• 제목/요약/키워드: $Ce_{0.8}Sm_{0.2}O_2$

검색결과 17건 처리시간 0.031초

국부용융성장법으로 제조한 (Sm/Y)-Ba-Cu-0계 고온복합초전도체의 CeO2첨가에 따른 초전도특성 (Superconducting Properties of (Sm/Y)-Ba-Cu-0 High Tc Composite Superconductors with CeO2 Additive by Zone-Melt Textured Growth)

  • 김소정
    • 한국전기전자재료학회논문지
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    • 제15권3호
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    • pp.269-274
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    • 2002
  • (Sm/Y)-Ba-Cu-O system high Tc composite superconductors with/without $CeO_2$ additive were directionally grown by zone-melting process, haying large temperature gradient, In air atmosphere. Cylindrical green rods of $({Sm/y})_{1.8}Ba_{2.4}Cu_{3.4}O_x$ [(Sm/Y)1.8] composite oxides by cold isostatic pressing(CIP) method using rubber mold were fabricated. The microstructure and superconducting properties were investigated by XRD, SEM, TEM and SQUID magnetometer. The size of nonsuperconducting $({Sm/y})_2BaCuO_5$ inclusions of the melt-textured (Sm/Y)1.8 sample with CeO$_2$ additive were remarkably reduced and uniformly distributed within the superconducting (Sm/Y)1.8 matrix. Both samples, with/without $CeO_2$ additive, showed an onset Tc $\geq$ 90 K and sharp superconducting transition. The critical current density Jc value of the $CeO_2$ addictive were $1{\times}10^5A/\textrm{cm}^2$ in 77 K, 0 Tesla.

Ce0.8Sm0.2O2 Sol-gel Modification on La0.8Sr0.2Mn0.8Cu0.2O3 Cathode for Intermediate Temperature Solid Oxide Fuel Cell

  • Lee, Seung Jin;Kang, Choon-Hyoung;Chung, Chang-Bock;Yun, Jeong Woo
    • 마이크로전자및패키징학회지
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    • 제22권4호
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    • pp.77-82
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    • 2015
  • To increase the performance of solid oxide fuel cell operating at intermediate temperature ($600^{\circ}C{\sim}800^{\circ}C$), $Sm_{0.2}Ce_{0.8}O_2$ (SDC) thin layer was applied to the $La_{0.8}Sr_{0.2}Mn_{0.8}Cu_{0.2}O_3$ (LSMCu) cathode by sol-gel coating method. The SDC was employed as a diffusion barrier layer on the yttria-stabilized zirconia(YSZ) to prevent the interlayer by-product formation of $SrZrO_3$ or $La_2Zr_2O_7$. The by-products were hardly formed at the electrolyte-cathode interlayer resulting to reduce the cathode polarization resistance. Moreover, SDC thin film was coated on the cathode pore wall surface to extend the triple phase boundary (TPB) area.

고체산화물 연료전지의 Samarium Oxide 혼합 공기극에 대한 열특성 분석 (Thermal Characteristics of Samarium-based Composite Cathode ($Sm_{0.5}Sr_{0.5}CoO_{3-\delta}/ Sm_{0.2}Ce_{0.8}O_{1.9}$) for Intermediate Temperature-operating Solid Oxide Fuel Cell)

  • 백승욱;배중면
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회B
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    • pp.2021-2025
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    • 2007
  • Performance of single cell at solid oxide fuel cell (SOFC) system is largely affected by electrocatalytic and thermal properties of cathode. Samarium-based perovskite oxide material is recently recognized as promising cathode material for intermediate temperature-operating SOFC due to its high electrocatalytic property. Perovskite structured $Sm_{0.5}Sr_{0.5}CoO_{3-\delta}$ and its composite material, $Sm_{0.5}Sr_{0.5}CoO_{3-\delta}/Sm_{0.2}Ce_{0.8}O_{1.9}$ were investigated in terms of area specific resistance (ASR), thermal expansion coefficient (TEC), thermal cycling and long term performance. $Sm_{0.2}Ce_{0.8}O_{1.9}$ was used as electrolyte material. Electrochemical ac impedance spectroscopy (EIS) and dilatometer were used to measure the cathodic properties. Composite cathode ($Sm_{0.5}Sr_{0.5}CoO_{3-\delta}$: $Sm_{0.2}Ce_{0.8}O_{1.9}$ = 6:4) showed a good ASR of 0.13${\Omega}$ $cm^2$ at 650$^{\circ}C$ and its TEC value was 12.3${\times}$10-6/K at 600$^{\circ}C$ which is similar to the value of ceria-based electrolyte of 11.9${\times}$10-6/K. Performance of composite cathode was maintained with no degradation even after 13 times thermal cycle test.

