• Title/Summary/Keyword: YBaCuO powder

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STUDY ON THE PHASE CONDITION OF HTSC BULK FABRICATED BY MPMG (MPMG법으로 제작한 고온초전도bulk의 상생성 조건에 관한 연구)

  • 임성훈;최명호;한태희;강형곤;한병성
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1997.04a
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    • pp.225-228
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    • 1997
  • YBa$_2$Cu$_3$O$_{x}$ samples with different amounts of $Y_2$BaCuO$_{5}$ were prepared by MPMG (Melt Powder Melt Growth) method. The effects on the size of initial particles and Ag addition for $Y_2$BaCuO$_{5}$ distribution in YBa$_2$Cu$_3$O$_{x}$ were invesgated. The samples prepared by the melting process usually have large grains up to several ㎣ and precipitates of $Y_2$BaCuO$_{5}$. The distribution of the $Y_2$BaCuO$_{5}$ particles in the samples depends on the size of initial particles and the amounts of Ag addition.Ag addition.

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Characterization of Screen Printed $YBa_2Cu_3O_x-Ag$ Thick Films (스크린 프린팅법으로 제조된 $YBa_2Cu_3O_x-Ag$ 초전도 후막의 특성)

  • 김승구;김태윤;김대준;현상훈;정형진
    • Journal of the Korean Ceramic Society
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    • v.31 no.12
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    • pp.1483-1490
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    • 1994
  • YBa2Cu3Ox-Ag(YBCO-Ag) thick films were fabricated on the zirconia substrate by a screen printing method. The starting powder was a mixture of YBCO, prepared by a coprecipitation in oxalic acid, and Ag2O. The influence of heat treatment conditions on properties of thick films was investigated. It was observed that Jc of thick films was directly proportional to the orientation factor of thick films and the optimimum preparation condition was the heat treatment of thick films at 100$0^{\circ}C$ for 3 min in O2. The improvement of Jc by the addition of Ag was considered as a result of the suppression of microcracks in the films.

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Study on the preparation of BaPbO3 Additive for Improvement of YBCO Superconductor (YBCO 초전도체 특성 향상을 위한 첨가제 $BaPbO_3$ 제작에 관한 연구)

  • Cho, Yong-Joon;Soh, Dea-Wha;Park, Seong-Bum;Fan, Zhanguo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.11a
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    • pp.55-58
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    • 2003
  • [ $YBa_2Cu_3Ox$ ](YBCO) oxide superconductor was prepared by sol-gel method to improve its superconducting properties, and it was made to be a fine powder, which has the same property of solid state reacted powder. $BaPbO_3$ was synthesized with $BaCO_3$, BaO, PbO, and $PbO_2$ and analyzed by XRD. YBCO superconductor was prepared by use of sol-gelled YBCO powder and additive $BaPbO_3$ and its critical temperature and transition temperature were shown as 91.9 K, 3.7 K respectively in case 20 wt.% $BaPbO_3$ was added to pure sol-gelled YBCO powder.

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A study on $YBa_2Cu_3O_x$ thick films by diffusion process for a superconducting fault current limiter (확산법을 이용한 사고전류제한기용 $YBa_2Cu_3O_x$ 후막연구)

  • Cho, Dong-Eon;Yim, Seong-Woo;Choi, Myung-Ho;Han, Byoung-Sung
    • Proceedings of the KIEE Conference
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    • 1998.07d
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    • pp.1516-1518
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    • 1998
  • $YBa_2Cu_3O_x$(Yl23) Superconducting thick films on $Y_2BaCuO_5$(Y211) substrate were Prepared by surface diffusion process between $BaCuO_2$+CuO composite coating powder and a Y2ll substrate. X-ray diffraction shows that the Yl23 layer onto Y2ll substrate is the orthorhombic crystal structure. The specimen heated at $940^{\circ}C$ for 2h showed the maximum $J_c$ fo 500A/$cm^2$. Based on optimal condition, the superconducting fault current limiter(FCL) having a current limiting area 1mm wide and 66mm long was fabricated on Y211 substrate. A typical current limiting waveform was measured. When a voltage of 3V was applied, the fault current with a peak of 15A was limited to about 0.11A.

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Effect of Metal Oxide on the Superconductivity of YBCO

  • Lee, Sang-Heon
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.1241-1242
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    • 2006
  • Electromagnetic properties of $CeO_2$ doped and undoped YBaCuO superconductors were evaluated to investigate the effect of pinning center on the magnetization and magnetic shielding. The variation $\DeltaM$ with doping was maximum for 3% doping and decrease with further doping. The magnetic shielding was evaluated by measuring the induced voltage in secondary coil and the voltage initially set to 0.5V, decreased to 0.17V and 0.28V respectively for the undoped and 3% $CeO_2$ doped sample. The much less change in the induced voltage for the 3% doped sample is attributed to the increased flux shielding by shielding vortex current. The $CeO_2$ was converted to fine $BaCeO_3$ particles which were trapped in YBaCuO superconductor during the reaction sintering. The trapped fine particles, $BaCeO_3$ may be acted as a flux pinning center.

