• Title/Summary/Keyword: $CuOH^+$

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THE EFFECT OF Cu SUBSTITUTION ON THE PROPERTIES OF NiZn FERRITE

  • Nam, J.H.;Jung, H.H.;Shin, J.Y.;Oh, J.H.
    • Journal of the Korean Magnetics Society
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    • v.5 no.5
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    • pp.548-551
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    • 1995
  • The effect of Cu substitution on the properties of NiZn ferrites sintered at low temperature with composition is investigated. The densification of NiCuZn ferrite in dependent upon Cu content in the composition of (N/sub 0.5-x/Cu/sub x/ Zn/sub 0.5/O)(Fe/sub 2/O/sub 3/)/sub 0.98/. Electrical resistivity is maximum at x=0.2. Dispersion characteristics of complex permeability of (Ni/sub 0.5-x/ Cu/sub x/Zn/sub 0.5/O)(Fe/sub 2/O/sub 3)/sub 0.98/ is observed above x=0.3 and relaxation frequency increases with higher temperature. The magnetic loss of NiCuZn ferrite is occurred above the Cu content x=0.3 at a low frequency.

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Effects of Citric Acid as a Complexing Agent on Material Removal in Cu CMP (Cu CMP에서 Citric Acid가 재료 제거에 미치는 영향)

  • Jung Won-Duck;Park Boum-Young;Lee Hyun-Seop;Jeong Hea-Do
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.10
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    • pp.889-893
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    • 2006
  • Chemical mechanical polishing (CMP) achieves surface planrity through combined mechanical and chemical means. The role of slurry is very important in metal CMP. Slurry used in metal CMP normally consists of oxidizers, complexing agents, corrosion inhibitors and abrasives. This paper investigates the effects of citric acid as a complexing agent for Cu CMP with $H_2O_2$. In order to study chemical effects of citric acid, X-ray photoelectron spectroscopy (XPS) was peformed on Cu sample after etching test. XPS results reveal that CuO, $Cu(OH)_2$ layer decrease but $CU/CU_2O$ layer increase on Cu sample surface. To investigate nanomechanical properties of Cu sample surface, nanoindentation was performed on Cu sample. Results of nanoindentation indicate wear resistance of Cu surface decrease. According to decrease of wear resistance on Cu surface removal rate increases from $285\;{\AA}/min\;to\;8645\;{\AA}/min$ in Cu CMP.

Characteristics of Removal and Precipitation of Heavy Metals with pH change of Artificial Acid Mine Drainage (인공 산성광산배수의 pH변화에 의한 중금속 제거 및 침전 특성 연구)

  • Lee, Min Hyeon;Kim, Young Hun;Kim, Jeong Jin
    • Economic and Environmental Geology
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    • v.52 no.6
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    • pp.529-539
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    • 2019
  • In this study, heavy metal removal and precipitation characteristics with pH change were studied for artificial acid mine drainage. Artificial acid mine drainage was prepared using sulfates of iron, aluminum, copper, zinc, manganese which contained in acid mine drainage from abandoned mines. The single and mixed five heavy metal samples of Fe, Al, Cu, Zn, and Mn were prepared at initial concentrations of 30 and 70 mg/L. Fe and Al were mostly removed at pH 4.0 and 5.0, respectively, and other heavy metals gradually decreased with increasing pH. Concentration changes with increasing pH show generally similar trend for single and mixed heavy metal samples. The effect of removing heavy metals from aqueous solutions is not related to the initial concentration and depends on the pH change. XRD were used for mineral identification of precipitates and crystallinity of the mineral tended to increase with increasing pH. The precipitates that produced by decreasing the concentration of heavy metals in the aqueous solution composed of Fe-goethite(FeOOH), Al-basaluminite(Al4(SO4)(OH)10·4H2O), Cu-connellite(Cu19(OH)32(SO4)Cl4·3H2O) and tenorite(CuO), Zn-zincite(ZnO), and Mn-hausmannite(Mn3O4).

