• Journal of the Korean Electrochemical Society
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• v.10 no.1
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• pp.7-13
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• 2007

We synthesized and investigated $La_{0.75}Sr_{0.25}FeO_3$ by Glycine Nitrate Process(GNP) method used as cathode materials for SOFC(solid oxide fuel cell). Optimized amount of glycine is 3.17 mol. ICP elemental composition analysis indicated that the stoichiometry of the synthesized powders have nearly nominal values. SEM images and XRD patterns reveal that the synthesized powder has uniform size distribution and high degree of crystallinity. The sample powders were isostatically pressed to form a pellet. The green body was sintered at $1200^{\circ}C$ and the relative density of the sintered specimens were measured by Archimedes mettled. We measured electrochemical performance of LSF by AC impedance spectroscopy. Resistance of LSF shows lower value than that of LSM throughout all temperature region. The anode-supported solid oxide fuel cell showed a performance of $342mW/cm^2(0.7V,\;488mA/cm^2)$ at $750^{\circ}C$. The electrochemical characteristics of the single cell were examined by at impedance method.

• Journal of the Korean Ceramic Society
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• v.38 no.1
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• pp.45-51
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• 2001

고체산화물 연료전지의 삼상 계면의 길이를 증가시키기 위해 Glycine-Nitrate Process(GNP)를 이용하여 환원극 재료인 L $a_{0.5}$S $r_{0.5}$Mn $O_3$(LSM)과 전해질 재료인 C $e_{0.8}$G $d_{0.2}$ $O_{1.9}$(CGO)를 합성하였다. 적당한 합성조건을 찾기 위하여 글리신의 양을 달리하여 분말을 합성한 결과 LSM의 경우 글리신이 양이온 몰수의 2배일 때 perovskite상이 얻어졌으며 비표면적은 34$m^2$/g 이었다. 합성된 LSM과 CGO 분말을 50:50 wt%로 혼합하여 제작된 환원극을 screen-printing법으로 코팅한 후 각각 1200, 1300, 1350 및 140$0^{\circ}C$에서 4시간 동안 소결한 후 80$0^{\circ}C$에서 power density와 양극과전압 등을 측정한 결과 130$0^{\circ}C$에서 소결한 단위전지에서 최대 309 mW/$ extrm{cm}^2$의 power density를 얻을 수 있었다.다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.378-382
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• 1999

저 전압용 형광체는 최근에 활발히 연구가 진행되고 있으며 가장 대표적인 형광체가 ZnO Zn 녹색 형광체이다. ZnO : Zn 형광체는 자체발광형 형광체로써 ZnO을 환원분위기 하에서 열처리를 함으로써 얻을 수 있다. 본 연구에서는 자발착화 연소반응법(Glycine Nitrate Process)을 이용하여 ZnO : Zn 분말을 합성하고 형광특성 및 분말특성을 알아보았다. 출발물질로는 Zn Nitrate와 Glycine을 이용하였고 자발연소 반웅이 발생하는데 적절한 글리신의 양을 확인하기 위해서 글리신과 양이온의 비를 변화시키며 ZnO를 합성하였다. 그리고 Zn Excess가 생겨난 앙과 그에 따른 형광특성을 관찰하기 위해 $N_2$ 분위기 에서 각기 50$0^{\circ}C$, 75$0^{\circ}C$, 95$0^{\circ}C$의 온도에서 열처리를 행하였다. 제조된 ZnO 분말의 입자형태와 결정상 태는 SEM과 XRD를 이용하여 분석하였고 TG-DTA를 측정하여 열처리온도에 따른 질량감소(Zn excess)를 관찰하였다. 또 Particle size analyzer로 분말의 크기를 알아보았고 형광체로써의 발광특성을 살펴보기 위해 PL을 이용하여 발광피크를 관찰하였다.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1517-1519
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• 1999

FED용 형광체로 사용되는 $ZnGa_2O_4$를 Glycine Nitrate Process로 합성하여 고상 반응법으로 합성한 $ZnGa_2O_4$ 분말과 비교 분석하였다. 또한 Glycine Nitrate Process로 제조시 Mn의 doping 농도를 변화시키면서 각각의 조성비에 따른 발광특성을 알아보았다. TGA 측정 결과 GNP법으로 합성된 $ZnGa_2O_4$의 경우약 $300^{\circ}C$이상에서 무게감량이 없으며, XRD 상분석 결과 연소반응 후 이미 상형성이 이루어짐을 알 수 있었다. PL측정을 결과 GP(Glycine Nitrate Process)로 제조된 $ZnGa_2O_4$ 분말의 발광효율이 고상 반응법으로 제조된 분말보다 우수하였으며, 균일하고 비표면적이 큰 단일상임이 관찰되었고, 더 작은 에너지와 시간으로 제조할 수 있는 장점이 있었다.

