• Title/Summary/Keyword: BSCCO tape

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Fabrication of fine BSCCO-2223 precursor powder by spray pyrolysis process (분무 열분해방법에 의한 미세 BSCCO-2223 전구분말의 제조)

  • 김성환;유재무;고재웅;김영국;박기호
    • Progress in Superconductivity
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    • v.5 no.1
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    • pp.65-69
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    • 2003
  • Many researches on fabrication process for BSCCO precursor powders have been developed for high J$_{c}$ BSCCO-2223 tape. Spray pyrolysis method for fabrication of precursor powder has many advantages, such as high purity, fine particle size and low carbon content of BSCCO precursor powder. Fine, spherical powders were prepared by ultrasonic spray pyrolysis from the aqueous solution of metal nitrates. BSCCO precursor powders were synthesized with various solutes concentration and heat treatment conditions. Average particle size for spray pyrolysis powders was $1.5∼3\mu\textrm{m}$. Bi-2223/Ag tape was prepared by PIT method and followed by various sintering conditions. BSCCO precursor powders were characterized by XRD, SEM, EDS, Carbon content and particle size analysis.s.

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BSCCO 초전도선재의 twisting 공정연구

  • Im, Jun-Hyeong;Ji, Bong-Gi;Park, Hyeong-Sang;Ju, Jin-Ho;Jang, Mi-Hye;Go, Tae-Guk;Ha, Hong-Su;O, Sang-Su
    • 한국초전도학회:학술대회논문집
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    • v.10
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    • pp.221-225
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    • 2000
  • The effect of twisting on the microstructural evolution and critical current of BSCCO superconductor tape has been evaluated. Twisting pitches of the tapes are in the range of 8-70 mm and uniformly deformed. The critical current of twisted tape was dependent on the twist pitch. Specifically, it was observed that the critical current decreased with decreasing twist pitch, and only 50% of critical current was retained when the tape was twisted to a pitch of 8 mm. This reduction of the critical current may be related to the interface irregularity, smaller grain size, worse texture and the presence of cracks due to the induced strain during the twisting processing.

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A Study of fabrication and microstructural evolution of twisted BSCCO superconductor tape (Twisting된 BSCCO 선재 제조 및 미세조직 연구)

  • 임준형;지봉기;박형상;주진호;장미혜;고태국;이상진;하홍수;오상수
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2000.02a
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    • pp.112-114
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    • 2000
  • We fabricated BSCCO multifilaments superconductor tape and evaluated the effect of twisting on the microstructural evolution and critical current. Twist pitches of the tapes are in the range of 70 - 8 mm and uniformly deformed. It was observed that grain size and the degree of texture decreased as decreasing pith, probably due to the formation of the irregular interface between Ag and filaments. In addition, critical current of the tapes decreased to 6.5A with decreasing pitch to 8 mm, showing 48% of degradation compared to the untwisted tape(12.5 A). These reduction of critical current may be related to the interface irregularity, smaller grain size, worse texture and the presence of cracks due to the induced strain during twisting processing.

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

  • 김정호;김중석;김태우;지붕기;주진호;나완수
    • Progress in Superconductivity and Cryogenics
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    • v.1 no.2
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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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Superconducting Joint of Multi-filament BSCCO(2223) Tapes by using Single-filament Tape (BSCCO(2223) 단심 초전도 선재를 이용한 다심 초전도 선재의 접합공정 연구)

