• 제목/요약/키워드: Bi-2223/Ag HTS

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기지금속을 달리한 Bi-2223 초전도 선에서의 기계적 특성 변화 (Mechanical properties at Bi-2223 HTS tapes with various sheath materials)

  • 하동우;이동훈;양주생;김상철;황선역;하홍수;오상수
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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    • pp.551-554
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    • 2004
  • Bi-2223 HTS tapes are used widely for application of superconducting power systems. However there are need the properties of high strength and low AC loss. Two kinds of Bi-2223 HTS tapes with different Ag sheath were used to know the effect of sheath alloying for the strength and the resistivity. The workability and reaction degree of superconducting phase at Bi-2223 HTS tapes were investigated. We designed conventional type-Ag/alloy and double sheathed mono filament type-Ag/alloy/alloy in order to increase the strength and resistivity of matrix in Bi-2223 HTS tapes. The effect of axial strain and thermal cycling on the critical current was investigated for the Bi-2223 HTS tapes. Because the workability of double sheath Bi-2223 HTS tape was lower than one sheath Bi-2223 HTS tape, it was need additional softening treatment. Bi-2223 formation reaction was decreased by Ag alloy matrix during sintering process. Two kinds of Bi-2223/Ag tapes with different Ag sheath were used to know the effect of sheath alloying for the tensile strain. Critical current is drastically decreased for Ag/alloy and Ag/alloy/alloy sheathed tapes at tensile strain above 0.24 % and 0.34 %, respectively. This result showed that mechanical strength was increased over than 40 % by introduce double sheath at mono filament stage.

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Bi-2223/Ag 고온초전도 선재의 기계적 특성 평가 (Evaluation of mechanical properties of Bi-2223/Ag HTS tapes)

  • 하홍수;이동훈;양주생;최정규;윤진국;하동우;오상수;권영길
    • 한국초전도저온공학회:학술대회논문집
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    • 한국초전도저온공학회 2002년도 학술대회 논문집
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    • pp.351-354
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    • 2002
  • In most of electrical applications using Bi-2223/Ag HTS tapes, bending and tension stresses are essentially applied to the tape. Therefore, the critical current of the Bi-2223/Ag tape is degraded by increasing the deformation stress, though brittle superconducting filaments are embedded in the reinforced Ag alloy sheath. It is needed to understand bending and tension properties of HTS tapes at room temperature and cryogen to make superconducting magnet, cable and etc. using Bi-2223/Ag HTS tapes. Actually, bending and tension stress applied to the tapes simultaneously, when winding the tapes on former for applications. In this study, the effect of mechanical deformations, bending and tension, on the critical current of Bi-2223/Ag tape was investigated.

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Bi-2223/Ag 데이프 및 Protype HTS 케이블의 상전도 영역전파 특성 (Normal Zone Propagation Properties of Bi-2223/Ag Tape and Prototype HTS Cable)

  • 김상현;이병성;김영석;장현만;백승명;한철수
    • 한국전기전자재료학회논문지
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    • 제14권4호
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    • pp.345-350
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    • 2001
  • Normal zone propagaton(NZP) properties were investigated on Bi-223/Ag tapes and prototype HTS cable. NZP experiments in tape were conducted in temperatures from 45K to 77K in zero field. Prototype HTS cable was molded using epoxy and the experiments were carried out under adiabatic condition in LN$_2$. NZP velocities in tapes with tow conditions of DC and AC currents were almost same at each temperature. NZP velocity in prototype HTS cable was 1.9-2.4 cm/sec in LN$_2$. Numerical analysis was carried out by a one-dimensional equation of heat balance. The simulation results of NZP velocity in Bi-2223/Ag tapes were similar to the experimental results.

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Bi-2223/Ag 고온초전도 선재의 기계적 특성 평가 (Evaluation of mechanical properties of Bi-2223/Ag HTS tapes)

  • 하홍수;이동훈;양주생;최정규;윤진국;하동우;오상수;권영길;김상철
    • 한국초전도ㆍ저온공학회논문지
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    • 제4권1호
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    • pp.45-59
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    • 2002
  • Evaluation of the mechanical properties of Bi-2223/Ag HTS tapes was carried out by the tension and bending tests. Most of the Bi-2223/Ag tapes retained critical current up to 10 kgf/mm$_2$ axial tension stress, and 0.2% tension strain at room temperature. Applied tension strain exceeding 0.3% in superconducting tapes at 77 K leaded to rapid degradation of the critical current. It was observed that the more filaments, the better axial tension property at 77 K, self-field The influence of bending strain on critical current degradation was revealed to be less sensitive for Bi-2223/Ag HTS tapes with a more number of filaments and higher silver ratio.

