Pore formation in in situ processed MgB2 superconductors

J. H. Yi; K. T. Kim; B. H. Jun; J. M. Sohn; B. G. Kim; J. Joo; C. J. Kim

doi:10.1016/j.physc.2009.05.190

Pore formation in in situ processed MgB₂ superconductors

J. H. Yi
, K. T. Kim
, B. H. Jun
, J. M. Sohn
, B. G. Kim
, J. Joo
, C. J. Kim

Korea Atomic Energy Research Institute

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

14 Scopus citations

Abstract

MgB₂ bulks were prepared by an in situ process which utilizes the reaction between boron and magnesium powder. The reaction time was fixed at 0.5 h and the temperature was changed from 600 °C to 1000 °C. The density decrease due to pore formation and mass (mainly magnesium) loss during the formation reaction of MgB₂ was observed in all samples. In addition to the pore formation, a pellet expansion which can be explained by the outgrowth of MgB₂ grains was also observed. Two different mechanisms were adopted to explain the pore formation; Kirkendall pores formed at a temperature below the melting point (m.p.) of magnesium by a difference in the diffusivity between magnesium and boron, and the pores formed at a temperature above the m.p. by melting of magnesium and a capillary movement. The density, T_c and J_c results suggest that the current carrying capacity can be improved by a careful control of the process parameters regarding a pore evolution.

Original language	English
Pages (from-to)	1192-1195
Number of pages	4
Journal	Physica C: Superconductivity and its Applications
Volume	469
Issue number	15-20
DOIs	https://doi.org/10.1016/j.physc.2009.05.190
State	Published - 15 Oct 2009

Keywords

In situ process
MgB superconductor
Pore formation
Reaction

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10.1016/j.physc.2009.05.190

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title = "Pore formation in in situ processed MgB2 superconductors",

abstract = "MgB2 bulks were prepared by an in situ process which utilizes the reaction between boron and magnesium powder. The reaction time was fixed at 0.5 h and the temperature was changed from 600 °C to 1000 °C. The density decrease due to pore formation and mass (mainly magnesium) loss during the formation reaction of MgB2 was observed in all samples. In addition to the pore formation, a pellet expansion which can be explained by the outgrowth of MgB2 grains was also observed. Two different mechanisms were adopted to explain the pore formation; Kirkendall pores formed at a temperature below the melting point (m.p.) of magnesium by a difference in the diffusivity between magnesium and boron, and the pores formed at a temperature above the m.p. by melting of magnesium and a capillary movement. The density, Tc and Jc results suggest that the current carrying capacity can be improved by a careful control of the process parameters regarding a pore evolution.",

keywords = "In situ process, MgB superconductor, Pore formation, Reaction",

author = "Yi, \{J. H.\} and Kim, \{K. T.\} and Jun, \{B. H.\} and Sohn, \{J. M.\} and Kim, \{B. G.\} and J. Joo and Kim, \{C. J.\}",

year = "2009",

month = oct,

day = "15",

doi = "10.1016/j.physc.2009.05.190",

language = "English",

volume = "469",

pages = "1192--1195",

journal = "Physica C: Superconductivity and its Applications",

issn = "0921-4534",

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TY - JOUR

T1 - Pore formation in in situ processed MgB2 superconductors

AU - Yi, J. H.

AU - Kim, K. T.

AU - Jun, B. H.

AU - Sohn, J. M.

AU - Kim, B. G.

AU - Joo, J.

AU - Kim, C. J.

PY - 2009/10/15

Y1 - 2009/10/15

N2 - MgB2 bulks were prepared by an in situ process which utilizes the reaction between boron and magnesium powder. The reaction time was fixed at 0.5 h and the temperature was changed from 600 °C to 1000 °C. The density decrease due to pore formation and mass (mainly magnesium) loss during the formation reaction of MgB2 was observed in all samples. In addition to the pore formation, a pellet expansion which can be explained by the outgrowth of MgB2 grains was also observed. Two different mechanisms were adopted to explain the pore formation; Kirkendall pores formed at a temperature below the melting point (m.p.) of magnesium by a difference in the diffusivity between magnesium and boron, and the pores formed at a temperature above the m.p. by melting of magnesium and a capillary movement. The density, Tc and Jc results suggest that the current carrying capacity can be improved by a careful control of the process parameters regarding a pore evolution.

AB - MgB2 bulks were prepared by an in situ process which utilizes the reaction between boron and magnesium powder. The reaction time was fixed at 0.5 h and the temperature was changed from 600 °C to 1000 °C. The density decrease due to pore formation and mass (mainly magnesium) loss during the formation reaction of MgB2 was observed in all samples. In addition to the pore formation, a pellet expansion which can be explained by the outgrowth of MgB2 grains was also observed. Two different mechanisms were adopted to explain the pore formation; Kirkendall pores formed at a temperature below the melting point (m.p.) of magnesium by a difference in the diffusivity between magnesium and boron, and the pores formed at a temperature above the m.p. by melting of magnesium and a capillary movement. The density, Tc and Jc results suggest that the current carrying capacity can be improved by a careful control of the process parameters regarding a pore evolution.

KW - In situ process

KW - MgB superconductor

KW - Pore formation

KW - Reaction

UR - https://www.scopus.com/pages/publications/68149087570

U2 - 10.1016/j.physc.2009.05.190

DO - 10.1016/j.physc.2009.05.190

M3 - Article

AN - SCOPUS:68149087570

SN - 0921-4534

VL - 469

SP - 1192

EP - 1195

JO - Physica C: Superconductivity and its Applications

JF - Physica C: Superconductivity and its Applications

IS - 15-20

ER -

Pore formation in in situ processed MgB₂ superconductors

Abstract

Keywords

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