Production of Ultra Fine Particles by Gas Evaporation Technique

直径在10 ~ 100nm之间的超细颗粒（UFP）具有优越的电磁特性和其他性能，可以成为开辟新材料技术的关注焦点。为了充分利用这一材料元素的特性，应结合操作条件开发UFP的高效制造技术，将颗粒控制在均匀的尺寸和密度上。从这个角度出发，本研究探讨了饱和金属蒸汽自成核、颗粒生长和颗粒收集等气体蒸发技术中UFP产生的基本机理。以下是从调查中得出的总结。利用锌金属和电热船系统在ar -气体流场中制造UFP的实验结果，实验明确了颗粒特性与气体压力、金属和气体温度、气体速度等操作参数的关系。2. 考虑温度场和质量场的相互作用，分析了粒子的产生过程，包括自成核、生长和收集等过程。通过与实验结果的比较，对UFP的产生和输运过程进行了分析。推导出了UFP的生产速度和直径与操作参数的关系。3. 在上述发现的基础上，获得了UFP制造工艺的基本知识。

The ultra fine particles (UFP) between 10 to 100nm in diameter have so superior characteristics in electric magnetic and the other properties, that they can become the center of the attention to open up new material technology. To make the best use of this characteristics as an element of material, the high efficiency manufacturing technology of UFP should be developed in conjunction with the operating condition to control the particles at uniform size and density. From the standpoint,this study has been conducted to pursue the basic mechanism of UFP production in the gas evaporation techniques including the process of self-nucleation of saturated metal vapor, particle growth, and particle collection. The following are the summary deduced from the investigation.1. As the results of UFP manufacturing experiments in an Ar-gas flow field by using Zn metal and electric heating boat system, the particle characteristics were experimentally made clear in connection with the operating parameter such as the gas pressure, the metal and gas temperature, and the gas velocity. 2. The particle production, which consisted of the process such as self-nucleation, growing, and collection, was analyzed taking account of the interaction between the temperature and mass fields. As compared with the experimental results, the production and the transport process of UFP were clarified analytically. The production velocity and diameter of UFP were also deduced in relation to the operating parameter. 3. On the basis of the above findings, the fundamental knowledge of UFP manufacturing process was obtained.