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[(CeO2)1-x(ZrO2)x]0.8(SmO1.5)0.2 고용체의 전기전도도 (Electrical Conductivities of [(CeO2)1-x(ZrO2)x]0.8(SmO1.5)0.2 Solid Solution)

  • 이충연;김영식;김남철
    • 한국전기전자재료학회논문지
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    • 제16권9호
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    • pp.775-782
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    • 2003
  • In the study, the total conductivies in [(Ce $O_2$)$_{1-x}$ (Zr $O_2$)$_{x}$]$_{0.8}$(Sm $O_{1.5}$)$_{0.2}$ (x- 0, 0.05, 0.1, 0.2) solid solution were measured as a function of temperature and oxygen partial pressure between 80$0^{\circ}C$ and 1,00$0^{\circ}C$ using 4-probe d.c method. Under pure oxygen atmospere, the oxygen ionic conductivity of [(Ce $O_2$)$_{1-x}$ (Zr $O_2$)$_{x}$]$_{0.8}$(Sm $O_{1.5}$)$_{0.2}$ decreased with the concentration of Zr $O_2$At high oxygen partial pressure, the electrical conductivity is almost independent of oxygen partial pressure and decreased with the increase in Zr content. However, the electrical conductivity increase with decreasing oxygen partial pressure and is almost independent of Zr content at low oxygen partial pressure. Empirically, Total conductivity( $\sigma$ ) was expressed by the p$o_{2}$ -independent conductivity as $\sigma$$_{i}$, and the $p_{-1/4}$ $o_{2}$sup -dependent part as $\sigma$$_{e}$. Total, ionic and electronic conductivities fitted by data enabled to determine the transference number. The ionic transference number( $t_{i}$ ) decreased while the electronic transference( $t_{e}$ ) increase with the increase in Zr content and p$o_{2}$.

존멜팅법으로 제조한 (YNdSm)-Ba-Cu-O계 고온복합초전도체의 미세구조 및 전기적 특성 (Microstructure and Electrical Properties of (YNdSm)-Ba-Cu-O High Tc Composite Superconductors by Zone Melting Process)

  • 김소정;이상헌
    • 한국전기전자재료학회논문지
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    • 제29권2호
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    • pp.110-113
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    • 2016
  • (YNdSm)-Ba-Cu-O system high Tc composite superconductors were directionally grown by zone melting process, having large temperature gradient, in air atmosphere. Cylindrical green rods of $(YNdSm)_{1.8}Ba_{2.4}Cu_{3.4}O_x$ [(YNS)1.8]composite oxides by CIP (cold isostatic pressing) method using rubber mold were fabricated. The microstructure and superconducting properties were investigated by XRD, TEM and SQUID magnetometer. The size of nonsuperconducting $(YNdSm)_2BaCuO_5$ inclusions of the melt-textured (YNS)1.8 sample with $CeO_2$ additive were remarkably reduced and uniformly distributed within the superconducting (YNS)1.8 matrix. (YNS)1.8 samples, with / without $CeO_2$ additive, showed an onset $T_c{\geq}90K$ and sharp superconducting transition. The critical current density $J_c$ value of the (YNdSm)1.8 superconductor with $CeO_2$ additive were 840 A, $1.2{\times}104A/cm^2$ in 77 K, 0 Tesla by direct current transport method.

The Study of Different Buffer Structure on Ni-W Tape for SmBCO Coated Conductor

  • Kim, T.H.;Kim, H.S.;Oh, S.S.;Ko, R.K.;Ha, D.W.;Song, K.J.;Lee, N.J.;Yang, J.S.;Jung, Y.H.;Youm, D.J.;Park, K.C.
    • 한국초전도ㆍ저온공학회논문지
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    • 제8권4호
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    • pp.8-11
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    • 2006
  • High temperature superconducting coated conductor has various buffer structures on Ni-W alloy. We comparatively studied the growth conditions of a multi buffer layer $(CeO_2/YSZ/CeO_2)$ and a single buffer layer$(CeO_2)$ on textured Ni-W alloy tapes. XRD data showed that the qualities of in-plane and out-of-plane textures of the two type buffer structures were good. Also, we investigated the properties of SmBCO superconducting layer that was deposited on the two type buffer structure. The SmBCO superconducting properties on the single and multi buffer structure showed different critical current values and surface morphologies. FWHM of In-plane and out-of-plane textures were $7.4^{\circ},\;5.0^{\circ}$ in the top CeO2 layer of the multi-buffer layers of $CeO_2/YSZ/CeO_2$, and $7.3^{\circ},\;5.1^{\circ}$ in the $CeO_2$ single buffer layer. $1{\mu}m-thick$ SmBCO superconducting layers were deposited on two type buffer layer. $I_c$ of SmBCO deposited on single and multi buffer were 90 A/cm, 150 A/cm and corresponding $J_c$ were $0.9MA/cm^2,\;1.5MA/cm^2$ at 77K in self-field, respectively.

