• 한국재료학회지
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• 제27권3호
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• pp.155-160
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• 2017

Doped-$LaCrO_3$ perovskites, because of their good electrical conductivity and thermal stability in oxidizing and/or reducing environments, are used in high temperature solid oxide fuel cells as a gas-tight and electrically conductive interconnection layer. In this study, perovskite $(La_{0.8}Ca_{0.2})(Cr_{0.9}Co_{0.1})O_3$ (LCCC) coatings manufactured by atmospheric plasma spraying followed by heat treatment at $1200^{\circ}C$ have been investigated in terms of microstructural defects, gas tightness and electrical conductivity. The plasma-sprayed LCCC coating formed an inhomogeneous layered structure after the successive deposition of fully-melted liquid droplets and/or partially-melted droplets. Micro-sized defects including unfilled pores, intersplat pores and micro-cracks in the plasma-sprayed LCCC coating were connected together and allowed substantial amounts gas to pass through the coating. Subsequent heat treatment at $1200^{\circ}C$ formed a homogeneous granule microstructure with a small number of isolated pores, providing a substantial improvement in the gas-tightness of the LCCC coating. The electrical conductivity of the LCCC coating was consequently enhanced due to the complete elimination of inter-splat pores and micro-cracks, and reached 53 S/cm at $900^{\circ}C$.

• Korean Chemical Engineering Research
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• 제49권6호
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• pp.710-714
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• 2011

본 연구에서는 열 플라스마 용사 코팅 법을 사용하여 고체산화물 연료전지에서 사용되는 $La_{0.8}Ca_{0.2}CrO_{3}$(LCC), $La_{0.8}Sr_{0.2}CrO_{3}$(LSC), $La_{0.8}Ca_{0.2}CrO_{0.9}Co_{0.1}O_{3}$(LCCC) 세라믹 연결재를 코팅하여 코팅 층의 특성평가를 수행하였다. 열 플라즈마 코팅에 앞서 각 세라믹 연결재 입자의 특성평가를 위해 X선 회절, 미세 구조, 입자 측정 및 비표면적 분석을 수행하였다. 세라믹 연결재 입자의 특성평가 후, 열 플라스마 용사 코팅 법을 사용하여 연료극 지지체 위에 코팅하였으며, 코팅 층의 특성을 평가하기 위해 코팅 층의 표면, 파단면 분석, 가스 누출 속도 및 전기 전도도 측정을 수행하였다. 이러한 특성 평가 결과를 바탕으로 열 플라스마 용사 코팅 법을 통해 코팅된 LCCC 코팅 층이 고체산화물 연료전지의 세라믹 연결재로서 적합함을 확인하였다.

• 한국세라믹학회지
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• 제49권2호
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• pp.197-203
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• 2012

In this study, in order to improve densification of $La_{0.8}Ca_{0.2}Cr_{0.9}Co_{0.1}O_{3-\delta}$ (LCCC), which is known for one of the most proper candidate interconnector materials in the solid oxide fuel cells, $CaCrO_4$ was prepared via solid oxide synthesis route and added to the LCCC with different amount and particle sizes. As the amount of the $CaCrO_4$ increased, porosity of the sintered samples increased, and the pore size was proportional to the particle size of the $CaCrO_4$. This supports the fact that the $CaCrO_4$ phase forms liquid during sintering and permeate into the matrix leaving behind large pores. Then the liquid reacts with the matrix through the solid solution. However, when the samples were sintered with a slow ramp up rates, the porosity decreased. This is thought to be caused by the progressive solid solution of $CaCrO_4$ before the temperature reach to the melting temperature and forms a fluent amount of liquids. The sintering behavior of the LCCC with the addition of $CaCrO_4$ was analyzed through the transient liquid phase sintering on the basis of the microstructure observation and phase identification by x-ray diffraction.

