• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.406-409
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• 2001

The conductivity properties and synthesis of $LaNiO_{3}$ ceramics from $La_{1+\delta}NiO_{3}(\delta=-0.06,0,0.06)$ were investigated. A single perovskite phase was realized at $800^{\circ}C$. $La_{2}NiO_{4}$ and other unexpected oxide were observed at $1000^{\circ}C$. The Microstructure was showed clearly that it is a low density porous material. $LaNiO_3$ ceramic showed a metallic conductivity. The conductivity of La rich samples had a higher value than the La poor samples.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.406-409
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• 2001

The conductivity properties and synthesis of LaNiO$_3$ ceramics from La$\sub$1+$\delta$/NiO$_3$($\delta$=--0.06, 0, 0.06) were investigated. A single perovskite phase was realized at 800$^{\circ}C$. La$_2$NiO$_4$ and other unexpected oxide were observed at 1000$^{\circ}C$. The Microstructure was showed clearly that it is a low density porous material. LaNiO$_3$ ceramic showed a metallic conductivity. The conductivity of La rich samples had a higher value than the La poor samples.

• Bulletin of the Korean Chemical Society
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• v.17 no.8
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• pp.730-735
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• 1996

The layered perovskite oxide, KSr2Nb3O10, was synthesized. The interlayer potassium cations were readily exchanged by protons in hydrochloric acid solution to give the protonation compound, HSr2Nb3O10·0.5H2O. The intercalation compounds, [NH3(CH2)nNH3]xSr2Nb3O10, were also obtained by acid-base reactions between the protonation compound and organic bases, 1,n-alkyldiamines. The interlayer distances in the intercalation compounds were linearly increased with the increase of the number of carbon (Δc/Δn=1.05 Å) in 1,n-alkyldiamines. The intercalated alkyldiammonium ions formed a paraffin-like monolayer with average tilting angle (θ) of ca. 56°. The intercalation reactions occurred stoichiometrically. The thermal decomposition process of the intercalation compounds showed distinct three steps due to the desorption of hydrated water, the decomposition of organic moiety, and the decomposition of Sr-related compounds.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.5
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• pp.200-204
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• 2008

Mechano Chemical Process (MCP) skips the calcinations steps at an intermediate temperature that is always required in the conventional solid-state reaction because forming phase from raw powder is activated by mechanical energy. In this study, we prepared (Pb, La)$TiO_3$ nanopowder with perovskite structure by only high energy MCP. Especially, the PLT nanopowder was synthesized without any thermal treatment using oxides, not salts as raw powder. This process is also very simple due to dry milling method, unnecessary to dry of powder. The oxide powder was milled up to 12 hr at intervals of an hour using MCP and the pure PLT phase of perovskite structure was formed after milling time of 3 hr. And the average particle size was 20 nm with narrow distribution after milling time of 3 hr from raw powder of several $\mu m$ with inhomogeneous distribution.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.2
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• pp.69-74
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• 2007

[ $0.6Pb(Sc_{1/2}Ta_{1/2})O_3-0.4PbTiO_3$ ] (hereafter PSTT) ceramics were prepared by the molten salt synthesis (MSS) method using KCI as a flux. Formation of perovskite phase was investigated by a differential thermal analysis (DTA) and X-ray diffraction (XRD) analysis in the temperature range from $600^{\circ}C$ to $850^{\circ}C$. A 92% perovskite phase was synthesized at $750^{\circ}C$ for 2 hrs using the MSS method, while 82% perovskite phase was synthesized at $850^{\circ}C$ for 4ks using the calcining of mixed oxide (CMO) method. This result could be due to the improvement in reactivity of $Sc_2O_3$ by melting of KCI. The MSS specimen sintered at $1,100^{\circ}C$ for 4hrs showed a dielectric constant of 11,200, a remnant polarization of $13.5{\mu}C/cm^2$ and a coercive field of 10.198 kV/cm, which was discussed in view of the microstructure.

• New & Renewable Energy
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• v.18 no.2
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• pp.40-49
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• 2022