• Electrical & Electronic Materials
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• v.10 no.2
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• pp.141-149
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• 1997

L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ powders were prepared by both GNP(Glycine-Nitrate Process) and solid state reaction method in various of calcination temperature(800-1000.deg. C) and time in air. Also, L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ cathode contacts on YSZ(Yttria-Stabilized Zirconia) substrate were prepared by screen printing and sintering method as a function of sintering temperature(1100-1450.deg. C) in air. Sintering behaviors have been investigated by SEM(Scanning Electron Microscope) and porosity measurement. Compositional and structural characterization were carried out by X-ray diffractometer and ICP AES(Inductively Coupled Plasma-Atomic Emission Spectrometry) analysis. Electrical characterization was carried out by the electrical conductivity with linear 4 point probe method. As the calcination period increased in solid state reaction method, L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ phase increased. Although L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ single phase was obtained only for 48hrs at 1000.deg. C, in GNP method it was easy to get single and ultra-fine L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ powders with submicron particle size at 650.deg. C for 30min. The particle size and thickness of L $a_{0.7}$S $r_{0.3}$Mn $O_{3}$ cathode contact by solid state reaction method did not change during the heat treatment, while those by GNP method showed good sintering characteristics because initial powder size fabricated from GNP method is smaller than that fabricated from solid state reaction method. Based on enthalpy change from thermodynamic data and ICP-AES analysis, it was suggested to make cathode contact in composition of (L $a_{0.7}$S $r_{0.3}$)$_{0.91}$ Mn $O_{3}$ which have little second phase (L $a_{2}$Z $r_{2}$ $O_{7}$) for high efficient solid oxide fuel cells applications. As (L $a_{0.7}$S $r_{0.3}$)$_{0.91}$Mn $O_{3}$ cathode contact on YSZ substrate was sintering at 1250.deg. C the temperature that liquid phase sintering did not occur. It was possible to obtain proper cathode contacts with electrical conductivity of 150(S/cm) and porosity content of 30-40%.m) and porosity content of 30-40%.

• Transactions of the Korean hydrogen and new energy society
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• v.24 no.1
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• pp.29-35
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• 2013

A dense mixed ionic and electronic conducting ceramic membrane is one of the most promising materials because it can be used for separation of oxygen from the mixture gas. The $ABO_3$ perovskite structure shows high chemical stability at high temperatures under reduction and oxidation atmospheres. $BaCo_{1-x-y}Fe_xZr_yO_{3-{\delta}}$ (BCFZ) was well-known material as high mechanical strength, low thermal conductivity and stability in the high valence state. Glycine Nitrate Process (GNP) is rapid and effective method for powder synthesis using glycine as a fuel and show higher product crystallinity compared to solid state reaction and citrate-EDTA method. BCFZ was fabricated by modified glycine nitrate process. In order to control the burn-up reaction, $NH_4NO_3$ was used as extra nitrate. According to X-Ray Diffraction (XRD) results, BCFZ was single phase regardless of Zr dopants from y=0.1 to 0.3 on B sites. The green compacts were sintered at $1200^{\circ}C$ for 2 hours. Oxygen permeability, methane partial oxidation rate and hydrogen production ability of the membranes were characterized by using Micro Gas Chromatography (Micro GC) under various condition. The high oxygen permeation flux of BCFZ 1-451 was about $1ml{\cdot}cm^{-2}s^{-1}$. Using the humidified Argon gas, BCFZ 1-433 produced hydrogen about $1ml{\cdot}cm^{-2}s^{-1}$.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.882-884
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• 1999

금속 다층박막과 미세입상 합금박막에서 발견된 Giant Magnetoresistance(GMR)현상에 고무되어 최근에는 50년대에 밝혀졌던 산화물 자기저항 재료에 관하여 새롭게 연구하고 있다. Perovskite 구조를 가지는 $La_{1-x}Ca_{x}MnO_{3}$ 박막에서 큰 자기저항을 얻었으며 이를 Colossal Magentoresistance (CMR)이라 한다. 본 연구에서는 $La_{1-x}Ca_{x}MnO_{3}$ 분말을 고상반응법과 자발착화연소 합성법(Glycine-Nitrate Process)으로 각각 제조하였으며 비교 분석하였다. TGA을 이용하여 불순물과 미반응 물질을 확인하여 적당한 하소온도를 결정하였고 XRD를 이용하여 결정상을 분석하였다. Dilatometer를 이용해 $1400^{\circ}C$까지의 열팽창율을 측정하였다. BET로 비 표면적을 비교하였으며, 주사전자현미경(SEM)으로 각각 제조된 분말의 입자상태와 입자성장을 확인하였다. GNP법으로 합성한 경우가 고상반응법을 이용한 경우보다 입자의 크기가 submicron 단위로 미세하고 비표면적도 수배 컸으며, 고순도의 perovskite 구조를 갖는 $La_{1-x}Ca_{x}MnO_{3}$ 분말을 얻을 수 있었다.

