【作者】 闫石；

【导师】 成一；

【作者基本信息】 南京理工大学 ， 军事化学与烟火技术， 2013， 博士

【摘要】 含能材料的能量水平是武器系统性能的关键技术之一。将微米、纳米(微纳)的铝或硼等加入到含能材料中可以提高含能材料的能量水平和燃速。但是,微纳铝、硼在含能材料加工中不易分散均匀；其次,微纳铝、硼在制备、储存、使用的过程中容易钝化,活性降低。本文创新性的采用高压静电纺丝和静电喷雾的方法,制备了复合含能材料的亚微米纤维和微米球形颗粒,从而提高它们在含能材料中的分散性,增加了燃速。针对微纳颗粒在自然贮存过程中容易钝化的问题,采用热分析TG-DSC(Thermogravimetry-Differential Scanning Calorimetry)方法研究了微纳硼的氧化反应机理。采用溶剂提纯法和湿法球磨法对老化的微纳硼进行活化,提高了硼延期药的燃速。首次采用静电纺丝法制备了直径为几百纳米、长度大于500μm的NC(硝化棉)/Al-CuO和NC/Al-Cu(NO3)2含能纤维。对含能纤维的SEM、TEM、EDS等实验表明：纳米Al、Al-CuO、Al-Cu(NO3)2颗粒可以均匀地分散在纤维的内部。采用高速摄影法测试了含能纤维的燃烧性能,研究发现：NC、NC/Al、NC/Al-CuO的燃烧较完全,而NC/Al-Cu(NO3)2的燃烧不完全；NC的燃速为12.4cm/s,NC/Al的燃速小于NC的燃速,且随着铝含量的增加,燃速下降；Al-CuO含量为50%的NC/Al-CuO纤维织物的燃速为106cm/s,比纯NC纤维的燃速提高了8.5倍。首次采用高压静电喷雾法制备了直径为几微米到几十微米的Al-CuO/NC复合颗粒。研究发现：当NC含量为10%时,Al-CuO/NC复合颗粒的形貌最规整,粒径分布较窄；纳米Al、CuO和NC在复合颗粒中均匀分散；当NC含量为1%-10%时,Al-CuO/NC复合颗粒中的孔隙逐渐减少,复合颗粒变得密实；当NC含量为13%,复合颗粒之间出现纤维。采用燃烧压力微元测试了团聚颗粒的燃烧性能。研究发现,NC含量为3%的样品具有最大的燃烧压力增长速率和最大的光强度,当NC含量大于3%,随着NC含量增加,样品的燃烧反应减弱。采用热分析TG-DSC方法研究了微纳硼的氧化反应机理。结果表明：(1)硼的氧化反应分为快反应和慢反应两个阶段。(2)采用Ozawa法计算了微纳硼快反应的动力学参量,采用非线性拟合技术研究了快反应的最佳反应机理,微纳硼的快反应为一阶反应。(3)经过自然贮存3个月的纳米硼的有效含量下降了6.6%,氧化反应初始温度和峰温都提高了30℃以上；自然贮存10年的微米硼的有效含量下降了66.7%,氧化反应初始温度和峰温都提高了20℃C以上。采用溶剂提纯法和湿法球磨法对老化的微纳硼进行了活化处理,并采用TG-DSC研究了活化效果。研究发现,溶剂提纯法对老化纳米硼没有明显的活化作用,但是可以将老化微米硼的有效含量提高一倍左右。湿法球磨采用无水乙醇和NaOH作混合液,可以明显提高老化纳米硼的反应活性,氧化反应初始温度和峰温降低了约20℃。研究了微米硼/四氧化三铅(Pb3O4)和微纳硼/铬酸钡(BaCrO4)延期药的燃速和反应机理,采用光-电靶法测试了延期药的燃速。研究发现：(1)B/Pb3O4延期药的燃速与硼含量成线性关系,活化硼延期药的燃速是老化硼延期药燃速的2.2倍左右；(2)在B/BaCrO4延期药中纳米硼延期药的燃速大于微米硼延期药的燃速,活化硼延期药燃速大于老化硼延期药的燃速。更多还原

