Melt-Dispersion Mechanism for Energetic Reactions of Aluminum Nanoparticles

铝纳米粒子高能反应的熔融分散机制

• 批准号: 1104518
• 负责人: Valery Levitas
• 金额: $ 16.65万
• 依托单位: Iowa State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-15 至 2012-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1104518&HistoricalAwards=false
• 关键词: Melt; Dispersion; Mechanism; Energetic; Reactions

CBET-0755236LevitasAluminum particles are becoming integrated into energetic formulations and considered for overlapping technologies such as materials synthesis and thermites for ordnance applications. Recently, a new mechanochemical mechanism has been introduced that shows potential for understanding extremely fast Al nanoparticle reactions. This theory applies during fast heating of Al nanoparticles, where the volume change due to melting of the Al core encased in an alumina shell induces extreme pressures of 1-2 GPa, resulting in a spallation of the oxide shell. The unbalanced pressure between the Al core and exposed surface creates an unloading wave with high tensile pressures, resulting in dispersion of small liquid Al clusters that fly at high velocity. Thus, nanoparticle reactions are not limited by diffusion. The proposed melt-dispersion mechanism is the only existing explanation that resolves a number of basic puzzles in nano-Al combustion. The goal of this project is to define the main conditions and controlling physical parameters for operation of the melt-dispersion mechanism for reactions of Al nanoparticles; to extend this mechanism for micron-scale particles; and to utilize obtained fundamental knowledge for the improvement of Al-based formulations. The following tasks will be considered: (a) develop comprehensive theories for physical processes participating in the melt-dispersion mechanism, (b) synthesize Al particles based on theoretical predictions and new particle design concepts, (c) study implications of the melt-dispersion mechanism experimentally, (d) expand the melt-dispersion mechanism to micron-scale particles, and (e) predict and experimentally confirm methods that will improve the reactivity of Al particles in various formulations. Beyond the potential for technological impact, a mentoring program will be developed where undergrads work with grad students in a research environment. In addition, nanoparticle combustion will be integrated into the combustion curriculum and a continuing-education program in energetic materials. The investigators also plan to organize special symposia devoted to "mechanochemical" processes at various international conferences.

CBET-0755236 Levitasaluminum颗粒正在整合到能量制剂中，并考虑用于重叠的技术，例如材料合成和用于弹药应用的热线。最近，引入了一种新的机械化学机制，该机制显示了理解极快的Al纳米颗粒反应的潜力。该理论适用于Al纳米颗粒的快速加热，其中由于包裹在氧化铝壳中的Al核的熔化引起的体积变化会诱导1-2 GPA的极端压力，从而导致氧化物壳的剥落。 Al芯与裸露的表面之间的不平衡压力产生了带有高拉伸压力的卸载波，从而导致在高速速度飞行的小液体Al簇分散。因此，纳米颗粒反应不受扩散的限制。提出的熔融分散机制是唯一解决纳米燃烧中许多基本难题的现有解释。该项目的目的是定义主要条件和控制物理参数，以用于熔化纳米颗粒反应的熔体分散机制的操作；扩展这种机制的微米级颗粒；并利用获得的基本知识来改善基于Al的配方。 The following tasks will be considered: (a) develop comprehensive theories for physical processes participating in the melt-dispersion mechanism, (b) synthesize Al particles based on theoretical predictions and new particle design concepts, (c) study implications of the melt-dispersion mechanism experimentally, (d) expand the melt-dispersion mechanism to micron-scale particles, and (e) predict and experimentally confirm methods that will improve the reactivity of各种配方中的颗粒。除了具有技术影响的潜力之外，还将开发一项指导计划，其中本科生在研究环境中与研究生合作。 此外，纳米颗粒燃烧将集成到燃烧课程中，并在能量材料中进行持续的教育计划。研究人员还计划组织特殊的研讨会，该研讨会致力于各种国际会议上的“机械化学”过程。