Abstract
The purpose of this research is to control the condensation process of SiC powder from SiCl4 and CH4 in a “hybrid plasma” which is characterized by the superposition of DC arc jet and RF plasma. In the previous paper, we have already reported the “reactive quanching method” may control the composition and particle size of products. In order to study more quantitatively, we have developed a new designed ring-slit, which could make it possible to change its slit width (Ws) accurately from 400 to 30 μm. By using it, we firstly investigated the decomposition and condensation processes of CH4 by changing the total flow rate (Qs) and linear velocity (Vs) of quenching gas. Based on the result, we synthesized SiC powder from SiCl4 and CH4 and investigated the condensation process of SiC. These experimental results revealed that the decomposition and condensation of CH4 and the condensation process of SiC was affected by Vs and Qs. Especially, it was found that the composition of SiC, and the particle size were affected by both of Vs and Qs, and only Qs, respectively. In other words, the decomposition and condensation of CH4 was considered to be a key factor to control the composition of SiC powder. Further more, the new designed ring-slit system made it possible to control not only the composition of SiC powders but also particle size, and is considered to be an effective device for independent control of gas phase reaction and condensation processes in various chemical systems.
