• 제목/요약/키워드: copper particles

검색결과 261건 처리시간 0.028초

황산동 수용액으로부터 hydrazine 환원에 의한 Cu 미립자의 합성 (Synthesis of Uniform Cu Particles by Hydrazine Reduction from Copper Sulfate Solution)

  • 유연태;최영윤
    • 한국재료학회지
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    • 제13권8호
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    • pp.524-530
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    • 2003
  • In order to prepare the uniform copper particles from copper sulfate solution by using hydrazine as a reduction agents, the reduction behavior of copper particles from copper sulfate was investigated in detail at room temperature by the observation of reaction products. The effects of $NH_4$OH and $Na_4$$P_2$$O_{7}$ on the formation of uniform copper particles were discussed. ($NHCu_3$)$_4$$SO_4$was completely formed at over pH 11 by adding $NH_4$OH in copper sulfate solution. The fine $Cu_2$O with the particle size of 50 nm was produced in the initial reduction process of (NH$Cu_3$)$_4$$SO_4$solution with $Na_4$$P_2$$O_{ 7}$ and then the Cu$_2$O was converted into copper particles by inserting additional hydrazine. When Cu(NH$_3$)$_4$SO$_4$solution with $Na_4$$P_2$$O_{ 7}$ was reduced at $80^{\circ}C$ by hydrazine, the highly dispersed copper particles with the particle size of about 0.8 $\mu\textrm{m}$ was obtained.

첨가제에 함유된 미세한 구리합금입자의 마찰 및 마모 특성 (Friction and Wear Characteristics of Copper Alloy Fine Particles Contained in an Additive)

  • 안효석;이성철
    • Tribology and Lubricants
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    • 제12권2호
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    • pp.32-40
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    • 1996
  • The tribological role of copper alloy fine particles in an additive is not well known compared to solid lubricants such as $MoS_{2}$ and PTFE. In this experimental investigation, a series of friction and wear test was undertaken to gain a better understanding of an additive containing copper alloy fine particles and to identify the effectiveness of copper alloy particles in improving tribological performance of the lubricant. Friction and wear of specimens under lubricated contact condition were studied and the worn surfaces were characterized by AES (Auger Electron Spectroscopy), SEM (Scanning Electron Microscopy) and optical microscopy. It was revealed that a copper-contained layer was formed and this layer resulted in considerable reduction in both friction and wear due to its lubricity and anti-wear property. The analysis of worn surface revealed that copper of the fine alloy particles in the additive helps healing the worn surface by plating and filling wear pits.

염화동 수용액으로부터 Cu 미립자의 합성 (Synthesis of Uniform Cu Particles from Copper Chloride Solution)

  • 윤지희;권현우;유연태;김병규;김광수
    • 한국재료학회지
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    • 제15권4호
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    • pp.263-270
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    • 2005
  • In order to prepare the uniform copper particles from copper chloride solution, the reduction behavior of copper particles from copper chloride and the effects of reduction agent and dispersing agent was investigated. In the case that 2.56 M of $C_6H_8O_6$ was used as a reduction agent, the highly dispersed Cu particles with sharp size distribution were generated from 0.96M of copper chloride solution, and the size of Cu particles was $6\~10\;{\mu}m$. To form $Cu(NH_3)_4Cl_2$ complex solution, $NH_4OH$ was added in the copper chloride solution before the reductive reaction of Cu ion. The generated Cu particles have a two kind of shape, spherical and rod-like. In the case that $N_2H_4{\cdot}H_2O$ was used as a reduction agent, the very fine spherical Cu particles with the size of $0.2\~0.5\;{\mu}m$ was obtained. Arabic gum as a dispersing agent was more effective than $Na_4P_2O_7{\cdot}10H_2O$.

1-Octanethiol이 코팅된 나노 구리 분말을 이용한 나노 잉크의 분산도에 대한 연구 (Investigation of Dispersion Stability of Conductive Nano Ink Using 1-Octanethiol Coated Copper Nano Powders)

  • 조단이;백종환;박중학;이선영
    • 한국세라믹학회지
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    • 제49권5호
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    • pp.417-422
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    • 2012
  • Copper nano particles have been considered as the materials for conductive ink due to its good thermal, electrical conductivity and low cost. However, copper nanoparticles oxidize easily, decreasing dispersion stability and electrical conductivity. Therefore, it is important to develop a method to minimize oxidation of copper nano particles to improve its dispersion stability property in copper nano ink. In this study, copper nano particles were coated with 1-Octanethiol VSAM(Vaporized Self Assembled Multilayers) to prevent oxidation and coated copper powders were dispersed in conductive ink successfully by studying its relationship of different chain length of solvents to 1-Octanethiol coating layer to fabricate nano ink. Various alcohol solvents, such as 1-Hexanol, 1-Octanol, and 1-Decanol were used. The coating layer was observed using FESEM and TEM. Furthermore, dispersion of copper nano particles in nano inks, was characterized using Turbiscan analyzer, viscometer, and contact angle measurement tool.

