Investigation of Nanoparticle Formation Using a Plasma Expansion Process

使用等离子体膨胀过程研究纳米颗粒的形成

• 批准号: 9118100
• 负责人: Joachim Heberlein
• 金额: $ 64.45万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-10-01 至 1995-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9118100&HistoricalAwards=false
• 关键词: Investigation; Nanoparticle; Formation; Using; Plasma

It is proposed an experimental and theoretical study of nanoparticle synthesis using a plasma process. Silicon carbide particle synthesis will be studied as a model of systems which involve chemical nucleation of microcrystals. The experimental apparatus will consist of a thermal plasma reactor into which reactants are injected and then expanded through a converging nozzle. Particles will nucleate in the nozzle, and then will exit to a free expansion so that coagulation is suppressed. The advantages of this approach are that (1) the process is capable of generating nanosize particles with narrow size distributions; (2) the nozzle flow environment can be well-characterized; (3) key process variables such as cooling rates can be controlled; and (4) the processcan be scaled for high-rate industrial production. A hypersonicimpactor located immediately downstream of the nozzle will be used to collect particles as small as 5 nm. Particles will be characterized by techniques such as scanning tunneling microscopy and high resolution transmission electron microscopy. A theoretical model will be developed which corresponds to the experimental conditions, and which combines first-principles molecular dynamics calculations of cluster properties with a dynamic model for particle nucleation and growth. The knowledge and technology base will be develop for nanoparticle synthesis in a plasma reaction, with a broad range of applications for advanced materials.

提出了利用等离子体工艺合成纳米颗粒的实验和理论研究。碳化硅颗粒的合成将作为涉及微晶化学成核的系统模型来研究。实验装置将由一个热等离子体反应器组成，反应物被注入其中，然后通过一个会聚喷嘴膨胀。颗粒将在喷嘴中成核，然后将自由膨胀，从而抑制凝固。该方法的优点是：(1)该工艺能够产生具有窄尺寸分布的纳米级颗粒；(2)可以很好地表征喷嘴流动环境；(3)可控制冷却速率等关键工艺变量；(4)该工艺可按比例进行高速率工业生产。位于喷嘴下游的高超音速撞击器将用于收集小至5纳米的颗粒。粒子将通过扫描隧道显微镜和高分辨率透射电子显微镜等技术进行表征。将建立一个与实验条件相对应的理论模型，它将团簇性质的第一性原理分子动力学计算与粒子成核和生长的动态模型相结合。将发展等离子体反应合成纳米颗粒的知识和技术基础，在先进材料方面具有广泛的应用。