【作者】 王建；

【导师】 聂福德；

【作者基本信息】 西南科技大学 ， 化学工程与技术， 2022， 硕士

【摘要】 硼（B）具有较高的能量密度,在固体推进剂、炸药和烟火剂中具有广泛的应用前景。然而B表面的惰性氧化层（B₂O₃）,导致点火延迟时间长和燃烧效率低等问题。为此,本文主要采用表面功能化技术,选用高活性的纳米铝（nano-Al）和氟化石墨烯（FG）对B粉表面功能化包覆,以改善B粉的点火和燃烧性能。系统研究了表面功能化B粉和硝酸钾（KNO₃）、氟化石墨（GF）两种氧化剂的点火和燃烧性能。在此基础上,基于B粉在两种氧化剂中的点火燃烧性能,采用乳化溶剂挥发法构建了一种B/Al/PTFE的多元复合含能微球,提升了含B复合含能材料的燃烧和压力输出特性。主要研究内容如下:（1）通过溶剂挥发法成功制备了nano-Al和FG表面功能化的B粉,实现了具有不同包覆量的B粉的制备。通过对表面功能化的B粉进行SEM、XPS、EDS和XRD的表征,证明了nano-Al和FG在B粉表面形成了均匀的壳层结构,并且随着包覆量的增加,壳层结构变得更致密。（2）选用KNO₃为氧化剂,系统研究了表面功能化B粉在KNO₃中的点火和燃烧特性。DSC结果表明,nano-Al、FG表面功能化B粉在KNO₃中反应热分别是1116.83J/g和862.69 J/g,高于未活化的B粉（823.39 J/g）。CO₂激光点火测试表明,当nano-Al涂层含量为8 wt%时具有最短的点火延迟时间（75 ms）,远低于未活化的B粉（109 ms）。点火燃烧和密闭爆发测试结果表明,表面功能化的B粉的火焰高度和峰值压力随着nano-Al和FG含量的增加,表现出先减小后增加的趋势。此外,探索了B/O质量比下表面功能化B在KNO₃中的点火和燃烧性能规律。当B/O比为7:3时,表面功能化B粉具有最小点火延迟时间,分别为94 ms和148 ms;而当B/O比为4:6时具有最高压力,分别为88 k Pa和59 k Pa。（3）选用含氟化合物GF为氧化剂,详细研究了表面功能化B粉在GF中的点火和燃烧特性。DSC结果表明,当B粉表面分别包覆6 wt%的nano-Al和2 wt%的FG时,具有最大的反应热5.612 k J/g和5.474 k J/g,大于未活化的B粉2.569 k J/g。CO₂激光点火测试表明,相较于未活化的B粉（120 ms）,表面功能化B粉的点火延迟时间可降低到116 ms和88 ms。点火燃烧和密闭爆发器测试表明,与nano-Al相比,FG更有利于增强B的燃烧和压力输出性能。此外,研究了不同B/GF质量比下,表面功能化B的点火和燃烧规律。当B/GF质量比为4:6时,具有最短的点火延迟时间（85 ms和72 ms）;当B/GF质量比为2:8时,具有强烈的燃烧和快速的火焰传播。（4）基于表面功能化B的点火燃烧规律研究,通过乳液溶剂蒸发法构建了具有不同B/Al质量比的B/Al/PTFE三元复合高能微球,研究了该复合微球的燃烧和压力输出性能。形貌和结构分析表明,微球内部各组分分布均匀、结合紧密,外观呈现出直径约为400μm的呈单分散性和高度球形的球形结构。点火燃烧试验和密闭爆发试验表明,微球最短的燃烧持续时间（200 ms）小于物理混合样品（315 ms）,最大的峰值压力（821.25 k Pa）大于物理混合样品（632.43 k Pa）。此外,通过调整B/Al质量比可以实现微球能量密度和反应性的调节。DSC结果表明,随着B/Al质量比的下降,放热量会先增加后减小,当B/Al质量比为21/9时,拥有最大的放热量（4.904 k J/g）。点火燃烧试验和密闭爆发试验表明,随着B/Al质量比的下降,反应性会逐渐增加,当B/Al质量比为0/30时,微球具有最低短的燃烧持续时间（200 ms）和最强的压力输出性能（821.25 k Pa和1831.18 MPa/s）。本文提出的表面功能化方法,为制备具有低点火延迟时间和高燃烧效率的B颗粒提供了一种新的技术途径,所制备的nano-Al和FG表面功能化的B粉具有降低的点火延迟时间和改善的燃烧反应性能。此外,本文提出了一种乳化溶剂挥发法,成功构建了具有多孔微结构的B/Al/PTFE多元复合微球,实现了含B复合含能材料燃烧和压力输出性能的提升。本文所制备的表面功能化B和含B复合微球在推进剂和炸药领域具有较好的应用前景。更多还原

