• 대한금속재료학회지
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• 제46권2호
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• pp.88-96
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• 2008

Thermal evaporated 10 nm-$Ni_{50}Co_{50}$/(70 nm-poly)Si films were deposited to examine the energy saving properties of silicides formed by rapid thermal annealing at temperature ranging from 500 to $1,100^{\circ}C$ for 40 seconds. Thermal evaporated 10 nm-Ni/(70 nm-poly)Si films were also deposited as a reference using the same method for depositing the 10 nm-$Ni_{50}Co_{50}$/(70 nm-poly)Si films. A four-point probe was used to examine the sheet resistance. Transmission electron microscopy (TEM) and X-ray diffraction XRD were used to determine cross sectional microstructure and phase changes, respectively. UV-VIS-NIR and FT-IR (Fourier transform infrared spectroscopy) were used to examine the near-infrared (NIR) and middle-infrared (MIR) absorbance. TEM analysis confirmed that the uniform nickel-cobalt composite silicide layers approximately 21 to 55 nm in thickness had formed on the single and polycrystalline silicon substrates as well as on the 25 to 100 nm thick nickel silicide layers. In particular, nickel-cobalt composite silicides showed a low sheet resistance, even after rapid annealing at $1,100^{\circ}C$. Nickel-cobalt composite silicide and nickel silicide films on the single silicon substrates showed similar absorbance in the near-IR region, while those on the polycrystalline silicon substrates showed excellent absorbance until the 1,750 nm region. Silicides on polycrystalline substrates showed high absorbance in the middle IR region. Nickel-cobalt composite silicides on the poly-Si substrates annealed at $1,000^{\circ}C$ superior IR absorption on both NIR and MIR region. These results suggest that the newly proposed $Ni_{50}Co_{50}$ composite silicides may be suitable for applications of IR absorption coatings.

• 한국분말재료학회지
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• 제22권1호
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• pp.39-45
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• 2015

In this study, cobalt nanopowder is fabricated by sonochemical polyol synthesis and magnetic separation method. First, sonochemical polyol synthesis is carried out at $220^{\circ}C$ for up to 120 minutes in diethylene glycol ($C_4H_{10}O_3$). As a result, when sonochemical polyol synthesis is performed for 50 minutes, most of the cobalt precursor ($Co(OH)_2$) is reduced to spherical cobalt nanopowder of approximately 100 nm. In particular, aggregation and growth of cobalt particles are effectively suppressed as compared to common polyol synthesis. Furthermore, in order to obtain finer cobalt nanopowder, magnetic separation method using magnetic property of cobalt is introduced at an early reduction stage of sonochemical polyol synthesis when cobalt and cobalt precursor coexist. Finally, spherical cobalt nanopowder having an average particle size of 22 nm is successfully separated.

• 한국세라믹학회지
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• 제48권5호
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• pp.454-457
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• 2011

We report the preparation of nanocrystalline cobalt ferrite, $CoFe_2O_4$, particles using recycled $Co_3O_4$ and their surface coating with silica using micro emulsion method. Firstly, the $Co_3O_4$ powders were separated from waste cemented carbide with acid-base chemical treatment. The cobalt ferrite nanoparticles with the size 10 nm are prepared by thermal decomposition method using recycled $Co_3O_4$. $SiO_2$ was coated onto the $CoFe_2O_4$ particles by the micro-emulsion method. The $SiO_2$-coated $CoFe_2O_4$ particles were studied their physical properties and characterized by X-ray diffraction (XRD), high resolution-transmission electron microscopy (TEM) analysis and CIE Lab value.

• 자원리싸이클링
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• 제20권4호
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• pp.65-70
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• 2011

페리튬이온전지 양극활물질인 $LiCoO_2$로부터 코발트와 리튬을 회수하기 위한 기초 연구로 환경친화적인 유기산을 이용하여 코발트와 리튬의 침출에 관한 연구를 실시하였다. 주요 실험 변수로는 유기산 종류 및 농도, 과산화수소 농도, 반응 시간 및 온도 그리고 고액농도비 등 코발트와 리튬의 침출에 영향을 미칠 수 있는 인자들에 대하여 고찰하여 최적 조건을 얻고자 하였다. 실험 결과 사용한 유기산중에서 Latic acid가 코발트 및 리튬의 침출율이 99.9%로 가장 우수 하였다. 한편, 구연산을 이용하여 창출 실험한 결과에서 과산화수소의 농도, citric acid의 농도 및 반응온도가 증가함에 따라 코발트 및 리튬의 침출율이 증가하였다. 그러나 고액농도비가 증가함에 따라 침출율은 감소하는 경향을 보였다.