The Characteristic Dissolution of Valuable Metals from Mine-Waste Rock by Heap Bioleaching, and the Recovery of Metallic Copper Powder with Fe Removal and Electrowinning (더미 미생물용출에 의한 폐-광석으로부터 유용금속 용해 특성과 Fe 제거와 전기분해를 이용한 금속구리분말 회수)

  • Kim, Bong-JuK;Cho, Kang-Hee;Choi, Nag-Choul;Park, Cheon-Young
    • Journal of the Mineralogical Society of Korea
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    • v.27 no.4
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    • pp.207-222
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    • 2014
  • In order to recover the metallic copper powder from the mine-waste rock, heap bioleaching, Fe removal and electrowinning experiments were carried out. The results of heap leaching with the mine-waste rock sample containing 0.034% Cu showed that, the leaching rate of Cu were 61% and 62% in the bacteria leaching and sulfuric acid leaching solution, respectively. Sodium hydroxide (NaOH), hydrogen peroxide ($H_2O_2$) and calcium hydroxide ($Ca(OH)_2$) were applied to effectively remov Fe from the heap leaching solution, and then $H_2O_2$ was selected for the most effective removing Fe agent. In order to prepare the electrolytic solution, $H_2O_2$ were again treated in the heap leaching, and Fe removal rates were 99% and 60%, whereas Cu removal rates were 5% and 7% in the bacteria and sulfuric acid leaching solutions, respectively. After electrowinning was examined in these leaching solution, the recovery rates of Cu were obtained 98% in bacteria and obtained 76% in the sulfuric leaching solution. The dendritic form of metallic copper powder was recovered in both leaching solutions.

Preparation of Cu-Ag Powder having Core-Shell Structure by Electroless Plating Method (무전해 도금법을 이용한 코어 셸 구조의 Cu-Ag분말 제조)

  • Kim, Jong-Wan;Lee, Huk-Hee;Won, Chang-Whan
    • Journal of Surface Science and Engineering
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    • v.42 no.1
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    • pp.47-52
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    • 2009
  • Cu-Ag powder having Core-Shell structure was prepared from by electroless plating method using agents such as $AgNO_3$, $NH_{4}OH$, Hydroquinone. Ag coated copper powders were analyzed using scanning electron microscopy(SEM) and energy dispersive X-ray spectrometer(EDX). The silver coating layer of copper powder was affected from various reaction conditions such as molar ratio of $NH_{4}OH$, $AgNO_3$, and pulp density. Free silver was generated below 0.1M or 0.3M and above of $NH_{4}OH$ mole ratio. Silver coating layer thickened as addition of $AgNO_3$. When the pulp density reached 12% with 0.2M $NH_{4}OH$, and 0.15M $AgNO_3$ at $4^{\circ}C$, silver was homogeneously distributed around the copper particles and free silver particles were not generated.

Synthesis of Nano-Sized Cu Powder by PVA Solution Method and Thermal Characteristics of Sintered Cu Powder Compacts (PVA 용액법을 통한 나노 Cu 분말합성 및 소결체의 열적 특성)

  • Oh, Bok-Hyun;Ma, Chung-Il;Lee, Sang-Jin
    • Korean Journal of Materials Research
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    • v.30 no.2
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    • pp.93-98
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    • 2020
  • Effective control of the heat generated from electronics and semiconductor devices requires a high thermal conductivity and a low thermal expansion coefficient appropriate for devices or modules. A method of reducing the thermal expansion coefficient of Cu has been suggested wherein a ceramic filler having a low thermal expansion coefficient is applied to Cu, which has high thermal conductivity. In this study, using pressureless sintering rather than costly pressure sintering, a polymer solution synthesis method was used to make nano-sized Cu powder for application to Cu matrix with an AlN filler. Due to the low sinterability, the sintered Cu prepared from commercial Cu powder included large pores inside the sintered bodies. A sintered Cu body with Zn, as a liquid phase sintering agent, was prepared by the polymer solution synthesis method for exclusion of pores, which affect thermal conductivity and thermal expansion. The pressureless sintered Cu bodies including Zn showed higher thermal conductivity (180 W/m·K) and lower thermal expansion coefficient (15.8×10-6/℃) than did the monolithic synthesized Cu sintered body.