【Abstract】 A key point to enhance the performance of weapon systems is to increase the energy density of the energetic materials used in the weapons. The addition of micron-sized and nano-sized boron and aluminum to energetic materials can really achieve a higher energy release and bigger burn rate in certain experiment conditions. However, when the loading of nano particles becomes higher during the preparation of castable energetic materials, the viscosity of the solution will become very large, cause the deterioration of the procedure. Besides, nanoaluminum and nanoboron are very easily to be oxidized during the production, storage and usage, the oxide layer formed on the surface of the particle caused reduce of the chemical reactivity and the effective contents. An investigation of making nanoparitcles into sub-micron fibers and micron spherical particles by electrospinning and electrospray is introduced here, trying to solve the problem of the aggregation of nano particles.The nano particles are aimed to be made to larger sized agglomerations without reducing its reactivity. The oxidation kinetics of boron was investigated by TG-DSC. The aging process of boron during natural storage was also studied by TG-DSC. For the aging boron, solvent washing and mechanically milling were taken for its purification. TG-DSC was used to study the effect of the treatment. Combustion properties of the boron delay composition were also studied with the treated boron.Electrospinning technique was used to make NC(nitrocellulose)/Al-CuO and NC/Al-Cu(NO3)2fibers with the diameter of several hurdred nanometers and a length of more than500μm. Al, CuO and Cu(NO3)2were homogenously dispersed in the fibers. High speed camera was used for the measurement of the burn rates of NC, NC/Al, NC/Al-CuO and NC/Al-Cu(NO3)2fibrous textiles in the open air. Results show that the combustion of NC, NC/Al and NC/Al-CuO fibrous textiles were completely finished. However, a lot of solid residues were generated during the combustion of NC/Al-Cu(NO3)2. The burn rate of NC was12.4cm/s, the burn rates of NC/Al were even smaller than NC. With the increase of Al in the NC/Al, the burn rate decreased. NC/Al-CuO containing50%Al-CuO had the biggest burn rate (106cm/s), which was8.5times of pure NC fibers.Micron-sized Al-CuO composites were firstly electrosprayed. The Al-CuO/NC with10%NC had the best morphology. There were vacancies between nanoparticles in the big particles. With the increase of NC, the as sprayed particles became close-grained. The nano Al and CuO particles were homogenously dispersed in the bigger particles. When the content of NC was 13%, fibers were seen between big particles. Burning pressure cell tests were taken to investigate the combustion properties of the aggregated spherical particles. Results show that AI-CuO/NC with3%NC had the biggest burn rate and optical strength. When the content of NC was bigger than3%, the combustion of Al-CuO/NC became weaker.Thermoanalytical techniques TG-DSC were introduced to investigate the oxidation kinetics of nano boron and micron boron. Results show that:(1) The oxidation of boron consisted of two steps, called fast reaction and slow reaction.(2) Ozawa equation was used to calculate the kinetics parameters of the fast reaction, and non-linear coefficient was used to get the optimum oxidation mechanism. Results show that the oxidation of boron was F1.(3) Nano boron lost6.6%of its active content during3months of natural storage, the onset temperature and the peak temperature of the reaction was30℃higher than before; while micron boron lost66.7%of its active content during10years of natural storage, the onset temperature and the peak temperature of the reaction was20℃higher than before.Solvent washing and mechanically milling were taken to purify the aging nano and micron boron, TG-DSC was used to study the effects of the treatment. Results show that there was no obvious improvement by the solvent washing for nano boron. But the active content of micron boron could increase by100%with solvent washing. Mechanically milling was taken with absolute ethanol as solvent to protect boron from being oxidized. Sodium hydroxide (NaOH) was added to the mill. Results show that mechanically milling could obviously increase the reaction ability of boron; however, it couldn’t increase the active content of boron.The combustion properties and reaction mechanism of micron boron/lead oxide (Pb3O4) and nano/micron boron/barium chromate (BaCrO4) delay composition was investigated. Optical-electrical targets device was used to test the burn rates of the delay composites. Results show:(1) burn rate of B/Pb3O4delay composites was linearly increased with the content of boron in the composite.The burn rate of treated boron delay composition was2.2times of the aging boron delay composition.(2)Burn rates of nano B/BaCrO4delay composition were bigger than that of micron boron delay composition, and burn rates of delay composition with treated boron were bigger than with aging boron.更多还原