• Title/Summary/Keyword: Bi-2212/Ag

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A study on the Joining Properties of Bi-2212 High-Tc Superconducting Tube and Indium Solder (Bi-2212 고온초전도튜브와 인듐솔더의 접합특성연구)

  • Oh, S.Y.;Hyun, O.B.;Kim, Chan-Joong
    • Progress in Superconductivity
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    • v.7 no.2
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    • pp.179-183
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    • 2006
  • As a material for SFCL(Superconducting Fault Current Limiter), BSCCO tube with metal stabilizer is a promising candidate, assuring the stability and large power capacity, For the application, the proper soldering technique, which overcome the difficulties of the joining between BSCCO and metal stabilizer, is required. In this study, after soldering In-Bi solder and In-Sn solder with BSCCO superconductor, welding properties between BSCCO and solders were investigated. Because ceramic materials is difficult to weld, Ag electro-plating on BSCCO 2212 is used for intermetallic layer. To find out the best welding condition for superconductor, soldering is tested in the maximum temperature from $155^{\circ}C\;to\;165^{\circ}C$ in the reflow oven. By investigating the composition and thickness of IMC (lntermetallic Compound) created in the reaction of Ag with solder, we analyzed the welding properties of High-Tc superconductor from a micro point of view.

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Effect of the Ag Additive on the ${Bi_{1.84}}{Pb_{0.34}}{Sr_{1.91}}{Ca_{2.03}}{Cu_{3.06}}{O_{10+\delta}}$(110K Phase) High-$T_{c}$ Susperconductor (${Bi_{1.84}}{Pb_{0.34}}{Sr_{1.91}}{Ca_{2.03}}{Cu_{3.06}}{O_{10+\delta}}$(110K 상) 산화물 고온초전도체에 미치는 Ag 혼합효과)

  • 이민수;최봉수;최봉수
    • Journal of the Korean Ceramic Society
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    • v.38 no.12
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    • pp.1104-1109
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    • 2001
  • Samples with the nominal composition, B $i_{1.84}$P $b_{0.34}$S $r_{1.91}$C $a_{2.03}$C $u_{3.06}$ $O_{10+}$$\delta$/ high $T_{c}$ superconductors containing As as an additive were fabricated by a solid-state reaction method. Samples with Ag of 10wt%, 30 wt% and 50 wt% each were sintered at 86$0^{\circ}C$~875$^{\circ}C$ for 24 hours. The structural characteristics, critical temperature and grain size with respect to Ag contents were analyzed by XRD(X-ray Diffraction) and SEM(Scanning Electron Microscope), respectively. As Ag contents increased, XRD peaks of g in Bi-2223 phase superconductors intensified and the proportion of the phase transition from Bi-2223 to Bi-2212 was increased.increased.

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Properties of Bi-2223/Ag HTS tapes prepared using powders of varying lead content (Pb 함량을 달리한 전구체 분말에서의 Bi-2223/Ag 초전도 테이프의 특성 변화)

  • Ha, Dong-Woo;Yang, Joo-Saeng;Hwang, Sun-Yuk;Ha, Hong-Soo;Oh, Sang-Soo;Lee, En-Yong;Kwon, Young-Kil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07a
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    • pp.585-588
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    • 2003
  • Bi-2223 superconducting wires were fabricated by stacking, drawing process with different precursor powders and different heat-treatment histories. The precursor powders were 2 kinds of Pb content. And a part of the tapes were experienced pre-annealing process which caused tetragonal structure of Bi-2212 phase to orthorhombic structure of it was during drawing process. We confirmed the transformation of Bi-2212 phase from tetragonal structure to orthorhombic structure and reduction of second phases. AC magnetization analysis were performed in order to investigate the fraction of Bi-2223 phase in Bi-2223/Ag HTS tape. The cross sections of 55 filaments and 61 filaments were investigated after rolled in order to understand deformation mechanism of superconducting cores. We could achieve best Ic of 70 A class at the Bi-2223/Ag tape using low Pb content of precursor powder and experienced pre-annealing process. AC magnetization analysis was useful to investigate the fraction of Bi-2223 phase in the Bi-2223/Ag tape.

