• Journal of the Korean Ceramic Society
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• v.42 no.2 s.273
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• pp.117-122
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• 2005

Electron Beam Physical Vapor Deposition (EB-PVD) is a typical technology for thermal barrier coating with Yttria Stabilized Zirconia (YSZ) on aero gas turbine engine. In this study EB-PVD method was used to fabricate dense YSZ film on NiO-YSZ as a electrolyte of Solid Oxide Fuel Cell (SOFC). Dense YSZ films of -10 $\mu$m thickness showed nano surface structure depending on deposition temperature. Electrical conductivities of YSZ film and electric power density of the single cell were evaluated after screen- printing $LaSrCoO_3$ as a cathode.

• Korean Journal of Materials Research
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• v.11 no.6
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• pp.460-464
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• 2001

The ceramic diffusion coupling with the green body of calcium-doped lanthanum chromite(La$_{0.8}$Ca$_{0.2}$CrO$_3$CLC- G) and sintered calcium-doped lanthanum chromite(La$_{0.8}$Ca$_{0.2}$CrO$_3$ CLC) by Pechini's method on yttria stabilized zirconia(YSZ) plate has been investigated. The X-ray diffraction pattern of CLC sides at the reacted CLC-G/ CLC and CLC/YSZ interface were identified as La$_{1-x}$ Ca$_{x}$CrO$_3$ and the unreacted YSZ side was cubic-ZrO$_2$ at the treated condition, 1300~1500 C for 10 hr in air, respectively. The order of migration components between CLC/YSZ interface was Zr>La>>Cr>>>Ca and these changes were not dependent upon the treated conditions. The grain shape and size at the interface of CLC-G/CLC was appeared to have a uniform distribution with increasing temperature. The bonding reaction of YSZ/CLC was occurred without a large amount change of the compositions in SEM photos.os.otos.os.

• Korean Chemical Engineering Research
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• v.43 no.5
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• pp.627-631
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• 2005

The $(La_{0.8}Sr_{0.2})_{0.95}MnO_3$/yttria-stabilized zirconia (LSM/YSZ) composites were investigated as anode materials for high temperature steam electrolysis using X-ray diffractometry, scanning electron microscopy, galvanodynamic and galvanostatic polarization method. For this purpose, the LSMperovskites were fabricated in powders by co-precipitation method and then were mixed with 8 mol% YSZ powders in different molar ratios. The LSM/YSZ composites were deposited on 8 mol% YSZ electrolyte disks by means of a screen printing method, followed by sintering at temperatures above $1,100^{\circ}C$. From the experimental results, it is concluded that the electrochemical properties of LSM and the LSM/YSZ composites are closely related to their microstructure and operating temperatures.

• Journal of the Korean Ceramic Society
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• v.29 no.5
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• pp.377-382
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• 1992

For the development of solid oxide fuel cell the joined interface formation between perovskite oxygen electrode and YSZ solid electrolyte is emphasized in the aspect of reducing the undisirable overpotential. The diffusion couple of LaMnO3 and YSZ was prepared by hot pressing at 130$0^{\circ}C$ in the flow of oxygen gas. The high temperature solid state reaction mechanism between LaMnO3 and YSZ is discussed on the basis of the cation composition profile through EDX analysis. The cation components in perovskite compound diffuse considerably into YSZ, while cations of YSZ diffuse little into perovskite.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.103.1-103.1
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• 2011

고체 산화물 연료전지(SOFC)는 크게 음극(anode), 양극(cathode), 전해질(electrolyte)로 구성되 있으며 연결자를 통해 직렬 또는 병렬로 연결된 형태로 발전장치 등에 활용되고 있다. 이중 연료의 산화반응을 담당하고 있는 연료전지의 음극으로 지금까지 Cobalt, Platinum, Palladium 등의 전이금속 또는 귀금속들이 사용되었지만 현재는 Nickel 또는 Nickel을 함유한 물질들 특히, Ni-YSZ 복합체가 주로 사용되고 있다. Ni-YSZ 복합체는 가격과 성능 등 여러가지 면에서 SOFC의 음극으로 사용하기에 가장 적합한 물질인데 특히 전지의 지지체 역할과 동시에 전극으로서의 역할도 병행해야하는 음극 지지형 SOFC의 경우 Ni-YSZ 복합체의 효용성을 더욱 커지게 된다. 본 연구에서는 SOFC의 음극물질로 가장 널리 쓰이고 있는 Ni-YSZ 복합체를 core shell 형태로 만들어 전도 path를 효율적으로 하고 그 특성을 최적화하기 위한 미세구조 및 소결 거동, 전기적 특성을 평가하였다.