• Journal of the Korean Ceramic Society
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• v.42 no.12 s.283
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• pp.800-807
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• 2005

Cathode material, $(Ba_{0.5}Sr_{0.5})_{0.99}Co_{0.8}Fe_{0.2}O_{3-\delta}$, for low temperature SOFC was prepared by the Glycine-Nitrate synthesis Process (GNP). Characteristics of the synthesized powders were studied with controlling the pH of a precursor solution. Highly acidic precursor solution increased a perovskite forming temperature. It is considered that Ba and Sr cannot complex by carboxylic acid group of glycine, because under highly acidic condition the caboxylic group mainly combined with H+ insead of alkaline earth cations. A lack of bond between cations and glycine resulted in selective precipitation of the elements during evaporation of the precursor solution. In case of using precursor solution with pH %2\~3$, a single perovskite phase was obtained at $1000^{\circ}C$. Polarization resistance of $(Ba_{0.5}Sr_{0.5})_{0.99}Co_{0.8}Fe_{0.2}O_{3-\delta}$ was measured by AC impedance spectroscopy from the two electrode symmetric cell. Area specific resistance of the $(Ba_{0.5}Sr_{0.5})_{0.99}Co_{0.8}Fe_{0.2}O_{3-\delta}$ air electrode at $500^{\circ}C\;and\;600^{\circ}C$ were $0.96{\Omega}{\cdot}cm^2\;and\;0.16{\Omega}{\cdot}cm^2$, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.422-425
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• 1999

Ultrafine NiO/YSZ (Yttria-Stabilized Zirconic) composite powders were prepared by using a glycine nitrate process (GNP) for anode material of solid oxide fuel cells. The specific surface areas of synthesized NiO/YSZ composite powders were examined with controlling pH of a precursor solution and the content of glycine. The binding of glycine with metal ions occurring in the precursor solution was analyzed by using FTIR. The characteristics of synthesized composite powders were examined with X-ray diffractometer, a BET method with $N_2$ absorption, scanning and transmission electron microscopies. Strongly acid precursor solution increased the specific surface area of the synthesized composite powders. This is suggested to be caused by the increased binding of metal ions and glycine under a strong acid solution of pH=0.5 that lets glycine consist of mainly the amine group of NH$_3$$^{+}$ After sintering and reducing treatment of NiO/YSZ composite powders synthesized by GNP, the Ni/YSZ pellet showed ideal microstructure very fine Ni Particles of 3-5${\mu}{\textrm}{m}$ were distributed uniformly and fine pores around Ni metal particles were formed, thus, leading to an increase of the triple phase boundary among gas, Ni and YSZ.Z.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1520-1522
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• 1999

저 전압용 형광체는 최근에 활발히 연구가 진행되고 있으며 가장 대표적인 형광체가 ZnO : Zn 녹색 형광체이다. ZnO : Zn 형광체는 자체발광형 형광체로써 ZnO을 환원분위기 하에서 열처리를 함으로써 얻을 수 있다. 본 연구에서는 자발착화 연소반응법(Glycine Nitrate Process)을 이용하여 ZnO : Zn 분말을 합성하고 형광특성 및 분말특성을 알아보았다. 출발물질로는 Zn Nitrate와 Glycine을 이용하였고 자발연소 반응이 발생하는데 적절한 글리신의 양을 확인하기 위해서 글리신과 양이온의 비를 변화시키며 ZnO를 합성하였다. 그리고 Zn Excess가 생겨난 양과 그에 따른 형광특성을 관찰하기 위해 $N_2$ 분위기에서 각기 $500^{\circ}C,\;750^{\circ}C,\;950^{\circ}C$의 온도에서 열처리를 행하였다. 제조된 ZnO 분말의 입자형태와 결정상태는 SEM과 XRD를 이용하여 분석하였고 TG-DTA를 측정하여 열처리 온도에 따른 질량감소(ZR excess)를 관찰하였다. 또 Particle size analyzer로 분말의 크기를 알아보았고 형광체로써의 발광특성을 살펴보기 위해 PL을 이용하여 발광피크를 관찰하였다.