| Project/Area Number |
14350390
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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 | 一般 |
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| Research Field |
Material processing/treatments
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| Research Institution | Akita Prefectural University |
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Principal Investigator |
TAKEDA Koichi Akita Prefectural University, System Science and Technology, Professor, システム科学技術学部, 教授 (20315641)
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| Co-Investigator(Kenkyū-buntansha) |
MARUTA Kaoru Tohoku University, Institute of Fluid Science, Assistant Professor, 流体科学研究所, 助教授 (50260451)
SUGIMOTO Masaya Akita Prefectural University, System Science and Technology, Associate Professor, 講師 (20291784)
KUMAGAI Seiji Akita Prefectural University, System Science and Technology, Assistant, 助手 (00363739)
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| Project Period (FY) |
2002 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥14,000,000 (Direct Cost: ¥14,000,000)
Fiscal Year 2005: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2004: ¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2003: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 2002: ¥6,400,000 (Direct Cost: ¥6,400,000)
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| Keywords | arc / cathode spot / vacuum / work function / oxide removal / surface roughness / 雰囲気圧力 / 電極間距離 / クリーニング |
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| Research Abstract |
Cathode spots of a vacuum arc are preferably produced on the metallic oxide. They remove the oxide selectively by evaporation and clean the metal surface. In this work investigators have studied the characteristic features of the cathode spots and understand physical background of the unique properties. Main results are summarized below.
(1)The analysis of surface using a Kelvin probe reveals that the preferable formation of cathode spots on the metallic oxide results from the lower work function of the oxide compared with pure metal.
(2)There exist two different modes of cathode spots produced on the metallic oxide. One has higher energy density than the other. The cathode spots with higher energy density contribute the high rate of oxide removal. The surface treated by high energy cathode spots becomes smoother than that by low energy cathode spots.
(3)Two different modes can appear on the same surface at the same time. The ratio of high energy spots to low energy ones depends on the surface condition. The application of NaOH or KOH to the cathode surface of the metal results in the increase of the ratio, which means the increase of the rate oxide removal. The addition of polyethylene glycol also contributes the increase of the removal rate.
(4)The hardness of the surface treated by the cathode spots increases because of the rapid solidification of the thin molten layer formed during the removal of oxide.
(5)Reduction of gap width between an anode and a cathode results in the increase of the energy efficiency of the oxide removal. The anode potential drop disappears in a gap width shorter than a critical value. In such condition, a major part of the input energy is consumed for the removal of oxide on the cathode.
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