조성이 다른 전구체 분말에 따른 Bi-2223/Ag 초전도 테이프의 특성 변화 (Properties of Bi-2223/Ag HTS tapes using different content of precursors)

  • 하동우;양주생;하홍수;오상수;황선역;이동훈;최정규;이언용;권영길
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2003년도 춘계학술대회 논문집 초전도 자성체 연구회
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    • pp.69-72
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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. XRD and DC magnetization analysis were performed in order to investigate the fraction of Bi-2223 phase in Bi-2223/Ag HTS tape. 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. DC magnetization analysis was useful to investigate the fraction of Bi-2223 phase in the Bi-2223/Ag tape.

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열처리 온도 및 분위기 변화에 따른 Bi-2223 초전도 선재에서의 특성변화 (superconducting properties of Bi-2223 tapes with various heat treatment condition)

  • 하동우;이동훈;하홍수;오상수;김홍대;양주생;윤진국;최정규;권영길
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2002년도 하계학술대회 논문집
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    • pp.527-530
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    • 2002
  • A lot of efforts have been focused on the optimization of PIT parameters for Bi-2223/Ag wire. In this paper, initial annealing of Bi-2223/Ag wire to transform Bi-2212 orthorhombic from Bi-2212 tetragonal Precursor was investigated. This initial annealing step at low oxygen partial pressure were to transform Bi-2212 orthorhombic structure and to reduce the formation of second phases at superconducting wire. However Bi-2223 Phases were appeared at higher annealing temperature. Critical currents(Je) of Bi-2223/Ag tapes were sintered at low oxygen Partial pressure were higher than that of the wires sintered at atmosphere condition. In order to investigate the effect of rolling reduction ratio, Bi-2223/Ag HTS tapes were rolled with different reduction ratio. There were no clear difference of Je and filaments shape with various rolling reduction ratio.

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Bi-2223/Ag 고온초전도선재의 가공균일성에 미치는 인발공정연구 I (Bi-2223/Ag HTS Drawing Process Study for Uniform Deformation I)

  • 김상철;하홍수;오상수;이동훈;양주생;하동우;권영길;한일용;이종건
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2002년도 춘계학술대회 논문집 초전도 자성체
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    • pp.55-58
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    • 2002
  • PIT method which is used at fabricating Bi-2223/Ag HTS wire includes a drawing process, conventional deformation method. Drawing of meta1(Ag) and ceramic (BiSrCaCuO) composite is also difficult and significant for uniform deformation. In this paper, parameters of uniform deformation was studied at Bi-2223/ Ag multifilamentary HTS wire. Powder and rod as a starting precursor was compared at 55 filament and 54 filament Bi-2223/Ag HTS wire, respectively. Micro-hardness and area COV of the filaments was also evaluated when the diameters were decreased through drawing operations.

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Bi-2223/Ag 고온초전도 장선재의 제조 (Fabrication of long length Bi-2223/Ag HTS tape)

  • 김상철;이동훈;하동우;오상수
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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    • pp.69-72
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    • 2004
  • In order to use HTS tape on electric power applications, such as cable, motor, transformer, fault current limiter, a long length of HTS tape with a good uniformity of critical current is inevitable. The longer length of HTS tape, the wider in the range of application and the lower cost of HTS tape. In this study three long length Bi-2223/Ag tapes(268m, 253m and 187m) were fabricated. Critical current uniformity along the length was greatly improved through the optimization of cold deformation and thermo-mechanical process. Average critical current of the tapes was 63.2 A, 54.6 A and 64.2 A, respectively Critical tensile strength and critical bending radius (77 K, 5 % Ic degradation) was 135 MPa and 56 m, respectively.

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

  • 하동우;양주생;황선역;하홍수;오상수;이언용;권영길
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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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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Bi-2223/Ag HTS 장선재의 Ic 특성 향상 공정 연구 (Study on fabrication process of long length of Bi-2223/Ag MTS wires for high critical current)

  • 하동우;양주생;황선역;이동훈;최정규;하홍수;오상수;권영길
    • 한국초전도저온공학회:학술대회논문집
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    • 한국초전도저온공학회 2003년도 학술대회 논문집
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    • pp.105-108
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    • 2003
  • Long length of Bi-2223 superconducting wires were fabricated by stacking, drawing process with different precursor owders 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. We designed and made a continuous Ic measurement system for Bi-2223/Ag HTS tape. We could achieve best Ic of 65 A at the Bi-2223/Ag tape using low Pb content of precursor powder and experienced pre-annealing process.

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