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Fabrication of highly dense MgB2 bulk at ambient pressure

Journal Article


Abstract


  • We report an in situ heat-treatment technique for the preparation of near-fully-dense un-doped MgB2 bulks that also provides very strong in-field pinning. The high density was achieved without using high-pressure apparatus. The heat-treatment of compacted boron sealed in a Ta tube with Mg pellets employs a short high-temperature sintering at 1100 degrees C first, followed by a low-temperature annealing below 660 degrees C. A high density of 2.5 g cm(-3) (95% of the theoretical density) was achieved in the bulks treated by the two-step process. The in-field J(c) is nearly one order of magnitude higher than for the samples prepared by single-step sintering at high or low temperature. Microstructural analysis suggested a unique feature of well-connected small grains with a high level of disorder in the MgB2 samples created by the two-step process.

Authors


  •   Maeda, Minoru (external author)
  •   Zhao, Yue
  •   Dou, Shi Xue
  •   Nakayama, Yoshitake (external author)
  •   Kawakami, T (external author)
  •   Kobayashi, Hideo (external author)
  •   Kubota, Y (external author)

Publication Date


  • 2008

Citation


  • Maeda, M., Zhao, Y., Dou, S. Xue., Nakayama, Y., Kawakami, T., Kobayashi, H. & Kubota, Y. (2008). Fabrication of highly dense MgB2 bulk at ambient pressure. Superconductor Science and Technology, 21 (3), 032004-1-032004-4.

Scopus Eid


  • 2-s2.0-43649084924

Ro Metadata Url


  • http://ro.uow.edu.au/aiimpapers/96

Start Page


  • 032004-1

End Page


  • 032004-4

Volume


  • 21

Issue


  • 3

Abstract


  • We report an in situ heat-treatment technique for the preparation of near-fully-dense un-doped MgB2 bulks that also provides very strong in-field pinning. The high density was achieved without using high-pressure apparatus. The heat-treatment of compacted boron sealed in a Ta tube with Mg pellets employs a short high-temperature sintering at 1100 degrees C first, followed by a low-temperature annealing below 660 degrees C. A high density of 2.5 g cm(-3) (95% of the theoretical density) was achieved in the bulks treated by the two-step process. The in-field J(c) is nearly one order of magnitude higher than for the samples prepared by single-step sintering at high or low temperature. Microstructural analysis suggested a unique feature of well-connected small grains with a high level of disorder in the MgB2 samples created by the two-step process.

Authors


  •   Maeda, Minoru (external author)
  •   Zhao, Yue
  •   Dou, Shi Xue
  •   Nakayama, Yoshitake (external author)
  •   Kawakami, T (external author)
  •   Kobayashi, Hideo (external author)
  •   Kubota, Y (external author)

Publication Date


  • 2008

Citation


  • Maeda, M., Zhao, Y., Dou, S. Xue., Nakayama, Y., Kawakami, T., Kobayashi, H. & Kubota, Y. (2008). Fabrication of highly dense MgB2 bulk at ambient pressure. Superconductor Science and Technology, 21 (3), 032004-1-032004-4.

Scopus Eid


  • 2-s2.0-43649084924

Ro Metadata Url


  • http://ro.uow.edu.au/aiimpapers/96

Start Page


  • 032004-1

End Page


  • 032004-4

Volume


  • 21

Issue


  • 3