In this study, the phase and electrochemical properties of Co and Ti substituted layered perovskites SmBaCo_2-xTi_xO_5+d (x=0.5, 0.7, 1.0, 1.1, 1.3, and 1.5) were analyzed, and their application as electrodes in solid oxide fuel cells (SOFCs) were evaluated. After calcination at 1300℃ for 6 h, a single phase was observed for two compositions of the SmBaCo_2-xTi_xO_5+d oxide system, SmBaCoTiO_5+d (x=1.0) and SmBaCo_0.9Ti_1.1O_5+d (x=1.1). However, the phases of SmBaCoTiO_5+d (SBCTO) and SmTiO₃ coexisted for compositions with x≥1.3 (Ti content). In contrast, for compositions of x≤0.7, the SmBaCo₂O_5+d phase was observed instead of the SmTiO₃ phase. To evaluate the applicability of these materials as SOFC electrodes, the electrical conductivities were measured under various atmospheres (air, N₂, and H₂). SBCTO exhibited stable semi-conductor electrical conductivity behavior in an air and N₂ atmosphere. However, SBCTO showed insulator behavior at temperatures above 600℃ in a H₂ atmosphere. Therefore, SBCTO may only be used as cathode materials. Moreover, SBCTO had an area specific resistance (ASR) value of 0.140 Ω·cm² at 750℃.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.620-623
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• 2001

The peculiarities of using Self-propagating High-temperature Synthesis (SHS) and solid state phase synthesis for production of high temperature superconductor materials are discussed. Oxide superconductors with general formula $ReBa_2$$Cu_3$$O_{7-x}$ (Re= Y, Yb, Sm, Nd) have been made with using barium oxide initial powder instead of traditional barium carbonate. X-ray powder diffraction showed a single phase orthorhombic perovskite structure was produced in all reactions. Phenomena observed during the grinding of the reactant mixture are presented. Mechano-chemical activation - as a pretreatment of the reactant mixture - strongly influences the kinetic parameters, the reaction mechanism, and the composition and structure of the final product.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.226-240
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• 2023

This paper provides an overview of the trends and future directions in the development of anode materials for solid oxide fuel cells (SOFCs) using hydrocarbons as fuel, with the aim of enabling a decentralized energy supply. Hydrocarbons (such as natural gas and biogas) offer promising alternatives to traditional energy sources, as their use in SOFCs can help meet the growing demands for energy. We cover several types of materials, including perovskite structures, high-entropy alloys, proton-conducting ceramic materials, anode on-cell catalyst reforming layers, and anode functional layers. In addition, we review the performance and long-term stability of cells based on these anode materials and assess their potential for commercial manufacturing processes. Finally, we present a model for enhancing the applicability of fuel cell-based power generation systems to assist in the realization of the H₂ economy as the best practice for enabling distributed energy. Overall, this study highlights the potential of SOFCs to make significant progress toward a sustainable and efficient energy future.

• Korean Journal of Materials Research
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• v.8 no.12
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• pp.1152-1157
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• 1998

The PZT films were deposited on the Pt/Ti/$SiO_2$/Si substrates using multi- target DC magnetron reactive sputtering. The perovskite single phase with the composition close to the stoichiometric one, was obtained even at high substrate temperature of $540^{\circ}C$ by 2-step method, which is that PZT film was deposited for a short time at low substrate temperature ($480^{\circ}C$) to promote the nucleation of perovskite phase by reducing the volatility of Pb oxide molecules, followed by the deposition at the elevated temperature to suppress the excess incorporation of Pb component in the PZT film. This two-step method, in combination with the RTA treatment, gives rise to good electrical properties of the deposited PZT films: remanent polarifaion,$18\mu$C/$\textrm{cm}^2$; coercive field, 45kV/cm; leakage current of 10$^{-4}$ A/$\textrm{cm}^2$ at high electric field of -500kV/cm.

• Journal of the Korean Ceramic Society
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• v.45 no.4
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• pp.232-237
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• 2008

As the single chamber SOFC(SC-SOFC) showed higher prospect on reducing the operation temperature as well as offering higher design flexibility of SOFCs, lots of concerns have been given to investigate the catalytic activity of perovskite-type oxide in mixed fuel and oxidant conditions. Hence we thoroughly investigated the catalytic property of various perovskite-type oxides such as $La_{0.8}Sr_{0.2}MnO_3(LSM),\;La_{0.6}Sr_{0.4}CoO_3(LSC),\;La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3(LSCF),\;Sm_{0.5}Sr_{0.5}CoO_3(SSC),\;and\;Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}(BSCF)$ under the partial oxidation condition of methane which used to be given for SC-SOFC operation. In this study, powder form of each perovskite oxides whose surface areas were controlled to be equal, were investigated as functions of methane to oxygen ratios and reactor temperature. XRD, BET and SEM were employed to characterize the crystalline phase, surface area and microstructure of prepared powders before and after the catalytic oxidation. According to the gas phase analysis with flow-through type reactor and gas chromatography system, LSC, SSC, and LSCF showed higher catalytic activity at fairly lower temperature around $400^{\circ}C{\sim}450^{\circ}C$ whereas LSM and BSCF could be activated at much higher temperature above $600^{\circ}C$.