| 摘要 |
PURPOSE:To prepare fine particles and also prevent fine particles from adhering to the inner wall of an inner tube by supplying reactive gas with high pressure into an outer tube and reactive gas with less high pressure into an inner tube in a double tube consisting of a porous inner tube and an outer tube having a space therebetween. CONSTITUTION:Reactive gas A is fed into an inner tube 1, while reactive gas B is fed into a space 5. Although reactive gas B depends on the porous pore diameter and void content of the inner tube wall 1 and stoichiometric ratio with the flow of reactive gas A, the pressure of reactive gas B is maintained slightly higher than that of reactive gas A. Thus, reactive gas B passes through the porous tube wall of the inner tube 1 and is introduced into the inner tube 1, where reactive gas A and reactive gas B are reacted to form fine particles. As reactive gas A, titanium tetrachloride or the like is used, while reactive gas B is a different kind from reactive gas A and can form fine particles by reacting with reactive gas A. For example, ammonia or the like is used as reactive gas B. |
