• 제목/요약/키워드: Sr and Fe

검색결과 468건 처리시간 0.046초

Neutron diffraction and Massbauer studies on $Sr_2Fe_{1-x}Cr_xMoO_6$

  • 유홍주;김성백;심인보;김철성;최용남;오화숙
    • 한국자기학회:학술대회 개요집
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    • 한국자기학회 2002년도 동계연구발표회 논문개요집
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    • pp.106-107
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    • 2002
  • 상온 거대자기저항 물질로 많은 연구가 이루어지고 있는 double perovskite (A$_2$BB'O$_{6}$) 계 물질은 B-site의 전이금속 윈자 종류에 따라 다양한 특성이 나타나는 것으로 보고되고 있다$^{[1]-[4]}$ . 그 중 Sr$_2$FeMoO$_{6}$ 시료가 MR 특성 및 전자기적 특성이 가장 우수한 것으로 알려져 있으나, Figure 1에 보이는 것과 같이, Sr$_2$CrMoO$_{6}$ 시료가 가장 높은 전이온도를 갖음으로 훌륭한 소자로의 응용 가능성을 보이고 있다. (중략)

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고체산화물 연료전지의 페로브스카이트와 스피넬 구조를 갖는 Sm-Sr-(Co,Fe,Ni)-O 시스템의 공기극 특성 (Cathode Properties of Sm-Sr-(Co,Fe,Ni)-O System with Perovskite and Spinel Structures for Solid Oxide Fuel Cell)

  • 백승욱;김정현;백승환;배중면
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2007년도 춘계학술대회
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    • pp.133-136
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    • 2007
  • Perovskite-structured samarium strontium cobaltite (SSC), which is mixed ionic electronic conductor (MIEC), is considered as a promising cathode material for intermediate temperature-operating solid oxide fuel cell (SOFC) due to its high electrocatalytic property. Cathode material containing cobalt (Co) is unstable at high temperature and has a relatively high thermal expansion property. In this paper, Sm-Sr-(Co,Fe,Ni)-O system with perovskite and spinel structures was investigated in terms of electrochemical property and thermal expansion property, respectively. Area specific resistance (ASR) was measured by ac impedance spectroscopy to investigate the electrochemical property of cathode, and thermal expansion coefficient (TEC) was measured by using dilatometer. Micro structure of cathode was observed by scanning electron microscopy. Perovskite-structured $Sm_{0.5}Sr_{0.5}CoO_{3-\delta}$ showed the ASR of $0.87{\Omega}/cm^{2}$, and $Sm_{0.5}Sr_{0.5}NiO_{3-\delta}$, which actually has a spinel structure, showed the lowest TEC value of $13.3{\times}10^{-6}/K$.

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Sr 페라이트 본드자석의 Nd 첨가효과 (Effects of Nd Addition to Sr Ferrite Bonded Magnet)

  • 정왕일;진성빈;강재덕;신용진
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1997년도 추계학술대회 논문집
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    • pp.120-123
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    • 1997
  • In this paper, we deal with the effect on magnetic properties when Nd is added to Sr ferrite bonded magnet. First, we choose SrO$_{n}$.Fe$_2$O$_3$(n=5.9), which is nonstoichiomatric composition, as specimen ferrite. Then, we add 5wt% polyvinyl alcohol and calcinate at 12$25^{\circ}C$ under $N_2$ environment for carbon coating on chemical compound specimen. After that we obtain 1.2${\mu}{\textrm}{m}$ single domain powder through grinding process for 18 hours. The single domain Sr ferrite Powder is well mixed with silage coupling and calcium stearate of 1wt% Then, it is kneaded by using polyamide12 as a binder and is pelleted. After adding Nd-Fe-B powder to the pelleted specimen, we injection-mould it under magnetic field by using anisotropic mould. Especially, when we add l3wt% Nd-Fe-B powder to the polyamide12, we obtain excellent magnetic propertiecs which are $_{B}$H$_{C}$=2.65KOe, Br=3.16KG and (BH)$_{max}$=2.61MGOeOeOeOeOe

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SOFC의 세라믹 음극물질로서 Y0.08Sr0.92Fe0.3Ti0.7O3의 합성 및 물성 평가 (Synthesis and Properties of Y0.08Sr0.92Fe0.3Ti0.7O3 as Ceramic Anode for SOFC)

  • Lee, Tae-Hee;Jeon, Sang-Yun;Im, Ha-Ni;Song, Sung-Ju
    • KEPCO Journal on Electric Power and Energy
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    • 제7권1호
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    • pp.161-165
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    • 2021
  • In general, SOFCs mainly use Ni-YSZ cermet, a mixture of Ni and YSZ, as an anode material, which is stable in a high-temperature reducing atmosphere. However, when SOFCs have operated at a high temperature for a long time, the structural change of Ni occurs and it results in the problem of reducing durability and efficiency. Accordingly, a development of a new anode material that can replace existing nickel and exhibits similar performance is in progress. In this study, SrTiO3, which is a perovskite-based mixed conductor and one of the candidate materials, was used. In order to increase the electrical conduction properties, Y0.08Sr0.92Fe0.3Ti0.7O3, doped with 0.08 mol of Y3+ in Sr-site and 0.03 mol of transition metal Fe3+ in Ti-site, was synthesized and its chemical diffusion coefficient and reaction constant were measured. Its electrical conductivity changes were also observed while changing the oxygen partial pressure at a constant temperature. The performance as a candidate electrode material was verified by predicting the defect area through the electrical conductivity pattern according to the oxygen partial pressure.