• Title/Summary/Keyword: Fe nanopowder

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Preparation and Sintering Behavior of Fe Nanopowders Produced by Plasma Arc Discharge Process

  • Choi, Chul-Jin;Yu, Ji-Hun
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.284-285
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    • 2006
  • The nano-sized Fe powders were prepared by plasma arc discharge process using pure Fe rod. The microstructure and the sintering behavior of the prepared nanopowders were evaluated. The prepared Fe nanopowders had nearly spherical shapes and consisted of metallic core and oxide shell structures. The higher volume shrinkage at low sintering temperature was observed due to the reduction of surface oxide. The nanopowders showed 6 times higher densification rate and more significant isotropic shrinkage behavior than those of micron sized Fe powders.

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Electrodeposition of Permalloy-Silica Composite Coating (전기도금법을 이용한 퍼멀로이-실리카 복합도금)

  • Jung, Myung-Won;Kim, Jong-Hoon;Lee, Heung-Yeol;Lee, Jae-Ho
    • Journal of the Microelectronics and Packaging Society
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    • v.17 no.4
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    • pp.83-88
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    • 2010
  • 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. 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 sonication time. Longer sonication period guaranteed better silica nanopowder dispersion and sonication period also influenced on composition of deposits. The amount of silica nanopowder codeposition and surface morphologies were influenced with variation of additives. In alkaline bath, smooth surface morphology and relatively high contents of silica nanopowder codeposition were obtained with addition of sodium lauryl sulfate.

Synthesis and Characteristics of W-Ni-Fe Nanocomposite Powder by Hydrogen Reduction of Oxides (산화물 수소환원에 의한 W-Ni-Fe 나노복합분말의 합성과 특성)

  • 이창우;윤의식;이재성
    • Journal of Powder Materials
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    • v.8 no.1
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    • pp.49-54
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    • 2001
  • The synthesis and characteristics of W-Ni-Fe nanocomposite powder by hydrogen reduction of ball milled W-Ni-Fe oxide mixture were investigated. The ball milled oxide mixture was prepared by high energy attrition milling of W blue powder, NiO and $Fe_2O_3$ for 1 h. The structure of the oxide mixture was characteristic of nano porous agglomerate composite powder consisting of nanoscale particles and pores which act as effective removal path of water vapor during hydrogen reduction process. The reduction experiment showed that the reduction reaction starts from NiO, followed by $Fe_2O_3$ and finally W oxide. It was also found that during the reduction process rapid alloying of Ni-Fe yielded the formation of $\gamma$-Ni-Fe. After reduction at 80$0^{\circ}C$ for 1 h, the nano-composite powder of W-4.57Ni-2.34Fe comprising W and $\gamma$-Ni-Fe phases was produced, of which grain size was35nm for W and 87 nm for $\gamma$-Ni-Fe, respectively. Sinterability of the W heavy alloy nanopowder showing full density and sound microstructure under the condition of 147$0^{\circ}C$/20 min is thought to be suitable for raw material for powder injection molding of tungsten heavy alloy.

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The Optimization of Hydrogen Reduction Process for Mass Production of Fe-8wt%Ni Nanoalloy Powder

  • Jung, Sung-Soo;Kang, Yun-Sung;Lee, Jai-Sung
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.1331-1332
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    • 2006
  • The present investigation has attemped to optimize hydrogen reduction process for the mass production of Fe-8wt%Ni nanoalloy powder from ball milled $Fe_2O_3-NiO$ powder. In-situ hygrometry study was performed to monitor the reduction behavior in real time through measurement of water vapor outflowing rate. It was found that the reduction process can be optimized by taking into account the apparent influence of water vapor trap in the reactor on reduction kinetics which strongly depends on gas flow rate, reactor volume and reduction.

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Rapid Sintering of FeAl by Pulsed Current Activated Heating and its Mechanical Properties (펄스 전류 활성 가열에 의한 나노구조의 FeAl 급속소결과 기계적 성질)

  • Jo, Seung-Hoon;Ko, In-Yong;Doh, Jung-Mann;Yoon, Jin-Kook;Shon, In-Jin
    • Korean Journal of Metals and Materials
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    • v.48 no.7
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    • pp.639-643
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    • 2010
  • Nanopowder of FeAl was synthesized by high energy ball milling. Using the pulsed current activated sintering method, a dense nanostuctured FeAl was consolidated within 2 minutes from mechanically synthesized powders of FeAl and horizontally milled powders of Fe+Al. The grain size and hardness of FeAl sintered from horizontally milled Fe+Al powders and high energy ball milled FeAl powder were 150 nm, 50 nm and $466\;kg/mm^2$, $574\;kg/mm^2$, respectively.

Microstructure and Sintering Behavior of Injection Molded Fe Sintered Body Using Rapid Thermal Heating Process (급속승온공정을 이용한 사출성헝된 Fe 소결체의 미세조직 및 소결거동)

  • Kim Ki-Hyun;Han Jae-Kil;Yu Ji-Hun;Choi Chul-Jin;Lee Byong-Taek
    • Journal of Powder Materials
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    • v.11 no.6 s.47
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    • pp.528-534
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    • 2004
  • Using the nano Fe powders having 50 nm in diameter, Fe compact bodies were fabricated by injec-tion molding process. The relationship between microstructure and material properties depending on the volume ratio of powder/binder and sintering temperature were characterized by SEM, TEM techniques. In the compact body with the volume percentage ratio of 45(Fe powder) : 55(binder), which was sintered at $700^{\circ}C,$ the relative density was about $97{\%},$ and the values of volume shrinkage and hardness were about $66.3{\%}$ and 242.0 Hv, respec-tively. