlling its progressive properties has consistently been a hot research topic.The ethyl cellulose(EC)-coated microporous gun propellant was developed by combining internal microporous combustion enhancement using SC-CO2 and the surface coating flame retardant via fluidized bed coating,resulting in precise and controllable energy release.Scanning electron microscopy and infrared spectroscopy were applied to investigate the microstructure and composition,and the closed bomb device was used to analyze the combustion and storage performance.The results showed that the coated microporous gun propellant exhibited surface structural integrity and density.The mass fraction of the coating layer increased from 2.32%to 9.79%when the coating time was increased from 5 min to 30 min,and the corresponding film thickness increased from 7μm to 33μm.Compared with the original gun propellant,the initial and maximum activities L_(0) and L_(m) of the microporous gun propellant with 10 min coating time were reduced by 62.34%and 55.61%,respectively,with an A_(L-B) characteristic value of 1.304 MPa^(-1)·s^(-1).Accelerated aging tests showed minimal changes in the combustion performance of the coated spherical propellant.The p‑t and L‑B curves of the aged samples were consistent with those of the untreated samples after aging at 75℃for 14 days.This indicated that the EC-coated microporous gun propellant exhibits excellent storage stability.