• 한국결정성장학회지
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• 제33권6호
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• pp.203-209
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• 2023

차세대 나트륨이온전지용 음극 소재로 유망한 코발트 황화물 나노복합체를 간단한 수열법을 통해 합성하였다. 본 연구에서는 배터리의 전기화학적 에너지 저장 성능 향상을 위해 코발트 황화물 나노입자와 환원된 산화그래핀과 복합화 된 코발트 황화물 나노복합체를 제조하여 비교해주었다. 제조된 나노복합체 전극은 가역적이고 안정적인 사이클 성능(전류밀도 200 mA g^-1에서 30 사이클 후 62 %)을 보였다. 개선된 전기화학적 특성은 수열합성 과정에서 코발트 황화물의 입자 크기가 작고 균일하게 분포되어 나트륨 이온의 확산 경로를 극대화함에서 기인하였다. 뿐만 아니라 전환 반응 중 음극재의 박리 및 부피 팽창을 효과적으로 억제함으로써 차세대 나트륨이온전지용 유망한 음극 소재로써의 가능성을 보여주었다.

• 한국자기학회지
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• 제4권3호
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• pp.256-262
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• 1994

코발트 단위층의 두께가 $2{\AA}$ 및 $4{\AA}$인 두 경우에 대해 막의 총두께가 약 $200{\AA}$인 Co/Pd 다층막을 제조하였으며 이 때 스퍼터링 압력이 자화반전 및 수직자기이방성에 미치는 영향에 대해 연구 하였다. 수직자기이방성 에너저지가 최대치를 보이는 압력이 존재하였으며 $2{\AA}$ 코발트층의 경우 $4{\AA}$ 경우 보다 낮은 압력에서 최대치가 나타났다. 자화시 자구벽 이동은 압력이 높을수록 어려워졌으며 높은 압력에서 는 자구벽 이동으로부터 자기모멘트 회전으로 자화반전기구가 바뀌었다. 또한 코발트층의 두께가 $2{\AA}$인 경우가 $4{\AA}$인 경우보다 수직자기이방성 에너지가 큰 것으로 나타났다.

• 상하수도학회지
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• 제38권2호
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• pp.95-107
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• 2024

This study proposes the use of a cobalt-based Prussian blue analogue (Co-PBA; potassium cobalt hexacyanoferrate), as an adsorbent for the cost-effective recovery of aqueous ammonium ions. The characterization of Co-PBA involved various techniques, including Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, nitrogen adsorption-desorption analysis, and zeta potential. The prepared Co-PBA reached an adsorption equilibrium for ammonium ions within approximately 480 min, which involved both surface adsorption and subsequent diffusion into the interior. The isotherm experiment revealed a maximum adsorption capacity of 37.29 mg/g, with the Langmuir model indicating a predominance of chemical monolayer adsorption. Furthermore, the material consistently demonstrated adsorption efficiency across a range of pH conditions. Notably, adsorption was observed even when competing cations were present. Co-PBA emerges as a readily synthesized adsorbent, underscoring its efficacy in ammonium removal and selectivity toward ammonium.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 추계학술발표대회
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• pp.28.2-28.2
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• 2009

Cobalt thin film was fabricated by a novel NH3-based plasma-enhanced atomic layer deposition(PE-ALD) using Co(CpAMD) precursor and $NH_3$ plasma. The PE-ALD Co thin films were produced well on both thermally grown oxide (100 nm) $SiO_2$ and Si(001) substrates. Chemical bonding states and compositions of PE-ALD Co films were analyzed by XPS and discussed in terms of resistivity and impurity level. Especially, we successfully developed PE-ALD Code position at very low growth temperature condition as low as $T_s=100^{\circ}C$, which enabled the fabrication of Co patterns through lift-off method after the deposition on PR patterned substrate without any thermal degradation.

• Journal of Microbiology and Biotechnology
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• 제19권5호
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• pp.530-536
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• 2009

Cobalt chloride ($CoCl_2$) treatment of cells in vitro has been shown to induce cellular changes that are similar to those seen following hypoxia. To identify genes that are differentially expressed in response to treatment with $CoCl_2$, we compared the mRNA expression profiles of PC-3 cells that were treated with $CoCl_2$ with those of untreated PC-3 cells, using specific arbitrary primers and two anchored oligo(dT) primers provided in the ACP-based GeneFishing kits. The results of this study demonstrated that the puromycin-sensitive aminopeptidase (PSA) gene was down regulated in PC-3 cells that were treated with $CoCl_2$. This downregulation of PSA expression, in turn, suppressed the proliferation, migration, and invasion of PC-3 cells, as well as the secretion and expression of matrix metalloproteinase-9 (MMP-9).

• 한국미생물·생명공학회지
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• 제14권5호
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• pp.355-358
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• 1986

M. inyoensis NRRL 3292에 의한 시소마이신 생산에 영향을 미치는 인자들에 관해 조사한 결과 cobalt chloride 및 methionine 모두가 시소마이신 생산을 현저히 촉진하였으며, 탄소원으로서는 전분 또는 덱스트린이 포도당에 비해 시소마이신 생성에 적합하였다. 특히 시소마이신 발효공정중 항생물질 생성시기에 발효액내의 용존 이산화탄소 농도가 낮을수록 시소마이신 생성 농도가 증가하였다.