R&D of Highly Oriented Graphite Block made from Graphitization of Multi-Polyimide Films with Addition of Guest Element

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Fabrication of highly oriented graphite block was carried out from polyimide films with addition and doping of boron or rare earth elements for the purpose of obtaining a high performance graphite monochrometer. From the research of the first year it was found that graphitization of polyimide films with addition of boron or La proceeded more than the films with no addition by heat treatment at 1500ﾟC - 2500ﾟC.But degree of orientation was degraded slightly for the films with addition. Thinner film of 25 mum in thickness was much better for crystallinity and orientation than those film with thickness of 125mum. In the research of the second year fabrication of highly oriented graphite block was fabricated by hot-pressing method. Multi-layrs polyimide film with addition of boron or lanthanum was set in a graphite mold and carbonized at 1500ﾟC under vacuum condition, and then heat-treated at 2000ﾟC under hot-press coundition. Degree of graphitization was also accelerated by boron or lanthanum addition. Joining between films was better than the films without guest element addition. Joining between films was thought to be promoted by diffusion of boron or lanthanum atoms under hot-press condition. After hot pressing the sample was heat-treated again at 2500ﾟC under normal pressure condition for obtaining high degree of graphitization. However, some separation between films was observed. New processing for highly performance graphite monochrometer could be developed through this research. To obtain perfect highly oriented graphite block without any flaw is future research subject.