TY - JOUR
T1 - Effect of high-energy ball milling time on superconducting properties of MgB 2 with low purity boron powder
AU - Wang, Chengduo
AU - Ma, Yanwei
AU - Zhang, Xianping
AU - Wang, Dongliang
AU - Gao, Zhaoshun
AU - Yao, Chao
AU - Wang, Chunlei
AU - Oguro, Hidetoshi
AU - Awaji, Satoshi
AU - Watanabe, Kazuo
PY - 2012/3
Y1 - 2012/3
N2 - MgB 2 bulks and tapes were fabricated using ball-milled precursor powders. The selected B powders have the -rhombohedral crystalline structure as a main phase, with a small amount of MgO impurity. Milling time was tested from 0.5 to 120h to get an optimized value. It is found that ball milling can facilitate MgB 2 phase formation, refine the MgB 2 grains and increase the defect density. Moreover, the active area, B c2 and flux pinning are improved, which is of benefit to the enhancement of J c performance. The 80 h milled MgB 2 bulk sample has a J c value of 2.8×10 4Acm 2 at 5K and 6T, 41 times larger than that of the 0.5h sample. At the same time, the transport J c of the 80h MgB 2 tape reaches 2.3×10 3Acm 2 at 4.2K and 9T, 32 times larger than that of the 0.5h one. Due to the increase of impurities and the release of lattice deformation and strain, the J c was decreased for the sample milled up to 120h.
AB - MgB 2 bulks and tapes were fabricated using ball-milled precursor powders. The selected B powders have the -rhombohedral crystalline structure as a main phase, with a small amount of MgO impurity. Milling time was tested from 0.5 to 120h to get an optimized value. It is found that ball milling can facilitate MgB 2 phase formation, refine the MgB 2 grains and increase the defect density. Moreover, the active area, B c2 and flux pinning are improved, which is of benefit to the enhancement of J c performance. The 80 h milled MgB 2 bulk sample has a J c value of 2.8×10 4Acm 2 at 5K and 6T, 41 times larger than that of the 0.5h sample. At the same time, the transport J c of the 80h MgB 2 tape reaches 2.3×10 3Acm 2 at 4.2K and 9T, 32 times larger than that of the 0.5h one. Due to the increase of impurities and the release of lattice deformation and strain, the J c was decreased for the sample milled up to 120h.
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U2 - 10.1088/0953-2048/25/3/035018
DO - 10.1088/0953-2048/25/3/035018
M3 - Article
AN - SCOPUS:84863169470
SN - 0953-2048
VL - 25
JO - Superconductor Science and Technology
JF - Superconductor Science and Technology
IS - 3
M1 - 035018
ER -