1996 Fiscal Year Final Research Report Summary
Development of a Large-Diameter Thermal Plasma Processing Device and its Application to Synthesis of Thermoelectric Materials
| Project/Area Number |
07558066
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 試験 |
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| Research Field |
プラズマ理工学
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| Research Institution | Yamaguchi University |
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Principal Investigator |
FUKUMASA Osamu Yamaguchi University, Faculty of Engineering, Professor, 工学部, 教授 (20026321)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAMURA Koh Japan Ultra-high Temperature Materials Research Center (JUTEM), Chief Researcher, 山口研究所, 研究部長
SAKIYAMA Satoshi Yamaguchi University, Faculty of Engineering, Research Associate, 工学部, 助手 (60162327)
KOYANAGI Tsuyoshi Yamaguchi University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (90178385)
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| Project Period (FY) |
1995 – 1996
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| Keywords | plasma jet / low-pressure thermal plasma processing / plasma spraying / alkari metal thermoelectric converter / beta" -alumina / computer tomography / diamond synthesis |
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| Research Abstract |
Thermal plasma jet operated under reduced pressure has a great potential for synthesizing new materials, because of its high speed, high gas temperature and large plasma volume. Therefore, we have newly designed the plasma reactor composed of the forced constricted type plasma jet generator and the feed ring. In order to clarify the application feasibility of this reactor to fine plasma processing for materials, the behavior of the plasma jet has been discussed.
Findings are as follows :
(1) Under low pressure, high temperature and high velocity regions of the plasma jet are expanded. With the use of this expanding plasma jet, the dense film without vesicles is obtained and the film thickness is easily controlled.
(2) Under low pressure, the hardness and the adhesion strength of functionally gradient materials are found to be high.
(3) Under not only atmospheric pressure but also low pressure, thin-films of beta" -alumina are successfully synthesized from the powder mixtures, i.e.alpha-Al_2O_3, Na_2CO_3 and MgO.Synthesis of beta" -alumina depends on jet power and the distance from the feed ring exit to the substrate.
(4) When pure diamond films are synthesized, the ratio of CH_4 flow rate to H_2 flow rate is lower than a certain critical value. Namely, the intensity of CH/H_<alpha> in the vicinity on the substrate has strong effect on pure diamond film deposition.
(5) The computer tomography technique should be applicable to the diagnostics of asymmetric plasma jets.
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