• 제목/요약/키워드: BSCCO 2223

검색결과 99건 처리시간 0.028초

BSCCO 초전도 선재의 미세조직 및 임계전류밀도에 미치는 공정변수 효과 (Effect of Processing Variables on Microstructure and Critical Current Density of BSCCO Superconductors Tape)

  • 지봉기;김태우;주진호;김원주;이희균;홍계원
    • 한국전기전자재료학회논문지
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    • 제11권11호
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    • pp.1014-1021
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    • 1998
  • We evaluated the effect of processing variables on microstructural evolution interface irregularity between Ag sheath and superconductor core and resultant critical current density(J$_{c}$) of (Bi,Pb)$_2$Sr$_2$Ca$_2$Cu$_3$O$_{x}$(2223) superconductor tape. The value of J$_{c}$ was significantly influenced by the interface irregularity, degree of texturing and relative 2223 content. The interface became more irregular(sausage effect), while the degree of texturing gradually improved as the dimension of tape decreased during forming process. As the dimension of wire/tape were changed from diameter of 3.25 mm to thickness of 0.20 mm, J$_{c}$ value was observed to be increased by 10 times. In addition, optimum sintering temperature for improved J$_{c}$ was observed to be 835$^{\circ}C$ in a ambient atmosphere probably due to combined effect of both improved texturing and high 2223 content. Microstructural investigation showed the degree of texturing was degraded by the existence of both second phases and interface irregularity. It was observed that larger grain size and better texturing was developed near relatively flat interface compared to those inside superconducting core.ting core.

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61심 BSCCO 2223 고온초전도 선재의 접합부 제조 (Fabrication of Superconducting Joints between 61 Filaments of BSCCO 2223 Tapes)

  • 김철진;박성창;유재무
    • 한국세라믹학회지
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    • 제35권2호
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    • pp.137-144
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    • 1998
  • 고온초전도체 61심 Bi-2223 선재간의 초전도 접합부위를 화학적 부식 및 열적· 기계적 반복 공정에 의하여 제조하였다. 초전도 선재 테이프의 은 피복재 한쪽 표면을 초전도체와 반응하지 않는 부식액(NH4OH:H2O2=1:1)으로 화학적으로 제거한 다음, 두 시편을 일출가압 성형하여 접합시편을 제조하였고 일련의 서로 다른 열적· 기계적 처리를 거쳐 접합부의 물성 및 미세구조를 분석하였다. 접합부를 따라 임계전류(Ic) 변화와 전류전압 곡선의 특성을 측정하기 위하여 여러 단자를 접합부 주위에 설치하여 부위별 I~V 특성을 측정한 결과 단심선재에 비하여 다심선재에서 선재 전체의 통전 능력을 좌우하는 천이구간의 임계전류값이 높았다. 그러나 단심에 비해 다심선재는 천이급속도를 나타내는 n값이 다심선재내 각각의 초전도 core들의 상호작용에 의하여 낮은 값을 나타내었다. 접합부의 임계전류 통전성은 반복적인 가압성형 공정과 서냉반응 열처리 공정에 의하여 향상되었다.

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고온초전도 BSCCO 2223 선재간의 초전도 접합부 제조연구 (Fabrication of superconducting Joints Between PIT Processed BSCCO 2223 Tapes by Single and Multiple Press & reaction Annealing)

  • 유재무;고재웅;정형식
    • 연구논문집
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    • 통권27호
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    • pp.175-181
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    • 1997
  • Superconducting joints between Bi-2223/Ag tapes are fabricated by a press & reaction anneal and a multiple press & anneal. The silver sheath was mechanically or chemically removed from one side of each tape without altering the superconducting core. The exposed superconducting core of the two tapes were brought into contact and pressed so as to form a lap joint. The joined tapes were then subjected to a series of different thermomechanical treatments to achieve optimum heat treatment condition. The result from transport measurements shows that critical current ($I_c$) transmitting through joined area reaches 9A, approximately 60% of the current capacity of the tapes themselves. The critical current through joined area was improved by repeated press and reaction annealing. Measurements of the current-voltage relationship were made with several configuration of the voltage probes to characterize the critical current variation and I-V curve along the joint. Also discussed are microstructural aspects of the superconducting joint.

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BSCCO 고온초전도 전류도입선의 제조 (Fabrication of BSCCO high-Tc superconducting current lead)

  • 하동우;오상수;류강식;장현만
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1996년도 춘계학술대회 논문집
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    • pp.252-255
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    • 1996
  • Superconducting current lead is one of the promising applications of the oxide high-Tc superconductors, because they have the advantage of decreasing heat conduction to low temperature region, comparing with a conventional cooper alloy lead. High critical current density is a key factor for the applications such as current lead. (Bi,Pb)$_2$Sr$_2$Ca$_2$Cu$_3$O$\_$x/ high Tc superconductor haute been investigated in terms of critical current density. Bi-2223 superconducting current lead made by CIP and solid state sintering process. Bi-2223 current lead that heat treated at 836$^{\circ}C$ for 240 h in 1/13 P$\_$O$_2$/ had over 150 A/$\textrm{cm}^2$ of critical current density at 77K. We knew that the superconducting properties of tube type current leads were better than rods type of them. And we investigated the relation of Bi-2223 formation and heat treatment condition by XRD and SEM analysis.

