TY - JOUR
T1 - Microstructural characteristics of ball-milled self-sintered ex situ MgB2 bulks
AU - Shimada, Yusuke
AU - Hata, Satoshi
AU - Ikeda, Ken Ichi
AU - Nakashima, Hideharu
AU - Matsumura, Syo
AU - Tanaka, Hiroya
AU - Yamamoto, Akiyasu
AU - Shimoyama, Jun Ichi
AU - Kishio, Kohji
N1 - Publisher Copyright:
© 2002-2011 IEEE.
PY - 2015/6/1
Y1 - 2015/6/1
N2 - The ex situ method yields MgB2 samples with high packing factor. However, the critical current density of MgB2 bulks and wires fabricated using the ex situ method (ex situ MgB2) requires improvement for practical use because of insufficient connectivity. In this study, we evaluated the microstructure of self-sintered ex situ MgB2 bulks fabricated from laboratory-made ball-milled powder. We observed that green compacts of the ball-milled bulks contain fine MgB2 grain aggregates and a decreased gap length between MgB2 grain aggregates compared with those prepared without ball-milling. Therefore, the number of connections between the MgB2 grain aggregates and current path increased. However, the width of the connections between MgB2 grain aggregates remained narrow, suggesting the importance of controlling the initial microstructure of green compacts, such as the size of MgB2 grain aggregates and packing factor, by optimizing milling and pressing conditions.
AB - The ex situ method yields MgB2 samples with high packing factor. However, the critical current density of MgB2 bulks and wires fabricated using the ex situ method (ex situ MgB2) requires improvement for practical use because of insufficient connectivity. In this study, we evaluated the microstructure of self-sintered ex situ MgB2 bulks fabricated from laboratory-made ball-milled powder. We observed that green compacts of the ball-milled bulks contain fine MgB2 grain aggregates and a decreased gap length between MgB2 grain aggregates compared with those prepared without ball-milling. Therefore, the number of connections between the MgB2 grain aggregates and current path increased. However, the width of the connections between MgB2 grain aggregates remained narrow, suggesting the importance of controlling the initial microstructure of green compacts, such as the size of MgB2 grain aggregates and packing factor, by optimizing milling and pressing conditions.
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U2 - 10.1109/TASC.2014.2379928
DO - 10.1109/TASC.2014.2379928
M3 - Article
AN - SCOPUS:84923869779
SN - 1051-8223
VL - 25
JO - IEEE Transactions on Applied Superconductivity
JF - IEEE Transactions on Applied Superconductivity
IS - 3
M1 - 6983557
ER -