Investigation of Nanoparticle Formation Using a Plasma Expansion Process

提出了一种实验性的， 纳米粒子理论研究 使用等离子体工艺合成。 碳化硅颗粒合成 将作为一个模型来研究， 涉及化学物质的系统 微晶的成核 的 实验装置将包括 热等离子体反应器 注入哪些反应物， 然后通过一个汇聚的 喷管 粒子会在 然后将其排出到一个 自由膨胀， 被压制了。 的优点 这种方法是：（1） 过程能够生成 窄尺寸纳米颗粒 喷嘴流场 环境可以 （3）关键工艺 诸如冷却速率之类的变量可以 （四）控制; 工艺可扩展为高速率 工业生产 一 高超音速撞击器位于 紧接着喷嘴的下游 将被用来收集粒子， 小至5 nm。 颗粒将 其特征在于技术， 扫描隧道显微镜和 高分辨透射 电镜 了理论 将开发模型， 对应于实验 条件，并结合 第一性原理分子动力学 团簇性质计算 用粒子动力学模型 成核和生长。 的 知识和技术基础将 被开发用于纳米颗粒 在等离子体反应中合成， 广泛的应用范围， 先进的材料。

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.