An MgB2 Superconducting Joint with its own Heat-Treatment Schedule
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20ja146_full.pdf
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Author(s)
Tanaka, Hiromi
Li, Yi
Choi, Yoonhyuck
Park, Dongkeun
Lee, Wooseung
Tanaka, Hideki
Bascuñán, Juan
Iwasa, Yukikazu
Date Issued
December 2020
Journal
IEEE Transactions on Applied Superconductivity
Publisher
IEEE
Abstract
We suggested an MgB2 joint process with its own heat-treatment schedule to apply it for our 1.5-T MgB2 “finger” MRI magnet. In fabricating the MgB2 magnet, the optimal heat-treatment schedule to attain a reproducible and high critical current is different in a joint and a coil. To solve this problem, we introduced an additional heating system, which is composed of a cartridge heater and a thermocouple connected with a copper block, into a box-type furnace. Then, we carried out heattreatments with exclusively increasing the joint-part temperature above theMgmelting point of 645 °C—the jointwas actually heated up to 700 °C.We evaluated a critical current and a crystal structure of the obtained MgB2 joint. From experimental results, we found that the joint heated with the own heat-treatment schedule, which is 700 °C for 1 h+600°C for 11 h, showed a good Ic of over 450 A at 15K under self-field. The joint resistance was estimated by the coil operation for 18 days, and it was expected to be less than 10−12 Ω.
Description
Submitted for publication in IEEE Transactions on Applied Superconductivity
MIT Department
Massachusetts Institute of Technology. Plasma Science and Fusion Center
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1109/tasc.2021.3064517
