• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.470-473
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• 2002

In order to get proper original suspension for the electrophoresis process of making YBaCuO films, YBaCuO superconductor powder was prepared with the Sol-gel method. The composition of the powder was analyzed by X-ray diffraction, which was identified as YBa$_2$Cu$_3$O$\sub$7-x/(Yl23) phase. The form of YBaCuO single particle was showed to be spherical by scanning electronic microscope and its size was among 0.2-1 $\mu\textrm{m}$. The critical transition temperature (T$\sub$c/) and the critical current density (J$\sub$c/) were measured with the four-probe, method. The T$\sub$c/ was about 91 K, and the J$\sub$c/ was 5-30 A/$\textrm{cm}^2$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.557-560
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• 2003

The submicron $YBa_2Cu_3O_x$ powder was prepared by the sol-gel method. The particle size is distributed from 0.2 to $1.0\;{\mu}m$, which benefits to eliminate the micro-cracks formed in the $YBa_2Cu_3O_x$ films deposited by electrophoresis. The powder was single phase of $YBa_2Cu_3O_x$ examined by X-ray diffraction. In the sol-gel process the citrate gel was formed from citric acid and nitrate solution of $Y_2O_3$, $Ba(NO_3)O_2$ and CuO. When pH values were adjusted to $6.4{\sim}6.7,\;Ba(NO_3)O_2$ could be dissolved in the citrate solution completely. Appropriate evaporative temperature of the sol-gel formation is discussed. After the heat treatment the transition temperature($T_c$) and critical current density($J_c$) of the $YBa_2Cu_3O_x$ samples made of the submicron powder were measured.

• 한국초전도ㆍ저온공학회논문지
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• 제1권1호
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• pp.15-21
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• 1999

Textured bulk $YBa_2Cu_3O_x$ superconductors samples were grown directionally using different precursors of $YBa_2Cu_3O_x$ power. and a mixture of $YBa_2Cu_3O_5, BaCuO_2 and CuO$ powder. The microstructures and superconducting properties of the samples were compared. The mixture powder produced better microstructures i.e. dense and crack-free so that a higher critical current density was achieved at the same hot-zone temperature of 115$0^{\circ}C$ than the reacted powder does. When the reacted powder used as a precursor, as the hot-zone temperature increased upto 1215$^{\circ}C$, the texture of the sample improved and the critical current density increased. The amount of melt in the sample is of secondary importance for the growth of superconducting $YBa_2Cu_3O_x$ grains. The microstructures and superconductivity of good quality superconductors grown directionally were more strongly influenced by the kind of precursor rather than the amount og melt in a sample.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 춘계종합학술대회
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• pp.366-369
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• 2003

High T$_{c}$ superconducting lines will be applied as key materials in the areas of power transmission line; magnetic levitation of vehicle; magnetic separation; magnetic energy storage and marine propulsion. A combination method of electrophoresis deposition and zone-melting for preparation of YBaCuO tape is proposed. The submicron particle powder of YBaCuO made by sol-gel method is used in the electrophoresis process. A 40~50${\mu}{\textrm}{m}$ thickness of YBaCuO film on Ag plate could be deposited in about three minutes. After deposition the film is rolled and heat treated in order to increase the density and the adhesion of the film to the Ag plate. Silver(Ag) and lead oxide(PbO) were added in the YBaCuO powder in order to reduce its melting point. The YBaCuO coating with controlled Ag and PbO contents was preliminarily zone-melted at about 945$^{\circ}C$.>.

• Journal of information and communication convergence engineering
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• 제1권2호
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• pp.63-66
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• 2003

High $T_c$ superconducting lines will be applied as key materials in the areas of power transmission line; magnetic levitation of vehicle; magnetic separation; magnetic energy storage and marine propulsion. A combination method of electrophoresis deposition and zone-melting for preparation of YBaCuO tape is proposed. The submicron particle powder of YBaCuO made by sol-gel method is used in the electrophoresis process. A 40∼50 ${\mu}\textrm{m}$ thickness of YBaCuO film on Ag plate could be deposited in about three minutes. After deposition the film is rolled and heat treated in order to increase the density and the adhesion of the film to the Ag plate. Silver(Ag) and lead oxide(PbO) were added in the YBaCuO powder in order to reduce its melting point. The YBaCuO coating with controlled Ag and PbO contents was preliminarily zone-melted at about $945^{\circ}C$.