Manufacturing and Characterization of $CuInS_2$ Nanopowder for Compound Thin Film Solar Cell (화합물 박막 태양전지 적용을 위한 $CuInS_2$ 나노분말의 제조 및 특성 평가)

  • Lee, Dae-Girl;Lee, Nam-Hee;Oh, Hyo-Jin;Yun, Yeong-Ung;Hwang, Jong-Sun;Kim, Sun-Jae
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.2113_2114
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    • 2009
  • Chalcopyrite based sollar cells have received much attention because of their tunable electronic and optical properties. As a typical ternary chalcopyrite material, $CuInS_2$ has been considered as one of the most popular and promising candidates as absorber materials for photovoltaic applications because of its high absorption coefficient and environmental consideration. In this study, $CuInS_2$ powders have been synthesized using polyol process of a mixture of copper nitrate, indium nitrate, and thiourea with various stoichiometric molar ratios in ethylene glycol at $196^{\circ}C$. As boiling time goes by, the color of metal ion mixed solutions were changed transparent green to dark green and finally turned to black by reduction of OH- radicals. The prepared powders were fully characterized using SEM, XRD. The particle shape of black colored powders showed sphere with about 50 nm in particle size compared to those with dark green colored powders showed irregular shape with about $1{\mu}m$ in particle size. The XRD results showed highly crystallized $CuInS_2$.

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Hydroxyl Radical-Generating Function of Horseradish Cu,Zn-Superoxide Dismutase

  • Eum, Won-Sik;Kwon, Oh-Bin;Kang, Jung Hoon
    • BMB Reports
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    • v.31 no.5
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    • pp.492-497
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    • 1998
  • Cu,Zn-superoxide dismutase (SOD) was purified from horseradish by using Mono Q and Superose 12 FPLC column chromatography. The native molecular mass of the purified enzyme was approximately 33 kDa, as determined by gel filtration. The subunit molecular weight, as estimated by SDS-PAGE, was 16 kDa. These results indicated that the native enzyme is a homodimer. We investigated the free radical-generating function of horseradish Cu,Zn-SOD by using a chromogen, 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonate) (ABTS) which reacts with ${\cdot}OH$ radicals to form $ABTS^{+{\cdot}}$ The formation of $ABTS^{+{\cdot}}$ was required for both active Cu, Zn-SOD and $H_2O_2$. The optimal pH for the free radical-generating activity of this enzyme was 6.0-8.0, and it retained about $40^{\circ}C$ of its maximum activity when exposed at $40^{\circ}C$ for 15 min. A neutral scavenger, ethanol, inhibited the $ABTS^{+{\cdot}}$ formation by horseradish Cu, Zn-SOD more effectively than that by the mammalian enzyme. These results suggest that the active channel of horseradish enzyme is slightly larger than that of the mammalian enzyme.

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Spectroscopic and Morphological Investigation of Copper Oxide Thin Films Prepared by Magnetron Sputtering at Various Oxygen Ratios

  • Park, Ju-Yun;Lim, Kyoung-A;Ramsier, Rex D.;Kang, Yong-Cheol
    • Bulletin of the Korean Chemical Society
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    • v.32 no.9
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    • pp.3395-3399
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    • 2011
  • Copper oxide thin films were synthesized by reactive radio frequency magnetron sputtering at different oxygen gas ratios. The chemical and physical properties of the thin films were investigated by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD). XPS results revealed that the dominant oxidation states of Cu were $Cu^0$ and $Cu^+$ at 0% oxygen ratio. When the oxygen ratios increased above 5%, Cu was oxidized as CuO as detected by X-ray induced Auger electron spectroscopy and the $Cu(OH)_2$ phase was confirmed independent of the oxygen ratio. The valence band maxima were $1.19{\pm}0.09$ eV and an increase in the density of states was confirmed after formation of CuO. The thickness and roughness of copper oxide thin films decreased with increasing oxygen ratio. The crystallinity of the copper oxide films changed from cubic Cu through cubic $Cu_2O$ to monoclinic CuO with mean crystallite sizes of 8.8 nm (Cu) and 16.9 nm (CuO) at the 10% oxygen ratio level.

Preparation of nanocrystalline CuO powders by hydrazine method and their gas sensing characteristics (Hydrazine 법에 의한 CuO 미분말의 합성 및 가스 감응성 평가)

  • Kim, Sun-Jung;Lee, Jong-Heun
    • Journal of Sensor Science and Technology
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    • v.16 no.1
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    • pp.11-16
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    • 2007
  • CuO is an important transition metal oxide with many practical applications such as catalysts, p-type semiconductor, solar cells, magnetic storage media and cathode materials. In this contribution, nanocrystalline CuO powders were prepared by solution reduction method using copper chloride ($CuCl_{2}{\cdot}2H_{2}O$), hydrazine ($N_{2}H_{4}$) and NaOH and subsequent heat treatment. The gas sensor using nanocrystalline CuO powders showed high sensitivities to acetone and ethanol.