| Project/Area Number |
63302059
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| Research Category |
Grant-in-Aid for Co-operative Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
溶接工学
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| Research Institution | Osaka University |
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Principal Investigator |
MARUO Hiroshi Osaka University, Faculty of Engineering, Professor, 工学部, 教授 (50028982)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAKE Masashi Osaka University, Faculty of Engineering, Professor, 溶接工学研究所, 教授 (40029286)
MATSUNAWA Akira Osaka University, Faculty of Engineering, Professor, 溶接工学研究所, 教授 (20029119)
INOUE Katsunori Osaka University, Faculty of Engineering, Professor, 溶接工学研究所, 教授 (90029067)
HIRATA Yoshinori Osaka University, Faculty of Engineering, Lecturer, 工学部, 講師 (00116089)
MIYAMOTO Isamu Osaka University, Faculty of Engineering, Lecturer, 工学部, 講師 (90029273)
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| Project Period (FY) |
1988 – 1990
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥39,200,000 (Direct Cost: ¥39,200,000)
Fiscal Year 1990: ¥6,000,000 (Direct Cost: ¥6,000,000)
Fiscal Year 1989: ¥16,300,000 (Direct Cost: ¥16,300,000)
Fiscal Year 1988: ¥16,900,000 (Direct Cost: ¥16,900,000)
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| Keywords | Excimer laser / CO_2 laser / CVD / TOF / Admission gas / Kinetic energy / Ionization / Evaporation / YAGレ-ザ / 不安定共振器 / マスクプロジェクション / 分解粒子 / 表面粗さ / セラミックス / CO_2レーザ / YAGレーザ / ZnSeレンズ / 強度分布 / 熱分解 / クラック / 曲げ強度 |
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| Research Abstract |
Optics and diagnostics for focusing and shaping lasers were discussed. Mechanism of surface processing and modification of metal and ceramics was analyzed by using CO_2, YAG and excimer lasers, and properties of surface processing and modification were also characterized. It was shown that lasers are very effective source for surface processing and modifications. Results obtained are summarized as follows :
(1) Intensity distribution and focal position of CO_2, YAG and excimer lasers were measured by a newly developed diagnostic system. Change in focal length of ZnSe lens due to optical distortion induced thermally by high power CO_2 laser beam was also analyzed both theoretically and experimentally. Intensity distribution near focus position was shown to change within a short pulse duration, 30nsec, of excimer laser.
(2) LSV optics provided shaping efficiency as high as 96% with variable shape of beam spot, which enables variable case depth with optimized surface temperature. Transformation hardening using LSV optics provided hardened depth up to 2.5mm without any surface coating. Etyle-silicate was useful as a binder for metal powder in laser cladding, which provides absorptivity of about 60% without any porosity formation.
(3) Surface processing of ceramics was compared between CO_2, YAG and excimer (ArF, KrF and XeF) lasers. Negligible heat affected zone without cracks were observed at high peak powers and short pulse lengths like excimer lasers, although the processing speed becomes much smaller than CO_2 and YAG lasers of normal pulse.
(4) Spectral analysis and TOF technique were used to analyze laser PVD phenomenon. In excimer laser, the flight velocities of vapored particles were as fast as 40-50 km/sec, and considerable amount of particles were excited and ionized. Excimer laser provided fine films with very high hardness, which is larger than target ceramics. The stoichiometry Si_3N_4 film by LPVD was obtained with admission gas of N_2.
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