• Journal of the Korean Ceramic Society
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• v.37 no.12
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• pp.1140-1145
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• 2000

Ni의 함량이 서로 다른 Ni-YSZ 복합체를 100$0^{\circ}C$ 환원 분위기 하에서 열처리하며 시간에 따른 미세구조의 변화를 관찰하였다. Quantitative microscopy 이론을 응용한 화상분석 결과 Ni-YSZ 복합체의 미세구조는 열처리시 나타나는 Ni상의 미세구조 변화에 가장 큰 영향을 받고 있었다. 특히 Ni의 양이 많은 조성에서는 Ni 상간의 접촉이 많아 고상반응에 의한 미세구조의 변화가 심하였는데 이로 인해 복합체 미세구조의 안정화가 느리게 진행되었다. Ni-YSZ 복합체의 전기 전도도 역시 Ni상의 미세구조 변화에 큰 영향을 받았는데 복합체 전체 미세구조의 경시변화와는 달리 Ni상의 많은 조성보다는 Ni상의 percolation이 일어나는 조성 부근에서 더 큰 영향을 받았다. 이로 인해 Ni-YSZ의 전기 전도도는 Ni의 percolation threshold 부근 조성에서 안정화되는데 더 많은 시간을 요하였다.

• Journal of the Korean Ceramic Society
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• v.50 no.4
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• pp.257-262
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• 2013

A biomimetic approach was applied for the chemical deposition of calcium phosphate (CaP) coatings on 3 mole% yttrium-stabilized zirconia [3YSZ] powders. The solid-state reaction of 3YSZ powders with the addition of CaP was investigated for the development of biodegradable zirconia ceramics. The solid-state interaction between the 3YSZ matrix powders and the CaP additives differed from the behavior of commercial zirconia matrix powders. The 3YSZ powders were chemically reacted with precursors for the CaP formation. 3YSZ powders were mixed in an aqueous solution of Ca-P precursors and the CaP was precipitated on the surface of the 3YSZ matrix powders. The CaP-doped YSZ powders were calcined at $1100^{\circ}C$ and shaped powder blocks were then fired at $1600^{\circ}C$ for 2 h. The CaP phase formation was investigated using FE-SEM and XRD analysis.

• Journal of the Korean Ceramic Society
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• v.35 no.9
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• pp.899-904
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• 1998

Interface reaction between LSMC and YSZ is discussed with chemical composition of LSMC. The reac-tivity between LSMC and YSZ increased with increasing Co amount and A-site deficient perovskite is very effective on reducing reactivity. The (La0.8Sr0.2)xMn0.8Co0.2O3 (X=0.9-1) composition is not reactive with YSZ in experimental range. The electrode reaction reaction resistance increases due to reaction product.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.1
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• pp.7-12
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• 2017

3YSZ + (x) $Al_2O_3$ composites (x = 20, 40, 60, 80 wt%) were fabricated and the influences of particle sizes of $Al_2O_3$ on their microstructures and mechanical properties were investigated with XRD, SEM, vickers hardness and fracture toughness. $Al_2O_3$-3YSZ composites containing $Al_2O_3$ powder of a $0.3{\mu}m$ and an $1.0{\mu}m$, which are here in after named as $Al_2O_3$($0.3{\mu}m$)-3YSZ and $Al_2O_3$($1.0{\mu}m$)-3YSZ, respectively, were made by mixing raw materials, uni-axial pressing and sintering at $1,400^{\circ}C$, $1,500^{\circ}C$, and $1,600^{\circ}C$. $Al_2O_3$($0.3{\mu}m$)-3YSZ composites show the higher density and the better mechanical properties than $Al_2O_3$($1.0{\mu}m$)-3YSZ composites. The Vickers hardness of the $Al_2O_3$($0.3{\mu}m$)-3YSZ composites show a peak value of 1,997 Hv at the content of 60 wt% $Al_2O_3$, which is a slightly higher value in comparison with 1,938 Hv of the $Al_2O_3$($1.0{\mu}m$)-3YSZ composite. However, the fracture toughness of $Al_2O_3$-3YSZ composites monotonically increases with decreasing the content of $Al_2O_3$ without any peak values. $Al_2O_3$($0.3{\mu}m$)-3YSZ and $Al_2O_3$($1.0{\mu}m$)-3YSZ composites sintered at $1,600^{\circ}C$ have a maximum value of a $6.9MPa{\cdot}m^{1/2}$ and a $6.2MPa{\cdot}m^{1/2}$, respectively at the composition of containing 20 wt% $Al_2O_3$. It should be noticed that the mechanical properties and the sintering density of the $Al_2O_3$-3YSZ composites can be enhanced by using more fine $Al_2O_3$ powder due to their denser microstructure and smaller grain size.

• Korean Journal of Materials Research
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• v.9 no.8
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• pp.792-797
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• 1999

The 8mol.%Y$_2$$O_3$-$ZrO_2$mainly employed as an electrolyte of solid oxide fuel cells(SOFCs) shows excellent electrical properties but has a weakness in the mechanical properties. Since the electrolyte of SOFCs requires both good electrical and mechanical properties, this study was conducted to meet both requirements. The electrolyte thin films were produced on the LSM(cathode material) substrate of a cell and Si wafer. Four electrolyte film types of single layer and the multiple layer, consisting of 3-YSZ(3mol.%$Y_2$$O_3$) with excellent mechanical properties and 8-YSZ with the excellent electric conduction, were produced by electron beam coating technology. Ther crystal structure and the mechanical properties were also analysed. As the results of the study, the 3-YSZ thin film turned out to be in the tetragonal, partially monoclinic phase, while the 8-YSZ thin film showed the cubic phase. The residual stress in the multiple layer was lower than that of the single layer. The microhardness of the multiple layer was similar to that of the existing 8-YSZ single layer both before and after annealing treatment.