Development of Equipment Generating Ultra-fine particle for Functionally Gradient Materials.

1990年，两项研究建立了超细颗粒（UFP）的形成。一种是在直流电弧放电的阳极上处理金属（Ti，Al）基底形成UFP。在两种情况下的产品和条件的形成进行了研究，添加氮气或氢气作为反应气体的等离子体支持氩气。二是射频氩等离子体和铝粉系统，它与氩等离子体气体中加入的氧气反应。这是用类似于液滴燃烧的模型进行的数值计算。用我们的方法发展功能梯度材料（FGM）存在两个主要问题：UFP的产率低和成分梯度平滑。在1991年，这些主要是关于铝粒子和氩/氧射频等离子体流系统的研究。前者是通过对流场的数值解和超细颗粒的贴壁估算来推测的，并采用了反应管设计以提高产率。此外，当使用氧气作为鞘气时，鞘气沿着反应管壁流动，并且获得高产率。后者，特别是金属与陶瓷的比率（这里，铝与氧化铝）通过调节向等离子体和/或鞘气中添加的氧的流速来解决。生产的氧化铝有α，γ，δ，rheta-氧化铝。在大多数情况下，这些成分相当稳定。这一施工控制问题仍有待于进一步解决。

In 1990, two studies were constructed for formation of ultra-fine particle (UFP). One was the formation of UFP with treatment of metal (Ti, AI) substrate on the anode of a dc arc discharge. The products and conditions of the formation were studied in two cases adding nitrogen or hydrogen as a reactive gas to the plasma supporting argon gas. Two was rf argon plasma and al-uminum powder system which reacts with oxygen added to the argon plasma gas. This was carried out numerically with the model similar to a combustion of liquid droplet.There are two major problems in the development of functionally gradient material (FGM) with our method ; low yield of UFP and smooth gradient of composition. In 1991, these were mostly examined about the system of aluminum particle and argon/oxygen rf plasma flow. The former was speculated by numerical solution about the flow fields and estimation of ultra-fine particle sticking to wall, and a reaction tube design was adopted for a high yield. Moreover, a sheath gas flew along the reaction tube wall and got a high yield when oxygen gas was used as a sheath gas. The latter, particularly metal to ceramics ratio (here, aluminum to alumina) was solved by adjustment of the flow rate of oxygen addition to the plasma and/or sheath gases. Produced alumina were alpha, gamma, delta, rheta-alumina. These composition was fairly constant in the most cases. This construction control still remain to be solved in future.