• Title/Summary/Keyword: ceramic oxide

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Relationship Between Voltage-time Characteristics and Microstructures of Tantalum Oxide Thin Films Prepared by Anodic Oxidation (양극 산화법으로 제조된 Tantalum Oxide 박막의 전압-시간 특성과 미세구조와의 연관성)

  • 정형진;윤상옥;이동헌
    • Journal of the Korean Ceramic Society
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    • v.28 no.6
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    • pp.443-450
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    • 1991
  • Microstructures of tantalum oxide, anodic-oxidized in oxalic acid, are shown to be related to voltage-time characteristics during formation reaction. It is observed that a crystalline phase transformed from an amorphous phase is recrystallized in the presence of the high electric field within the film, and this recrystallized film has a very porous microstructure. From the results of the XRD, the nonlinearity observed after the first spark voltage is recognized to be due to the local crystallization.

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Removal of NOx from Graphene based Photocatalyst Ceramic Filter (그래핀 기반 광촉매 담지 세라믹필터에서 질소산화물(NOx)의 제거)

  • Kim, Yong-Seok;Kim, Young-Ho
    • Applied Chemistry for Engineering
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    • v.33 no.6
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    • pp.600-605
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    • 2022
  • In this study, nitrogen oxide (NOx) removal experiments were performed using a graphene based ceramic filter coated with a V2O5-WO3-TiO2 catalyst. Graphene oxide (GO) was prepared by Hummer's method using graphite, and the reduced graphene oxide was produced by reducing with hydrazine (N2H4). Vanadium (V), Tungsten (W), and Titanium (Ti) were coated by the sol-gel method, and then a metal oxide-supported filter was prepared through a calcination process at 350 ℃. A NOx removal efficiency test was performed for the catalytic ceramic filters with UV light in a humid condition. When graphene oxide (GO) and reduced graphene oxide (rGO) were present on the filter, the NOx removal efficiency was superior to that of the conventional ceramic filter. Most likely, this is due to an improvement in the adsorption properties of NOx molecules on graphene coated surfaces. As the concentration of graphene increased, higher NOx removal efficiency was confirmed.

On the Stannic Oxide Thin Film (산화 주석 박막에 대하여)

  • 박순자
    • Journal of the Korean Ceramic Society
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    • v.13 no.2
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    • pp.8-16
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    • 1976
  • The conductive transparent film is prepared by spraying thin salt solution. In stannic chloride solution as a base solution, various dopants such as Al, Co, Cu and Ni were dissolved respectively as a chloride state and then the films were made by spraying solutions on hot glass plates. The properties of them were compared with those of the stannic salt single component film. The films doped with copper oxide and nickle oxide were improved by decreasing their sheet resistivity and temperature coefficient of resistivity. In comparison with the sheet resistivity and temperature coefficient of resistivity of stannic oxide single component film, being 2.5 K ohm/$\textrm{cm}^2$ and -1650ppm/$^{\circ}C$ respectively, its values of the film containing 15 mol % of copper oxide and formed at 40$0^{\circ}C$ were 2.5K ohm/$\textrm{cm}^2$ and -920ppm/$^{\circ}C$ respectively. The film containing 15 mol % of nickel oxide and formed at 50$0^{\circ}C$ has shown its sheet resistivity and temperature coefficient 0.7 K ohm/$\textrm{cm}^2$ and -940ppm/$^{\circ}C$ respectively.

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A Study on the Characteristics of Aluminum Oxide Thin Films Prepared by ECR-PECVD (ECR-플라즈마 화학 증착된 알루미늄 산화막 연구)

  • 이재균;전병혁;이원종
    • Journal of the Korean Ceramic Society
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    • v.31 no.6
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    • pp.601-608
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    • 1994
  • Aluminum oxide thin films were deposited on p-type(100) silicon substrates by electron cyclotron resonance plasma enhanced CVD(ECR-PECVD) using TMA[Al(CH3)3] and oxygen as reactant gases at 16$0^{\circ}C$ or lower temperatures. The aluminum oxide films deposited by ECR-PECVD have the amorphous structure with the refractive index of 1.62~1.64 and the O/Al ratio of 1.6~1.7. Oxygen flow rate necessary for the stable deposition of the aluminum oxide films increases as the deposition temperature increases. It was found from the OES analysis that the ECR plasma had les cooling effect by introducing the TMA reactant gas in comparison with the RF plasma. The properties of aluminum oxide films prepared by ECR-PECVD were compared with those prepared by RF-PECVD. The ECR-PECVD aluminum oxide films have the higher refractive indices, the lower contents of impurities (H and C) and the stronger wet etch resistance than those deposited by RF-PECVD.

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Lithium Electroactivity of Cobalt Oxide Nanoparticles Synthesized Using Thermolysis Process (열분해 공정을 통해 합성된 산화 코발트 나노입자의 리튬 전기화학반응성)

  • Jin, Yun-Ho;Shim, Hyun-Woo;Kim, Dong-Wan
    • Journal of the Korean Ceramic Society
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    • v.48 no.6
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    • pp.636-640
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    • 2011
  • Nano-sized cobalt (II) oxide nanoparticles with a high crystallinity were synthesized using thermolysis of a $Co^{2+}$-oleate precursor at 310$^{\circ}C$. The phase and morphology of as-prepared cobalt oxide nanoparticles were characterized using X-ray diffraction, high-resolution transmission electron microscopy, and Brunauer-Emmett-Teller surface area measurements. The cobalt oxide nanoparticles were found to be spherical nanoclusters with an average diameter of approximately 200 nm, consisting of tiny nanocrystals (10-20 nm). Furthermore, the Li electroactivites of the cobalt oxide nanoparticles were investigated using cyclic voltammetry and galvanostatic cycling. The cobalt oxide nanoparticles could deliver high capacities over 420 mA h $g^{-1}$ at a C/5 current rate.