| Project/Area Number |
07650824
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural/Functional materials
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| Research Institution | Tokai University |
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Principal Investigator |
YAMADA Yutaka Tokai University, Faculty of Engineering, Professor, 工学部, 教授 (10266372)
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| Co-Investigator(Kenkyū-buntansha) |
TACHIKAWA Kyoji Tokai University, Faculty of Engineering, Professor, 工学部, 教授 (40197372)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1996: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1995: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Keywords | high-temperature superconductor / Bi system / Bi-2212 / diffusion process / critical current / bulk / Ag addition / current lead / バルク体 |
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| Research Abstract |
Bi-2212 oxide superconductors have been synthesized by the diffusion reaction between a high melting point Sr-Ca-Cu oxide substrate and a low melting point Bi-Cu oxide coating layr. The substrate with Sr : Ca : Cu atomic ratio of 2 : 1 : 2 is pressed into a cylindrical rod by CIP,and then sintered. The coating layr with Bi : Cu ratio of 2 : 1 and Ag_2O addition is coated around the surface of the substrate. The heat treatment is performed to produce the Bi-2212 diffusion layr at 820-860ﾟC.The Ag added to the coating layr enhances the diffusion reaction, and precipitates on the surface of the specimen. The Bi-2212 diffusion phase, formed through Bi_2 (Sr, Ca)_2Cu oxide phase, shows dense and oriented structure with plate-like grains. The transport Ic and Jc of the diffusion layr, about 150 mum in thickness, exceed 300 A and 2*10^4A/cm^2 up to 25 K under self-field, respectively. The transport Jc decreases with temperature, and is about 1*10^4A/cm^2 at 35 K under 0.5 T.Post annealing in inert gas atmosphere improves Tc and Jc at higher temperatures of the specimen. Present Bi-2212 oxide cylinders with large transport Ic and Jc as well as low contact resistance may be attractive as current leads for different kind of superconducting magnets.
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