한국초전도학회:학술대회논문집

The Korean Superconductivity Society (한국초전도학회)
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Formation of the precipitates in the Bi-2223/Ag superconducting tapes by post-heat treatment

Bi-2223 초전도 선재의 후열처리 과정에 의한 석출물의 형성

  • Lee, Sang-Hee (Dept. of Inorganic Materials Eng., Advanced Materials Research Institute, Gyeongsang National University) ;
  • Kim, Cheol-Jin (Dept. of Inorganic Materials Eng., Advanced Materials Research Institute, Gyeongsang National University) ;
  • Chung, Jun-Ki (Dept. of Inorganic Materials Eng., Advanced Materials Research Institute, Gyeongsang National University) ;
  • Yoo, Jae-Moo (Korea Institute of Machinery & Metals) ;
  • Ko, Jae-Woong (Korea Institute of Machinery & Metals)
  • Published : 2000.08.16
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Abstract

To tap the possibility of exploiting the precipitates as flux-pinning center in the Bi-2223 superconducting system, as-received Bi-2223/Ag tapes with the starting composition of Bi$_{1.8}$Pb$_{0.4}$Sr$_2$Ca$_{2.2}$Cu$_3$O$_8$ were post-annealed at various temperature, oxygen partial pressure, and annealing time. The 2$^{nd}$ phases in the annealed specimen were analysed with XRD, SEM, TEM, and EDS. The size and the distribution of the precipitates such as (Ca,Sr)$_2$(Pb,Bi)O$_4$ and Bi$_{0.5}$Pb$_3$Sr$_2$Ca$_2$CuO$_{12+{\delta}}$ (3221) in the Bi-2223 matrix was controllable by varying heat-treatment condition without breaking the connectivity of the 2223 grains. The nano-size precipitates within the 2223 grains are conjectured as working as flux-pinning sites, resulting in increased J$_c$ value.

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