Wednesday, January 27, 2010

Efficient Mass Production of Carbon Nanocoils and Nanostructures Free of Defects and Contamination Unveiled by Japanese Team





A new reactor for the efficient mass production of carbon nanostructures free of defects and contamination has been jointly patented by Japan Science and Technology Agency (Saitama, JP), Public University Corporation Osaka Prefecture University (Osaka, JP), Taiyo Nippon Sanso Corporation (Tokyo, JP), Otsuka Chemical Co., Ltd. (Osaka, JP) and Nissin Electric Co., Ltd. (Kyoto, JP)

The inventors of the apparatus include Yoshikazu Nakayama (Hirakata, JP), Hiroyuki Tsuchiya (Kyoto, JP), Yugo Higashi (Kyoto, JP), Toshiki Goto (Osaka, JP), Keisuke Shiono (Osaka, JP), Takeshi Nagasaka (Tokyo, JP) and Nobuharu Okazaki (Karushiki, JP).

According to the inventors in U.S. Pat. 7,651,668, the nanofabrication process is an improved chemical vapor deposition process using novel convection and shielding equipment. The production process consists of:  a material gas and a catalyst that are introduced through a material supplying tube path and a catalyst supplying tube path together with a carrier gas into a reactor equipped on its outer periphery with a heat applicator for thermally decomposing the material gas.

The reactor has a convention regulator fitted to the discharge end of the catalyst supplying tube path. The convection regulator covers an edge side of the reactor to regulate gas flow in the reactor so that the flow does not reach the edge side. Due to this, a convection state can be efficiently produced in a reaction region. Consequently, it becomes possible to prevent contamination defect caused by accumulation/adherence of concretion of catalyst, which was generated by aggregation of cooled catalyst in the low-temperature region of the reactor and a decomposition product of the material gas. Thus the efficiency of carbon nanostructure production can be improved, say the inventors. The reactor working temperature is 500.degree. C.

The convection reactor system ensures more efficient production of carbon nano structures.  The device can cope with the variation in production states of carbon nano structure and so provides superior versatility in manufacturing carbon nano structure.

With the device structure, it is possible to prevent a decrease in temperature in the vicinity of the introduction section at the time of introducing the material gas and/or the catalyst into the reactor. By this method, the contamination due to accumulation of concretion of the catalyst or material gas decomposition product can be prevented. Further, it is also possible to enlarge the reaction region to the introduction section, to incrase production efficiency of carbon nano structures.   The construction materials and workings of the mass production apparatus are described in great detail in U.S. Patent 7,651,668


Figure 1 is schematic structure view showing an entire structure of a production device for a carbon nano structure.  




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