Microstructural characteristics of ball-milled self-sintered ex situ MgB2 bulks

Yusuke Shimada, Satoshi Hata, Ken Ichi Ikeda, Hideharu Nakashima, Syo Matsumura, Hiroya Tanaka, Akiyasu Yamamoto, Jun Ichi Shimoyama, Kohji Kishio

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

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.

Original languageEnglish
Article number6983557
JournalIEEE Transactions on Applied Superconductivity
Volume25
Issue number3
DOIs
Publication statusPublished - Jun 1 2015

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balls
microstructure
Microstructure
Ball milling
pressing
Powders
critical current
wire
Wire
current density

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

Cite this

Microstructural characteristics of ball-milled self-sintered ex situ MgB2 bulks. / Shimada, Yusuke; Hata, Satoshi; Ikeda, Ken Ichi; Nakashima, Hideharu; Matsumura, Syo; Tanaka, Hiroya; Yamamoto, Akiyasu; Shimoyama, Jun Ichi; Kishio, Kohji.

In: IEEE Transactions on Applied Superconductivity, Vol. 25, No. 3, 6983557, 01.06.2015.

Research output: Contribution to journalArticle

Shimada, Yusuke ; Hata, Satoshi ; Ikeda, Ken Ichi ; Nakashima, Hideharu ; Matsumura, Syo ; Tanaka, Hiroya ; Yamamoto, Akiyasu ; Shimoyama, Jun Ichi ; Kishio, Kohji. / Microstructural characteristics of ball-milled self-sintered ex situ MgB2 bulks. In: IEEE Transactions on Applied Superconductivity. 2015 ; Vol. 25, No. 3.
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