$CeO_2$ 단일 완충층을 이용한 SmBCO 초전도테이프 제조 (Fabrication of SmBCO coated conductors using $CeO_2$ single buffer layers)

  • 김태형;김호섭;하홍수;오상수;양주생;하동우;송규정;이남진;정예현;박경채
    • 한국초전도ㆍ저온공학회논문지
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    • 제8권3호
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    • pp.32-36
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    • 2006
  • Simplification of the buffer architecture in the fabrication of coated conductors is required because the deposition of multi-layers leads to a longer production time and a higher cost of coated conductors. In this study, a single layered buffer deposition of $CeO_2$ for low cost coated conductors has been tried using thermal evaporation technique. l00nm-thick $CeO_2$ layers deposited by thermal evaporation were found to act as a diffusion layer. $0.4{\mu}m$-thick SmBCO superconducting layers were deposited by thermal co-evaporation on the $CeO_2$ buffered Ni-W substrate. Critical current of $55.4 A/cm^2$ was obtained for the SmBCO coated conductors.

An SOFC Cathode Composed of LaNi0.6Fe0.4O3 and Ce(Ln)O2 (Ln=Sm, Gd, Pr)

  • Chiba, Reiichi;Komatsu, Takeshi;Orui, Himeko;Taguchi, Hiroaki;Nazawa, Kazuhiko;Arai, Hajime
    • 한국세라믹학회지
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    • 제45권12호
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    • pp.766-771
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    • 2008
  • We fabricated single cells with a cathode consisting of a $LaNi_{0.6}Fe_{0.4}O_3-Ce_{0.8}Sm_{0.2}O_{1.9}$ composite (LNF-S20DC composite) active layer and an LNF current collecting layer on a ${0.89ZrO_2}-{0.10Sc_2}{O_3}-0.01{Al_2}{O_3}$ electrolyte sheet. The cathode layers were prepared by the screen-printing method. The cathode properties of these cells were measured by the AC impedance method at $800^{\circ}C$. The cathodes with the ceria-LNF composite active layer exhibited high power performance prior to current loading. We investigated the influence of the mixture ratio of LNF and S20DC on the cathodes properties. The Sm in the ceria particles of the composite cathode was substituted with other rare-earth elements. Cathodes with Pr and Gd co-doped ceria in the active layer provided the better performance than those with Sm- or Gd-doped ceria.

H2S tolerance effects of Ce0.8Sm0.2O2-δ modification on Sr0.92Y0.08Ti1-xNixO3-δ anode in solid oxide fuel cells

  • Kim, Kab In;Kim, Hee Su;Kim, Hyung Soon;Yun, Jeong Woo
    • Journal of Industrial and Engineering Chemistry
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    • 제68권
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    • pp.187-195
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    • 2018
  • $Sr_{0.92}Y_{0.08}Ti_{1-x}Ni_xO_{3-{\delta}}$ (SYTN) was investigated in the presence of $H_2S$ containing fuels to assess the feasibility of employing oxide materials as alternative anodes. Aliovalent substitution of $Ni^{2+}$ into $Ti^{4+}$ increased the ionic conductivity of perovskite, leading to improved electrochemical performance of the SYTN anode. The maximum power densities were 32.4 and $45.3mW/cm^2$ in $H_2$ at $900^{\circ}C$ for the SYT anode and the SYTN anode, respectively. However, the maximum power densities in 300 ppm of $H_2S$ decreased by 7% and by 46% in the SYT and the SYTN anodes, respectively. To enhance the sulfur tolerance and to improve the electrochemical properties, the surface of SYTN anode was modified with samarium doped ceria (SDC) using the sol-gel coating method. For the SDC-modified SYTN anode, the cell performance was mostly recovered in the pure $H_2$ condition after 500-ppm $H_2S$ exposure in contrast to the irreversible cell performance degradation exhibited in the unmodified SYTN anode.

ANISOTROPY CONSTANTS OF $(Sm_{0.5}RE_{0.5})Fe_{11}Ti$ COMPOUNDS (RE=RARE EARTH)

  • Kim, H.T.;Kim, Y.B.;Park, W.S.;Kim, C.S.;Kim, T.K.;Jin, Han-Min
    • 한국자기학회지
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    • 제5권5호
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    • pp.683-686
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    • 1995
  • Using by the x-ray diffractometry(XRD), the thermomagnetic analysis(TMA), a scanning electron microscopy (SEM-EDX), we knew that the $(Sm_{0.5}RE_{0.5})Fe_{11}Ti$ (RE=Ce,Pr,Nd,Sm,Gd,Tb) compounds were formed to tetragonal $ThMn_{12}$-type structure having a uniaxial magnetocrystalline anisotropy with easy magnetization c-axis. The intrinsic magnetic properties of those were determined by fitting the two magnetization curves of experimental and calculation magnetization. The anisotropy constant $K_{1}$ of this compounds was in the range of $1.75\;-\;9.2\;MJ/m^{3}$ and approximately one order higher than $K_{2}$. $SmFe_{11}Ti$ had the highest anisotropy of $K_{1}\;=\;9.2\;MJ/m^{3}$, $K_{2}\;=\;0.4\;MJ/m^{3}$ and ${\mu}_{o}H_{A}=\;19.8\;T$ among the compounds, substitution of any other rare earth elements for Sm decreased magnetocrystalline anisotropy.

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