Microstructure in high-density MgB2 wires prepared by an internal Mg diffusion method

Yusuke Shimada; Yuuki Kubota; Satoshi Hata; Ken Ichi Ikeda; Hideharu Nakashima; Akiyoshi Matsumoto; Kazumasa Togano; Jahmahn Hur; Hiroaki Kumakura

doi:10.1109/TASC.2010.2091097

Microstructure in high-density MgB₂ wires prepared by an internal Mg diffusion method

Yusuke Shimada, Yuuki Kubota, Satoshi Hata, Ken Ichi Ikeda, Hideharu Nakashima, Akiyoshi Matsumoto, Kazumasa Togano, Jahmahn Hur, Hiroaki Kumakura

IMR - Materials Design Division

Research output: Contribution to journal › Article › peer-review

16 Citations (Scopus)

Abstract

Several reaction-induced diffusion processes to fabricate high-density MgB₂ materials are developed, and the critical current density (J_c) has been notably enhanced. In this study, microstructure in high-density MgB₂ wires fabricated by an internal Mg diffusion (IMD) process has been investigated. The inner reacted region of the wire heat-treated at 640 °C for 1 h shows dense polycrystalline MgB₂ of 20-200 nm in grain sizes. Fine MgO and Mg₂Si particles of 10-30 nm in sizes are dispersed in this region. On the other hand, the outer region near the Ta sheath is composed of unreacted B and SiC powders, fine MgO particles and small voids. Sizes of voids in the IMD MgB₂ wire are small compared with the PIT MgB₂ wire. Oxidation of Mg in the IMD process forms fine dispersion of MgO which may be effective for flux pinning.

Original language	English
Article number	5643189
Pages (from-to)	2668-2671
Number of pages	4
Journal	IEEE Transactions on Applied Superconductivity
Volume	21
Issue number	3 PART 3
DOIs	https://doi.org/10.1109/TASC.2010.2091097
Publication status	Published - 2011 Jun

Keywords

Heat treatment
MgB wire
Microstructure
Reaction-induced diffusion process

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10.1109/TASC.2010.2091097

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title = "Microstructure in high-density MgB2 wires prepared by an internal Mg diffusion method",

abstract = "Several reaction-induced diffusion processes to fabricate high-density MgB2 materials are developed, and the critical current density (Jc) has been notably enhanced. In this study, microstructure in high-density MgB2 wires fabricated by an internal Mg diffusion (IMD) process has been investigated. The inner reacted region of the wire heat-treated at 640 °C for 1 h shows dense polycrystalline MgB2 of 20-200 nm in grain sizes. Fine MgO and Mg2Si particles of 10-30 nm in sizes are dispersed in this region. On the other hand, the outer region near the Ta sheath is composed of unreacted B and SiC powders, fine MgO particles and small voids. Sizes of voids in the IMD MgB2 wire are small compared with the PIT MgB2 wire. Oxidation of Mg in the IMD process forms fine dispersion of MgO which may be effective for flux pinning.",

keywords = "Heat treatment, MgB wire, Microstructure, Reaction-induced diffusion process",

author = "Yusuke Shimada and Yuuki Kubota and Satoshi Hata and Ikeda, {Ken Ichi} and Hideharu Nakashima and Akiyoshi Matsumoto and Kazumasa Togano and Jahmahn Hur and Hiroaki Kumakura",

note = "Funding Information: Manuscript received August 03, 2010; accepted November 01, 2010. Date of publication November 22, 2010; date of current version May 27, 2011. This work was supported in part by Nanotechnology Support Project of the Ministry of Education, Culture, Sport, Science, and Technology (MEXT) and Grants-in-Aid from MEXT and in part by the Japan society for the Promotion of Science, Japan.",

year = "2011",

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T1 - Microstructure in high-density MgB2 wires prepared by an internal Mg diffusion method

AU - Shimada, Yusuke

AU - Kubota, Yuuki

AU - Hata, Satoshi

AU - Ikeda, Ken Ichi

AU - Nakashima, Hideharu

AU - Matsumoto, Akiyoshi

AU - Togano, Kazumasa

AU - Hur, Jahmahn

AU - Kumakura, Hiroaki

N1 - Funding Information: Manuscript received August 03, 2010; accepted November 01, 2010. Date of publication November 22, 2010; date of current version May 27, 2011. This work was supported in part by Nanotechnology Support Project of the Ministry of Education, Culture, Sport, Science, and Technology (MEXT) and Grants-in-Aid from MEXT and in part by the Japan society for the Promotion of Science, Japan.

PY - 2011/6

Y1 - 2011/6

N2 - Several reaction-induced diffusion processes to fabricate high-density MgB2 materials are developed, and the critical current density (Jc) has been notably enhanced. In this study, microstructure in high-density MgB2 wires fabricated by an internal Mg diffusion (IMD) process has been investigated. The inner reacted region of the wire heat-treated at 640 °C for 1 h shows dense polycrystalline MgB2 of 20-200 nm in grain sizes. Fine MgO and Mg2Si particles of 10-30 nm in sizes are dispersed in this region. On the other hand, the outer region near the Ta sheath is composed of unreacted B and SiC powders, fine MgO particles and small voids. Sizes of voids in the IMD MgB2 wire are small compared with the PIT MgB2 wire. Oxidation of Mg in the IMD process forms fine dispersion of MgO which may be effective for flux pinning.

AB - Several reaction-induced diffusion processes to fabricate high-density MgB2 materials are developed, and the critical current density (Jc) has been notably enhanced. In this study, microstructure in high-density MgB2 wires fabricated by an internal Mg diffusion (IMD) process has been investigated. The inner reacted region of the wire heat-treated at 640 °C for 1 h shows dense polycrystalline MgB2 of 20-200 nm in grain sizes. Fine MgO and Mg2Si particles of 10-30 nm in sizes are dispersed in this region. On the other hand, the outer region near the Ta sheath is composed of unreacted B and SiC powders, fine MgO particles and small voids. Sizes of voids in the IMD MgB2 wire are small compared with the PIT MgB2 wire. Oxidation of Mg in the IMD process forms fine dispersion of MgO which may be effective for flux pinning.

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Microstructure in high-density MgB₂ wires prepared by an internal Mg diffusion method

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Keywords

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