Synthesis of metallic copper nanoparticles and metal-metal bonding process using them

  • Kobayashi, Yoshio;Nakazawa, Hiroaki;Maeda, Takafumi;Yasuda, Yusuke;Morita, Toshiaki
    • Advances in nano research
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    • 제5권4호
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    • pp.359-372
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    • 2017
  • Metallic copper nanoparticles were synthesised by reduction of copper ions in aqueous solution, and metal-metal bonding by using the nanoparticles was studied. A colloid solution of metallic copper nanoparticles was prepared by mixing an aqueous solution of $CuCl_2$ (0.01 M) and an aqueous solution of hydrazine (reductant) (0.2-1.0 M) in the presence of 0.0005 M of citric acid and 0.005 M of n-hexadecyltrimethylammonium bromide (stabilizers) at reduction temperature of $30-80^{\circ}C$. Copper-particle size varied (in the range of ca. 80-165 nm) with varying hydrazine concentration and reduction temperature. These dependences of particle size are explained by changes in number of metallic-copper-particle nuclei (determined by reduction rate) and changes in collision frequency of particles (based on movement of particles in accordance with temperature). The main component in the nanoparticles is metallic copper, and the metallic-copper particles are polycrystalline. Metallic-copper discs were successfully bonded by annealing at $400^{\circ}C$ and pressure of 1.2 MPa for 5 min in hydrogen gas with the help of the metalli-ccopper particles. Shear strength of the bonded copper discs was then measured. Dependences of shear strength on hydrazine concentration and reduction temperature were explained in terms of progress state of reduction, amount of impurity and particle size. Highest shear strength of 40.0 MPa was recorded for a colloid solution prepared at hydrazine concentration of 0.8 M and reduction temperature of $50^{\circ}C$.

Design of Copper Alloys Preventing Grain Boundary Precipitation of Copper Sulfide Particles for a Copper Disposal Canister

  • Minkyu Ahn;Jinwoo Park;Gyeongsik Yu;Jinhyuk Kim;Sangeun Kim;Dong-Keun Cho;Chansun Shin
    • 방사성폐기물학회지
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    • 제21권1호
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    • pp.1-8
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    • 2023
  • The major concern in the deep geological disposal of spent nuclear fuels include sulfide-induced corrosion and stress corrosion cracking of copper canisters. Sulfur diffusion into copper canisters may induce copper embrittlement by causing Cu2S particle formation along grain boundaries; these sulfide particles can act as crack initiation sites and eventually cause embrittlement. To prevent the formation of Cu2S along grain boundaries and sulfur-induced copper embrittlement, copper alloys are designed in this study. Alloying elements that can act as chemical anchors to suppress sulfur diffusion and the formation of Cu2S along grain boundaries are investigated based on the understanding of the microscopic mechanism of sulfur diffusion and Cu2S precipitation along grain boundaries. Copper alloy ingots are experimentally manufactured to validate the alloying elements. Microstructural analysis using scanning electron microscopy with energy dispersive spectroscopy demonstrates that Cu2S particles are not formed at grain boundaries but randomly distributed within grains in all the vacuum arc-melted Cu alloys (Cu-Si, Cu-Ag, and Cu-Zr). Further studies will be conducted to evaluate the mechanical and corrosion properties of the developed Cu alloys.