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Synthesis of YBa2Cu3O7-y Powder using a Powder Reaction Method and Fabrication of the Bulk Superconductors (분말 반응법에 의한 YBa2Cu3O7-y 합성과 벌크 초전도체의 제조)

  • Jeon, Young Ju;Park, Seung Yeon;You, Byung Youn;Park, Soon-Dong;Kim, Chan-Joong
    • Journal of Powder Materials
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    • v.20 no.2
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    • pp.142-147
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    • 2013
  • $YBa_2Cu_3O_{7-y}$ (Y123) powders for the fabrication of bulk superconductors were synthesized by the powder reaction method using $Y_2O_3$ (99.9% purity), $BaCO_3$ (99.75%) and CuO (99.9%) powders. The raw powders were weighed to the cation ratio of Y:Ba:Cu=1:2:3, mixed and calcined at $880^{\circ}C-930^{\circ}C$ in air with intermediate repeated crushing steps. It was found that the formation of Y123 powder was more sensitive to reaction temperature than reaction time. The calcined Y123 powder and a mixture of (Y123 + 0.25 mole $Y_2O_3$ + 1 wt.% $CeO_2$, $Y_{1.5}Ba_2Cu_3O_x$ (Y1.5)) were used as raw powders for the fabrication of poly-grain or single grain superconductors. The superconducting transition temperature ($T_{c,onset}$) of the sintered Y123 sample was 91 K and the transition width was as large as 11 K, whereas the $T_{c,onset}$ of the melt-grown Y1.5 sample was 90.5 K and the transition width was 3.5 K. The critical current density ($J_c$) at 77 K and 0 T of the sintered Y123 was 700 $A/cm^2$, whereas the $J_c$ of the top-seeded melt growth (TSMG) processed Y1.5 sample was $3.2{\times}10^4\;A/cm^2$. The magnetic flux density (H) at 77 K of the TSMG-processed Y123 and Y1.5 sample showed the 0.53 kG and 2.45 kG, respectively, which are 15% and 71% of the applied magnetic field of 3.5 kG. The high H value of the TSMG-processed Y1.5 sample is attributed to the formation of the larger superconducting grain with fine Y211 dispersion.

High $T_c$ Superconducting Thick Film for Applications

  • Soh, Deawha;Park, Seongbeom;Wang, Jue;Li, Fenghua;Fan, Zhanguo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.05b
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    • pp.12-15
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    • 2003
  • The YBaCuO thick film was deposited by the electrophoresis in the solution with different dimension particles. The morphology of the films deposited from different particles size was compared. The powder made by sol-gel method has the submicron particles, which deposit the most smooth film, and without microcracks after sintering. After sintering of the deposited film, the zone-melting process was carried out in low oxygen partial pressure (100 Pa) and Ag was used as substrate. And the zone-melted YBaCuO was studied by XRD.

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Formation of $YBa_2Cu_3O_x$ and the microstructure of melt infiltration processed YBCO superconductors

  • Kim, C.J.;Lee, D.M.;Park, H.S.;Jee, Y.A.;Hong, G.W.
    • Progress in Superconductivity
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    • v.1 no.2
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    • pp.89-94
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    • 2000
  • A YBCO superconductor was prepared in a short time by a melt infiltration process that utilizes meting of $Ba_3Cu5O_8$ powder and the infiltration into a porous $Y_2BaCuO_5$ compact. The processing parameters such as a reaction temperature and time, and atmosphere (air and $O_2$) were controlled to establish the fabrication condition. The formation of a $YBa_2Cu_3O_x$, phase and the developed microstructure are reported.

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Fabrication of the Bulk Superconductor by Thermal Diffusion Process (열확산 프로세스에 의한 초전도 벌크 합성)

  • Lee, Sang Heon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.34 no.6
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    • pp.461-465
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    • 2021
  • A diffusion heat treatment process for YBa2Cu3O7-y bulk superconductor in a Gd2O3 powder was attempted. As a result of measuring the critical temperature of the superconducting bulk, there was no change in the superconducting transition temperature as the Gd particles diffused into the YBa2Cu3O7-y lattice, resulting in dense microstructure. As a result of measuring the critical current, the critical current density (Jc) of the superconducting bulk having treated by the Gd thermal diffusion treatment at 0 T increased to 3×104 A/cm2 at 0 T, which was higher than that of the superconducting bulk without thermal diffusion treatment. The surface magnetic force of the superconducting bulk with Gd thermal diffusion treatment was observed at the center of the superconducting bulk with the maximum trapped magnetic force (Hmax) of 1.51 kG. This result means that the Gd thermal diffusion treatment contributes to improving the critical current density Jc of YBa2Cu3O7-y, and it is believed that Gd particles migrating into the superconducting bulk through thermal diffusion either fill the surface pores of YBa2Cu3O7-y superconductors or act as a flux pinning center.

Preparation of High Tc Superconductor Powders by Emulsion Drying Method (Emulsion 건조방법에 의한 고온초전도체 분말제조)

  • Eom, Woo-Sik;Kim, Ho-Gi
    • Korean Journal of Materials Research
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    • v.1 no.2
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    • pp.71-76
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    • 1991
  • The superconducting powders in $YBa_2Cu_3O_{7-x}$ and Bi-Pb-Sr-Ca-Cu-O system were easily prepared from water in oil type emulsion by loading each cation into the aqueous phase. In $YBa_2Cu_3O_{7-x}$ system, the superconducting orthorhombic phase was formed by calcining at $750^{\circ}C$ for 10h in $O_2$. The size of the superconducting phase powders was submicron. The density of the sintered specimen using this powders was about 95% of the theoretical density and the resistance sharply decreases at about 90K, In Bi-Pb-Sr-Ca-Cu-O system the low Tc phase($(Bi, Pb)_2Sr_2Ca_1Cu_2O_y$) was formed by calcining at $800^{\circ}C$ for 10h in a low oxygen partial pressure of 1/20 atm The shape of clacined powder is thin plate of which size is about $2\mu\textrm{m}$ and thickness is smaller than $\mu\textrm{m}$. It was observed that the high Tc phase ($(Bi, Pb)_2Sr_2Ca_2Cu_3O_y$) was formed by sintering at $850^{\circ}C$ for 30h in oxygen pressure of 1/20 atm without intermediary grinding. The above sintered sample exhibited superconductivity with a Tc(zero)=105K.

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