• 대한토목학회논문집
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• 제37권5호
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• pp.879-890
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• 2017

기존 미국의 포장 설계법(AASHTO)과 대표적인 도로포장 유지보수 의사결정시스템인 HDM-4는 국내 실정 또는 환경에 적합하지 않아 현실적인 도로설계, 시공 및 유지관리 차원에서 국내에 적합하지 않다. 포장 수명 연장에 따른 환경비용에서도 차이가 발생할 것으로 판단되는 바, 본 연구의 주요 목표는 대한민국의 환경조건과 차종별 특성을 반영한 한국형 도로포장 설계법(KPRP) 설계 소프트웨어의 도로 공용성 해석 모델을 기반으로 활용하여 운영 및 유지보수단계에서 대표적인 세 가지 유지보수전략별 LCCC 계산을 통해 최적 대안을 선정하는 것이다. 본 연구 결과 40년 동안의 누적 탄소배출량은 대안 2의 절삭 및 덧씌우기가 누적 탄소배출량과 LCCC의 현재가치비용이 제일 적은 것으로 분석되었다. 본 연구를 통해 다양한 도로관리 유지보수 공사별 $CO_2$배출 원단위 구축이 가능하며 향후 탄소요금의 증가에 따른 도로시설별 다양한 유지관리 전략 마련에 대한 기초연구를 수행하였다는 점에 의의가 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1324-1326
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• 2000

This paper proposes a Current-Fed Push Pull type DC-DC converter using LCCC Resonant circuit and Zero Voltage Switching function to reduce turn on and off loss at the switching instants. This paper have the advantage which is able to operating safely in load short, because of DC reactor is connected with resonance reactor in order to supply a fixed current with low ripple from DC Power supply. The capacitor ($C_1$, $C_2$) connected in switch are common using as resonance capacitor and ZVS capacitor. The analysis of the proposed Current-Fed Push Pull type DC-DC converter is generally described by using normalized parameter, and we have evaluated characteristic values which is needed to design a circuit. We confirm a rightfulness theoretical analysis by comparing a theoretical values and experimental values obtained from experiment using MOSFET as switching devices.

• 한국전기전자재료학회논문지
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• 제25권5호
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• pp.392-397
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• 2012

In the $(La_{0.8}Ca_{0.2})(Cr_{0.9}Co_{0.1})O_3$ (LCCC), which has been using as interconnector materials in SOFC, Al ions were substituted for Co because ionic radius of Al is similar to that of Co. Because of the almost identical ionic radius of Al and Co, the substitution was not thought to be affect the tolerance factor of LCCC, and the densification behavior, high temperature electrical conductivity and thermal expansion coefficient were examined as a function of Al concentration. In the cases of the x= 0 and x= 0.02 in $(La_{0.8}Ca_{0.2})(Cr_{0.9}Co_{0.1-x}Al_x)O_3$ (x= 0~0.1), the samples showed the relative densities above ${\geq}95%$ when those were sintered at ${\geq}1,350^{\circ}C$. In the case of the $x{\geq}0.06$ the sintered density deteriorated greatly at lower sintering temperatures. High temperature electrical conductivity of the samples decreased as the content of Al increased. Since the valence state of Al ion is unchangeable, while Cr or Co ions contribute to the electrical conduction by changing those valence states, Al substitution resulted in the decreased electrical conductivity. Al doping of LCCC was an effective way of decreasing the thermal expansion coefficient (TEC).

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.187-190
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• 2009

$LaCrO_3$ series are the most common candidate materials for a ceramic interconnect for SOFC and the thermal expansion coefficient of these matches very well with that of YSZ electrolyte. In this study, characteristics of the coated films on the anode-support, which were formed by using $La_{0.8}Ca_{0.2}CrO_3$, $La_{0.8}Sr_{0.2}CrO_3$, $La_{0.8}Ca_{0.2}Co_{0.1}Cr_{0.9}O_3$ for ceramic interconnet for SOFC, were investigated. All powders showed single perovskite phase and the precursors had spherical shapes of $2{\mu}m{\sim}30{\mu}m$. According to SEM analysis, coated film of LCC on pretreated anode-support was more thicker, whereas the coated film on untreated anode-support was densely formed. As the results of electrical conductivity of anode-support coated with the ceramic interconnects, LCCC exhibited the most excellent electrical conductivity of 0.15S/cm at $750^{\circ}C$.