【Abstract】 Boron（B）has wide application in propellants,explosives,and pyrotechnics due to its high energy density.However,B has the problems of long ignition delay time and low combustion efficiency resulting from the limitation of its surface inert oxide（B₂O₃）.Therefore,to improve the ignition and combustion properties,the surface functionalization technology was used in this paper.Nano-Al and Fluorographene（FG）were selected to functionalize the surface of boron.On this basis,the ignition and combustion performance of surface functionalized boron in potassium nitrate（KNO₃）and graphite fluoride（GF）oxidant environments were studied in detail.Based on the ignition and combustion performance of boron in two oxidants,we successfully constructed a B/Al/PTFE energetic composite with a microsphere-like structure by emulsion solvent evaporation method to improve the reactivity of B-containing energetic materials.The main research contents involved in this paper are as follows:1.The nano-Al/FG surface-functionalized boron with different coating amounts were successfully prepared by the solvent evaporation method.The surface-functionalized boron was characterized by SEM,XPS,EDS,and XRD,and it was proved that nano-Al and FG formed uniform shell structures on the surface of boron,which became more compact with the increase of coating amount.2.When the oxidant is KNO₃,the ignition and combustion performances of surface functionalized boron were systematically studied.DSC results show that the reaction heat of nano-Al and FG surface functionalized boron in KNO₃ is 1116.83 J/g and 862.69 J/g,respectively,which is higher than that of raw boron（823.39 J/g）.The CO₂ laser ignition test shows that when the content of nano-Al coating is 8 wt%,the ignition delay time（75 ms）is lower than that of raw boron（109 ms）.Ignition combustion test and closed bomb test results show that the flame height and peak pressure of surface-functionalized boron decrease first and then increase with the increase of nano-Al and FG content.In addition,the ignition and combustion properties of surface functionalized boron with different B/O mass ratios were explored.When the B/O ratio is 7:3,the surface functionalized boron has the minimum ignition delay time of 94 ms and 148 ms,respectively.When the B/O ratio is 4:6,the maximum pressure is 88 k Pa and 59 k Pa,respectively.3.When the oxidant is GF,the ignition and combustion performances of surface functionalized boron were studied in detail.DSC results show that when boron is coated with 6 wt%nano-Al and 2 wt%FG,respectively,the maximum reaction heats are 5.612 k J/g and 5.474 k J/g,which were higher than the raw boron（2.569 k J/g）.The CO₂ laser ignition test shows that compared with the raw boron（120 ms）,the ignition delay time of the surface-functionalized boron can be reduced to 116 ms and 88 ms,respectively.The ignition combustion test and closed bomb test show that FG is more conducive to enhancing the combustion and pressure output performance of boron than nano-Al.In addition,the ignition and combustion performances of surface functionalized boron under different B/GF mass ratios were studied.When B/GF mass ratio is 4:6,it has the shortest ignition delay time（85ms and 72 ms）.When B/GF mass ratio is 2:8,it has the strongest combustion and fastest flame propagation.4.Based on the ignition and combustion performances of surface functionalized boron,the B/Al/PTFE composite microspheres with different B/Al mass ratios were prepared by the emulsion solvent evaporation method.Morphology and structure analysis shows that the components were evenly distributed and closely combined.The microspheres show a monodisperse and highly spherical structure with a diameter of about 400μm.Ignition combustion test and closed bomb test show that the shortest combustion duration time（200ms）of the microspheres is less than that of the physical mixture sample（315 ms）,and the maximum peak pressure（821.25 k Pa）is higher than that of the physical mixture sample（632.43 k Pa）.In addition,the energy density and reactivity of microspheres can be tuned by adjusting the B/Al mass ratio.DSC results show that with the decrease of the B/Al mass ratio,the heat release increases first and then decrease.When the B/Al mass ratio is 21/9,it has the maximum heat release（4.904 k J/g）.The ignition combustion test and closed bomb test show that the reactivity increased gradually with the decrease of the B/Al mass ratio.When the B/Al mass ratio is 0/30,the microspheres had the lowest combustion duration time（200 ms）and the strongest pressure output performance（821.25 k Pa and 1831.18 MPa/s）.The surface functionalization method proposed in this paper provides a new technical approach to improve the ignition and combustion performances of boron.The prepared nano-Al and FG surface functionalized boron have reduced ignition delay time and improved combustion performance.In addition,this paper proposed an emulsion-solvent evaporation method to construct the B/Al/PTFE composite microspheres with porous microstructure to achieve the improved combustion and pressure output performance of B-containing energetic materials.The surface functionalized boron and the microspheres prepared in this paper have good application prospects in the field of propellants and explosives.更多还原