• Title/Summary/Keyword: Fe nanopowder

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Influence of Grain Growth Inhibitors and Co in Nano WC Materials (나노 텅스텐 카바이드 재료 내 입성장 억제제와 코발트의 영향)

  • Lim, Hyung Sup;Hur, Man Gyu;Kim, Deug Joong;Yoon, Dae Ho
    • Journal of the Korean Ceramic Society
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    • v.51 no.5
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    • pp.442-446
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    • 2014
  • Influences of Co and inhibitors from nano-sized WC materials were observed in the sintering process. VC and $Cr_3C_2$ were used as inhibitors. The crystal structure and surface images of sintered nano-sized WC materials, as functions of Co and inhibitors, were evaluated by XRD and FE-SEM analyses. The relative densities of sintered nano-sized WC materials did not change even with increased quantity of Co and increased temperature. The density of sintered nano-sized WC materials with inhibitors was lower than that of sintered nano-sized WC materials without inhibitors. No difference in hardness due to change of inhibitors was found.

Dispersion Method of Silica Nanopowders for Permalloy Composite Coating (퍼멀로이 합금도금을 위한 나노실리카 분산방법에 관한 연구)

  • Park, So-Yeon;Jung, Myung-Won;Lee, Jae-Ho
    • Journal of the Microelectronics and Packaging Society
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    • v.18 no.4
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    • pp.39-42
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    • 2011
  • The composite electroplating is accomplished by adding inert materials during the electroplating. Permalloy is the term for Ni-Fe alloy and it is used for industrial applications due to its high magnetic permeability, surface wear resistance, corrosion protection. Microhardness for microdevices is enhanced after composite coating and it increases the life cycle. However, the hydroxyl group on the silica makes their surface susceptible to moisture and it causes the silica nanoparticles to be agglomerated in the aqueous solution. The agglomeration problem causes poor dispersion which eventually interrupts uniform deposition of silica nanoparticles. In this study, the dispersion of silica nanoparticles in the permalloy electroplated layer is reported with variation of additives and current densities. The optimum current density was 20 $mA/cm^2$ and the silica content was 9 at% at $50^{\circ}C$. The amount of silica nanopowder codeposition and surface morphologies were influenced with variation of additives. In the bath, smooth surface morphology and relatively high contents of silica nanopowder codeposition were obtained with addition of sodium lauryl sulfate.

Preparation of BaTiO3/Poly(vinylidene fluoride) 0-3 Composite Films for Dielectric Applications

  • Hwang, Kyu-Seog;Kang, Jong-Min;Lee, June-Ho;Hwangbo, Seung
    • Journal of Electrical Engineering and Technology
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    • v.13 no.4
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    • pp.1692-1696
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    • 2018
  • Ferroelectric $BaTiO_3$/poly(vinylidene fluoride) (PVDF) nanocomposite films were successfully prepared by mixing $BaTiO_3$ nano-particles into PVDF solution dissolved in dimethylformamide under ultrasonification. The mixture was casted onto glass petri dish and then annealed at $100^{\circ}C$ for 12 h in vacuum dry oven. Crystal structure and surface morphology of the samples were analyzed by using an X-ray diffraction analysis and a field emission-scanning electron microscope, respectively. The relative dielectric permittivity and loss tangent were determined in the frequency range of 50 Hz to 1 MHz. For the $BaTiO_3/PVDF$ nanocomposites, the entire diffraction peaks match those indicated by standard $BaTiO_3$ perovskite structure. The FE-SEM image reveals the homogeneity of the $BaTiO_3$ nanopowder distribution and also predominant 0-3 connectivity. All results show that the dielectric properties of the nanocomposite films are desirable and the fabrication technique for preparing the $BaTiO_3/PVDF$ nanocomposites has a potential in the electronic applications.

Enhanced Electromagnetic Properties of Nickel Nanoparticles Dispersed Carbon Fiber via Electron Beam Irradiation (전자선 안정화에 의한 니켈 나노 입자가 분산된 탄소섬유의 전자기적 특성 향상)

  • Lee, Yeong Ju;Kim, Hyun Bin;Lee, Seung Jun;Kang, Phil Hyun
    • Journal of Radiation Industry
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    • v.9 no.1
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    • pp.15-20
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    • 2015
  • Carbon fiber has received much attention owing to its properties, including a large surface-to-volume ratio, chemical and thermal stability, high thermal and electrical conductivity, and high mechanical strengths. In particular, magnetic nanopowder dispersed carbon fiber has been attractive in technological applications such as the electrochemical capacitor and electromagnetic wave shielding. In this study, the nickel-oxide-nanoparticle dispersed polyacrylonitrile (PAN) fibers were prepared through an electrospinning method. Electron beam irradiation was carried out with a 2.5 MeV beam energy to stabilize the materials. The samples were then heat-treated for stabilization and carbonization. The nanofiber surface was analyzed using a field emission scanning electron microscope (FE-SEM). The crystal structures of the carbon matrix and nickel nanopowders were analysed using X-ray diffraction (XRD). In addition, the magnetic and electrical properties were analyzed using a vibrating sample magnetometer (VSM) and 4 point probe. As the irradiation dose increases, the density of the carbon fiber was increased. In addition, the electrical properties of the carbon fiber improved through electron beam irradiation. This is because the amorphous region of the carbon fiber decreases. This electron beam effect of PAN fibers containing nickel nanoparticles confirmed their potential as a high performance carbon material for various applications.

A Study on the Characteristics of Silicon Nanopowders Produced by Transferred Type Arc Plasma Apparatus (이송식 아크플라즈마 장치에 의해 제조된 실리콘 나노분말의 특성에 대한 연구)

  • Kan, Woo-Seop;Park, Sang-Hee
    • Journal of the Korean Society of Industry Convergence
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    • v.24 no.6_2
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    • pp.909-917
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    • 2021
  • This study was carried out experimentally on the production and properties of silicon nanopowders characteristics using a transferred type arc plasma apparatus. To investigate the properties of silicon nanopowder, the purity of argon gas(99.999%, 99.9%) and the partial pressure ratio of nitrogen gas(0~90%) were varied. The total pressure in chamber is 400Torr and the silicon chunk amount used as raw material is 300g. The power supplied to the cathode to generate arc plasma was 9~12kW/h, and the electrode was made of tungsten and graphite with a diameter of 13mm. The particle size, impurity elements and powder evaporation rate of the silicon powder were analyzed using the XRD, FE-SEM, TEM and electronic scale. According to the purity of argon gas, the silicon evaporation rate and the particle size were similar, and impurities were generated more in the case of 99.9% purity than 99.999%. When argon gas and nitrogen gas were mixed in the chamber, the silicon evaporation rate and particle size increased as the partial pressure ratio of nitrogen gas increased. In particular, when the partial pressure ratio of nitrogen gas was 80%, the silicon evaporation rate 80g/h, and the particle size was about 80~100nm.