1989 Fiscal Year Final Research Report Summary
Fundamental Studies on Purification of Reactive Metls by Laser irradiatio
| Project/Area Number |
63550493
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
金属精錬・金属化学
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
FUKUNAKA Yasuhiro Kyoto Univ., Dept. of Metallurgy, Research associate, 工学部, 助手 (60111936)
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| Project Period (FY) |
1988 – 1989
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| Keywords | purification / reactive metal / levitation / mass transfer / gas-metal reaction / laser / deoxidation / liquid film mass transfer coefficient |
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| Research Abstract |
The advanced technology has introduced a number of unique processing to refine the materials to ultra-purified grade by introducing another degree of freedom in the field of refining reaction which principle is completely different from that in conventional process. Electron or laser beam irradiation may provides such a degree of freedom. In the present course of researches, it was intended to understand the fundamental physical chemistry relevant to the refining reaction between molten reactive metal surface irradiated by laser beam and surrounding gas atmosphere. The model experiments to simulate such a situation were designed with the deoxidation or vaporization reaction between a levitated metal droplet and reducing gas atmosphere. First of all, crude metal would be refined by gas injection technique. Then, these molten reactive metals would be processed with the technique of cold crucible and laser irradiation.
The kinetics on the gas-metal reaction must be firstly elucidated at very low solute concentration. Some examples were tested for the deoxidation kinetics of Cu and Ni in Ar-H_22 stream. The extrapolated thermodynamic data based on the literature was combined with the mixed controlling model to estimate the liquid film mass transfer coefficient of 0.08 cms^<-1>.
Then, the surface temperatures of Ni, Ti, Zr and Nb were tried to measure by two-color pyrometer. The melting phenomena of these metals provided the good way to modify the temperature measurements. Moreover, the vaporization rates of these droplets supplied the gas film mass transfer coefficients. Most of fundamental kinetics on the refining reaction around the levitated drops were thus accumulated.
Based on these information, the effects of laser irradiation on the refining, reaction are now investigated by the present author. The most difficult problems are how to design the optical system for infrared region and how to measure the localized temperature around the laser irradiated area.
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