• 한국정보통신학회논문지
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• 제15권8호
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• pp.1771-1776
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• 2011

미세 입자 크기를 갖는 $YBa_2Cu_3Ox$(YBCO) 초전도 분말을 이용하여 $BaPbO_3$ 첨가에 따른 $YBa_2Cu_3Ox$ 초전도 벌크의 임계전류를 향상시키는 요소인 시편의 밀도와 결정들의 정렬 상태를 향상시키고, 기공도를 감소시키기 위한 연구를 수행하였다. 졸겔법으로 미세 크기를 갖는 $YBa_2Cu_3Ox$ 초전도 분말을 합성하여 입자의 크기가 0.2~1 ${\mu}m$의 미세한 분포를 갖는 초전도 분말을 사용하고, $YBa_2Cu_3Ox$ 초전도 시편의 입자 성장을 촉진시키고, 기공과 입계간의 약연접을 감소시키기 위하여 금속 물질 및 구조 화합물인 $BaPbO_3$를 10~30 wt%를 첨가하여 시편을 제작하고 특성을 관찰하였다. 나노 크기를 갖는 YBCO 분말과 $BaPbO_3$ 20 wt%를 첨가하여 제작한 $YBa_2Cu_3Ox$ 초전도 시편은 일반적인 벌크 제작법으로 제작된 시편과 비교하여 임계전류가 20% 향상된 4.74A를 얻었다.

• 한국자기학회지
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• 제4권1호
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• pp.48-51
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• 1994

$^{63}Cu$ 핵사중극공명을 이용하여 자기적으로 정렬된 $YBa_{2}Cu_{3}O_{7}$ 고온초전도체 시료의 비등방성을 조사하였다. 정렬된 시료에서는 RF 자기장이 c-축에 수직으로 가해질 때만 공명신호가 검출되었다. 자기적으로 정렬된 시료와 정렬되지 않은 시료로부터 측정된 공명차이로부터 $YBa_{2}Cu_{3}O_{7}$의 자기적 비등방성을 관측할 수 있었다.

• 동굴
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• 제76호
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• pp.49-55
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• 2006

The submicron $YBa_2Cu_3O_x$ powder was prepared by the sol-gel method. The particle size is distributed from 0.2 to 1.0 ${\mu}m$, which benefits to eliminate the micro-cracks formed in the $YBa_2Cu_3O_x$ films deposited by electrophoresis. The powder was single phase of $YBa_2Cu_3O_x$ examined by X-ray diffraction. In the sol-gel process the citrate gel was formed from citric acid and nitrate solution of $Y_2O_3$, $Ba(NO_3)_2$ and CuO. When pH values were adjusted to 6.4-6.7, $Ba(NO_3)_2$ could be dissolved in the citrate solution completely. Appropriate evaporative temperature of the sol-gel formation is discussed. Acetone is used as electrophoreticsolution, in which some water and iodine (0.2 g/1) and polyethylene glycol (2 vol. %) are added. The concentrations of $YBa_2Cu_3O_x$ powders is 20g/l. The thickness of deposited film could be more than 50 ${\mu}m$ in 3 minutes of depositing time. The most EPD films could be 90K zero resistance and the Jc values were over 1000A/cm2 (0 H, 77 K).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.263-266
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• 2003

The fine $YBa_2Cu_3O_x$ powder ($0.2{\sim}1.0\;{\mu}m$) is produced by sol-gel method, and electrophoresis deposition is used for the preparation of $YBa_2Cu_3O_x$ thick films which are deposited on Ag wire. The oriented $YBa_2Cu_3O_x$ was tried to be prepared by the zone-melting method under low oxygen partial pressure. The orientation and the phase composition were examined by the X-ray diffraction and the superconductivities were measured by 4 line method. The critical current densities are still quite low, which may be due to unsuitable technical parameters for zone-melting of $YBa_2Cu_3O_x$ thick films. Therefore the heat treatment condition and controlling of low oxygen partial pressure should be improved in the future experiment.

• 한국분말재료학회지
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• 제7권4호
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• pp.205-211
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• 2000

Distribution of $Y_2BaCuO_5$ (211) Particles within $YBa_2Cu_3O_{7-x}/$ (123) grains of melt infiltration processed YBCO oxides was investigated. Processing parameters were a temperature, atmosphere (air and $O_2$) and initial 211 size. The 211 particles were distributed randomly within the 123 grains when the initial 211 size was large, while they made x-like pattern and/or butterfly-like patterns when the 211 size was small. The 211 patterns were more clearly observed in the samples prepared at higher temperatures and under $O_2$ atmosphere. The 211 distribution was explained in terms of the interfacial energy relationship among the solid, particle and melt.