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Superconducting properties of Bi-2223 tapes with various pre-annealing conditions (전열처리 조건에 따른 Bi-2223 초전도 선재에서의 특성 변화)

  • 하동우;하홍수;오상수;이동훈;윤진국;양주생;최정규;권영길
    • Progress in Superconductivity
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    • v.4 no.2
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    • pp.176-179
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    • 2003
  • A lot of efforts have been focused on the optimization of PIT parameters for Bi-2223/Ag wire. Bi-2223 superconducting wires with 55 filaments were fabricated by stacking, drawing process. Before rolling process, round wires were pre -annealed at 760 - 820 $^{\circ}C$ and low oxygen partial pressure. We confirmed that pre-annealing step was to transform Bi-2212 orthorhombic structure from Bi-2212 tetragonal structure and to reduce the formation of second phases. However Bi-2223 phases also were formed at higher than 76$0^{\circ}C$ of pre-annealing temperature. The engineering critical current densities (Je) of Bi-22231Ag tapes were sintered at low oxygen partial pressure were higher than t hat of the wires sintered at air. We could achieve 6500 A/${cm}^2$ of Je for the tape that was initially kept at slightly higher temperature than that of normal heat treatment.

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Study on commercialization process of Bi-B223 HTS tape (Bi-2223 고온초전도 선의 상용화 공정 연구)

  • 하동우;김상철;오상수;하홍수;이동훈;양주생;황선역
    • Progress in Superconductivity and Cryogenics
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    • v.6 no.1
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    • pp.1-5
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    • 2004
  • Long length of Bi-2223/Ag superconducting wives were fabricated by stacking and drawing process with advanced heat-treatment schedules. Intermediate annealing was carried out to increase the homogeneity and uniformity of the superconducting filaments embedded in the silver matrix. Phase modification from tetragonal to orthorhombic Bi-2212 by pre heat treatment(PHT) was executed to improve the texture and phase transformation of Bi-2223. Drawing stress was measured to predict the sausaging and stress limit. Rolling Parameters such as thickness. width and winding tension were investigated to roll the tape with uniformity. 1 km length of Bi-2223/Ag superconducting wires were fabricated without any breakage. Critical current (Je) of 270 m length of superconducting tapes was measured over than $70 A/cm^2$ continuously after final sintering.

Raman-tensor analysis of phonon modes in (Pb, Bi)2Sr2CaCu2O8+δ

  • Ji Yoon Hwang;Sae Gyeol Jung;Dong Joon Song;Changyoung Kim;Seung Ryong Park
    • Progress in Superconductivity and Cryogenics
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    • v.26 no.1
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    • pp.10-13
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    • 2024
  • We performed angle-resolved Raman spectroscopy experiments on lead-doped and undoped Bi2Sr2CaCu2O8+δ(Bi2212) samples using a 660 nm laser and analyzed the Raman tensor of the phonon modes. The phonon mode was clearly observed at the 60, 103, and 630 cm-1 Raman shifts. The 60, 630 cm-1 peaks were only clearly observed when the incident and scattered light polarizations were configured to be parallel. The polarization angle dependence of the amplitude of the 60, 630 cm-1 peak on the parallel configuration shows a twofold symmetry; therefore, both peaks originate from Ag phonons and the crystal structure of Bi2212 should be considered orthorhombic. On the other hand, the 103 cm-1 peak is clearly observed in both parallel and perpendicular configurations. Remarkably, the off-diagonal component of the Raman tensor of the 103 cm-1 peak showed an anti-symmetry that could not be realized within the known crystal structure of Bi2212. The implications of our findings are discussed.

Development of km class Bi-2223/Ag HTS tapes (1km급 Bi-2223/Ag 고온초전도 선재 개발 연구)

  • 하동우;오상수;김상철;양주생;황선역;이동훈;최종규;하홍수;권영길
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2003.10a
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    • pp.63-66
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    • 2003
  • 1 km length of Bi-2223/Ag superconducting wires were fabricated by stacking, drawing process with advanced heat-treatment schedules. Intermediate annealing was carried out to increase the homogeneity and uniformity of the superconducting filaments embedded in the silver matrix. Phase modification from tetragonal to orthorhombic Bi-2212 by pre heat treatment(PHT) was executed to improve the texture and phase transformation of Bi-2223. Drawing stress was measured to Predict the sausaging and stress limit, Rolling parameters such as thickness, width and winding tension were investigated to roll the tape with uniformity. Critical current of 1 km length of superconducting tapes was measured about 50 A continuously after final sintering.

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