| Project/Area Number |
22860019
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| Research Category |
Grant-in-Aid for Research Activity Start-up
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| Allocation Type | Single-year Grants |
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| Research Field |
Physical properties of metals
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| Research Institution | The University of Tokyo |
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Principal Investigator |
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| Project Period (FY) |
2010 – 2011
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| Project Status |
Completed (Fiscal Year 2011)
|
| Budget Amount *help |
¥3,146,000 (Direct Cost: ¥2,420,000、Indirect Cost: ¥726,000)
Fiscal Year 2011: ¥1,508,000 (Direct Cost: ¥1,160,000、Indirect Cost: ¥348,000)
Fiscal Year 2010: ¥1,638,000 (Direct Cost: ¥1,260,000、Indirect Cost: ¥378,000)
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| Keywords | 超伝導材料 / ナノ材料 / 環境材料 |
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| Research Abstract |
We have studied the microstructure, normal-state electrical connectivity and critical current density of ex-situ MgB_2 polycrystalline bulks prepared using systematically varied heating conditions under ambient pressure. The samples heated at high-temperatures of～900℃for a long period showed an increased packing factor, a larger intergrain contact area and a significantly improved electrical connectivity, all of which show the evidence of solid-state self-sintering of MgB_2. The sintered ex-situ MgB_2 bulks from the laboratory-made prereacted MgB_2 powder showed largely enhanced connectivity of～20%, which is the highest among pressureless ex-situ MgB_2 bulks, wires and tapes. Owing to the improved inter-grain coupling, high critical current density exceeding 0. 3 MA/cm^2 at 20 K under self-field was achieved. This study shows that moderately high-temperature, long-time processing is a simple but forcible way to extract the superior current carrying potential of high bulk density ex-situ MgB_2 through strengthening of inter-grain coupling by the self-sintering.
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