액상프리커서법에 의한 산화구리(CuO) 나노 입자의 합성 (Synthesis of CuO nanoparticles by liquid phase precursor process)

  • 신성환
    • 문화기술의 융합
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    • 제9권6호
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    • pp.855-859
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    • 2023
  • 질산구리삼수화물염(copper(II) nitrate trihydrate) 수용액을 공업용 전분(starch)에 함침 시킨 전구체를 이용하여 산화구리(CuO) 나노 입자를 합성하였다. 주사전자현미경(SEM)을 통하여 질산구리삼수화물염 수용액이 함침된 전구체에 대한 구조를 분석하였고, 전구체에 대한 열처리 온도를 증가 시킴에 따라 생성되는 산화구리 입자의 입자 크기와 결정 구조를 X선회절분석법(XRD)과 주사전자현미경(SEM)으로 분석하였다. 분석 결과에 따르면, 전구체에서 유기물질이 완전히 열분해 되어지는 온도는 450-490℃이며, 열처리하는 온도가 증가함에 따라 생성되는 산화구리 입자의 크기와 결정성이 증가하는 것을 확인할 수 있었고, 또한 500-800℃에서 1시간씩 열처리하여 얻은 산화구리 입자의 크기는 100nm-2㎛인 것으로 나타났다. 하소 온도 400℃에서 산화구리 결정상이 형성되고, 800℃까지는 산화구리 단일상만 존재하며, 하소 온도의 증가에 따라 생성되는 입자의 크기가 커지는 것을 확인하였다.

동정광 입자의 산화반응에 관한 속도론적 연구 (Kinetic Studies on the Oxidation of Copper Concentrate Particles)

  • 손호상
    • 자원리싸이클링
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    • 제11권6호
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    • pp.47-54
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    • 2002
  • 내경 2.8cm, 높이 65cm의 반응관을 이용하여 1000∼1400 K에서 산소-질소 혼합 가스류 중을 낙하하는 동정광 입자의 1차원 비등온 산화반응의 초기거동에 대하여 검토하였다. 동 정광은 반응관을 낙하하면서 매우 빠르게 산화 용융되었다. 입자 온도는 미 반응핵 모델과 가스-입자간의 물질전달 및 가스-입자-관벽 사이의 열전달을 조합하여 계산하였다. 계산에 의한 입자 온도는 반응관 상단에서 20∼30cm의 위치에서 최고온도에 도달하였으며, 고 산소분압에서는 약 1700 K에 도달하였다. 산소분압이 0.2 atm 이상인 경우 대부분의 입자는 용융되었다.

CeO2 코팅을 통한 Cu 입자의 입성장 억제 효과에 관한 연구 (Effect of CeO2 Coating on the Grain Growth of Cu Particles)

  • 유희준;문지웅;오유근;문주호;황해진
    • 한국분말재료학회지
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    • 제12권6호
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    • pp.413-421
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    • 2005
  • Copper is able to work as a current collector under wide range of hydrocarbon fuels without coking in Solid oxide fuel cells (SOFCs). The application of copper in SOFC is limited due to its low melting point, which result in coarsening the copper particle. This work focuses on the sintering of copper powder with ceria coating layer. Ceria-coated powder was prepared by thermal decomposition of urea in $Ce(NO_3)_3\cdot6H_2O$ solution, which containing CuO core particles. The ceria-coated powder was characterized by XRD, ICP, and SEM. The thermal stability of the ceria-coated copper in fuel atmosphere $(H_2)$ was observed by SEM. It was found that the ceria coating layer could effectively hinder the grain growth of the copper particles.

구리 나노 입자가 함침된 PTFE의 윤활 마모 거동 (Tribological Wear Behavior of PTFE Impregnated with Cu Nano Particles)

  • 김시영;김은봉;콴유;주창식
    • 동력기계공학회지
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    • 제14권4호
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    • pp.50-55
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    • 2010
  • In order to investigate tribological effects of nano copper particles impregnated(CuN) on surface polytetrafluoroethylene(PTFE) on sealing wear and an experimental study was carried out to determine the wear behavior of copper nano-particles impregnation two kind thickness in super critical $CO_2$ liquid. Experimental results showed that the friction coefficients of CuN PTFE at the low sliding speed(0.44m/s) and the oil temperature ($60^{\circ}C$) were higher than that of virgin PTFE. And a thin nano copper particles impreganated thickness was formed on the surface in the PTFE and the specimen with this treatment has much better friction properties than the original one. Fortunately, at the high load(80 N) and the oil temperature, the friction coefficient of CuN PTFE was lower than that of virgin PTFE. This evidenced the load carrying capacity of CuN PTFE was much better than that of virgin PTFE under the high load condition(80 N) specially. Therefore, it can be concluded that the friction coefficient variation of CuN PTFE is very small but its wear rate decreases greatly with increase in sliding speed.