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BSCCO 고온초전도선재를 이용한 고온초전도전원장치의 동작특성 해석 (Analysis of the Operational Characteristics of High-Tc Superconducting Power Supply Using by BSCCO Tape)

  • 안민철;김호민;윤용수;고태국;이상진;한태수
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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    • pp.12-14
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    • 2001
  • This paper deals with the fabrication and characteristic experiment of a high-Tc superconducting (HTSC) power supply using by Hi-2223 tape. The purpose of this research is to apply real HTSC load. This system consists of two heaters, an electromagnet, a Bi-2223 solenoid and a Bi-2223 pancake load. In the experiment, 17sec and 8.5sec were used for pumping period. Mechanism of the superconducting switch is used for heater-trigger. In experiment, the pumping-current has reached about 1.2A.

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BSCCO(2223) 초전도 선재의 접합공정 연구 (A Study of Joining Method of BSCCO(2223) Tape)

  • 김정호;김중석;김태우;지붕기;주진호;나완수
    • 한국초전도ㆍ저온공학회논문지
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    • 제1권2호
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    • pp.1-7
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    • 1999
  • we evaluated the effects of joining process such as contact method. shape of joined area and pressure on the electrical and mechanical properties of Bi-2223 superconducting tape, Specifically. the current capacity of the jointed tape was measured as a function of uniaxial pressure. and the thermal shock, bonding strength and the thermal of the tape were evaluated and correlated to the microstructural evolution. It was observed that the current capacity was significanrly dependent on the uniaxial pressure The jointed tape, fabricated with a pressure of 1,000-1,600 Mpa. showed the highest value of current capacity results from improvements in core density, contacting area and grain alignment, ect. In addition, the strength of jointed tape was measured to be 86 Mpa, which is about 88% of the unjoined ape's strength. The irreversible strain($\varepsilon$irrev) for the jointed tape was measured to be 0.1%, smaller than that of unjoined tape ($\varepsilon$irrev= 0.3%). The decrease in the strength and irreversible strain for jointed tape is believed to be due to the irregular geometry/morphology of the transition area of the tape.

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Bi2223 초전도후막의 전기영동전착 특성 (Electrophoretic deposition of Bi2223 Superconductor Thick Film)

  • 전용우;소대화;최성재;박정철
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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    • pp.97-100
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    • 2004
  • In this paper, the preparation of BSCCO superconducting wire by electrophoretic deposition method and the effect of suspension medium used with various solvent solutions of ethanol and buthanol for electrophoretic deposition were studied. The preheating technique in vacuum system for the superconducting powders coated on Ag wire was also investigated. As a result, it was confirmed that the preheating technique was very useful to remove the influence of remains affected to the surface conditions of superconducting wire. And the adsorbed solvent solution which was existed between and on the deposited particle surfaces was almost disappeared at the treating conditions of about $10^{-3}$ Torr and around $200^{\circ}C$ in bell-jar system. By measurement of 4-point prove method, the critical current density($J_c$) of BSCCO superconducting wire was obtained at the value of more than $10^4\;A/cm^2$ in liquid $N_2$(77 K, 0 T).

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37심 BSCCO(2223) 다심 초전도선재의 접합공정 연구 (Fabrication of Joining of 37 Multi-filamentary BSCCO(2223) Tape)

  • 김정호;오승진;김규태;김호진;주진호;나완수
    • 한국초전도저온공학회:학술대회논문집
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    • 한국초전도저온공학회 2001년도 학술대회 논문집
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    • pp.3-5
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    • 2001
  • We evaluated the electrical properties of 37 multifilamentary jointed tapes processed by superconducting joint. In the superconducting joining method. a lap-joint was used. Tapes were selectively etched and exposed superconducting cores of the two tapes were brought into contact with each other and then only the joined region was uniaxially pressed in the range of 1,000 to 2,500 MPa. The current carrying capacity and n-value of the jointed tape were evaluated as a function of uniaxial pressure. The highest current carrying capacity and n-value were obtained to be 58%, 26% for the jointed tape to the tape itself.

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The application of hydrated fine MgO particles for flux pinning center in the HTS-BSCCO system

  • 김성환;김철진;정준기;박성창;유재무
    • Progress in Superconductivity
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    • 제3권2호
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    • pp.188-192
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    • 2002
  • To introduce flux pinning center in HTS-BSCCO system, nano-size MgO particles were uniformly distributed within the Bi-2223 grain by partial hydration of MgO. The existing method MgO doped Bi-2223 used nato-size MgO powders, which resulted in agglomeration during mixing or grain growth during heat-treatment due to the high surface energy of the fine particles. By hydration of the MgO surface, the agglomeration of the MgO powders was avoided and the size of remaining MgO core was controlled by changing hydration medium and time. The thin film obtained by spin coating of (Bi_$1.8/Pb_{0.4}$)$Sr_2$$_{Ca}$$2.2/Cu_3$ $O_{y}$ nitrate solution mixed with hydrated MgO showed the even distribution of nano-size MgO particles in the Bi-2212 grains.s.s.

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