  • 김규태;김정호;장석헌;주진호;강형구;고태국;하홍수;오상수
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.10
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    • pp.923-930
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    • 2003
  • We jointed Bi(Pb)-Sr-Ca-Cu-O multifilament tapes and evaluated their electrical and mechanical properties. In order to improve connectivity of multifilaments, one or two single-filament tape was inserted between two multifilament tapes. The critical current ratio(CCR) and n-value of the jointed tapes were evaluated as a function of uniaxial pressure. It was observed that critical current ratio and n-value were 24.8-29.0% and 2.5-2.8 for MM lap-jointed tape. On the other hand, the corresponding values were improved to 24.7-53.9% and 3.1-4.2 for MSM jointed tape, and 63.4-76.0% and 3.4-5.1 for double MS:vr lap-jointed tape, respectively. The highest electrical properties of double MSM lap-jointed tape are considered to be owing to the presence of single core, causing better interconnections of multifilaments between the two tapes. The mechanical property of jointed tape was evaluated and correlated to the microstructural evolution. The strength of jointed tapes was 44-64% less than that of the unjoined tape. The strain tolerance of jointed tape was also reduced compared to that of the unjoined tape. These lower mechanical properties of jointed tape are probably due to the induced nonuniform microstructure such as the existence of cracks and Ag-intrusion in the joined region.

A Study of Joint Characteristic of BSCCO Superconductor Tape (BSCCO 고온초전도 선재의 접합특성 연구)

  • Kim, Jung-Ho;Kim, Joong-Seok;Kim, Tae-Woo;Ji, Bong-Ki;Joo, Jin-Ho;Nah, Wan-Soo
    • 한국초전도학회:학술대회논문집
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    • v.9
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    • pp.378-382
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    • 1999
  • We evaluated the effect of joining process such as contact method, shape of joined area and pressure on the electrical property of Bi-2223 superconducting tape. It was observed that the current capacity was reduced at the transition area of the joined tape and was significantly dependent on the uniaxial pressure. The lap-joined tape, fabricated with a pressure of 1,000-1,600 MPa, show the highest value of current capacity(80-90%) of the tape itself. It is believed the highest value of current capacity results from improvement in core density, contacting area and grain alignment, etc. In addition, the irreversible strain( ${\varepsilon}$ irrev) for the joined tape· was measured to be 0.1%, smaller than that of enjoined tape( ${\varepsilon}$ irrev = 0.3%). The decrease in the strength and irreversible strain for joined tape is believed to be due to the irregular geometry/morphology of the transition area of the tape.

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Short-circuit Analysis of Solenoid and Pancake Type Bifilar Winding Magnets using BSCCO tape

  • Park Dong Keun;Ahn Min Cheol;Yang Seong Eun;Yoon Il Gu;Kim Young Jae;Ko Tae Kuk
    • Progress in Superconductivity and Cryogenics
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    • v.7 no.4
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    • pp.28-31
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    • 2005
  • To verify the feasibility of bifilar winding type superconducting fault current limiter (SFCL) using BSCCO tape, two types of magnets were fabricated and tested by short-circuit in this research. Even if the FCL using high Tc superconducting (HTS) tape has zero resistance in normal state, it needs to be wound as a bifilar winding for zero inductance. Solenoid type and pancake type bifilar winding magnets are designed and fabricated with the same length of BSCCO tape. The test system consists of AC power supply, transformer, fault switch, load and bifilar winding magnet. The applied AC voltages during fault duration, 0.1s, were from 0.5V to 20V. The test results without bifilar winding magnet were compared with those with each type magnets. The test results include voltage against magnet, transport current and generated resistance curve. Thermal stability, the recovery time, was studied from the results of two type magnets. The pancake type was the most effective to limit fault current but the solenoid type was thermally the most stable. From this research, short-circuit characteristics of the two types were obtained.

A Study on Joining Method of BSCCO(223) Multifilamentary Tape (BSCCO(2223) 다심 초전도 선재의 접합공정 연구)

  • 김정호;김규태;주진호;나완수
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.14 no.6
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    • pp.511-517
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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 2,50 MPa. The critical current ratio(CCR) and n-value of the jointed tape were evaluated as a function of uniaxial pressure and number of step in the contacting region. It was observed that the CCR was dependent on the number of step, but almost independent of uniaxial pressure. The highest critical current ratio and n-value were obtained to be 58% and 26%, respectively, for the jointed tape to the tape itself.

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

  • 김정호;오승진;김규태;김호진;주진호;나완수
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2001.02a
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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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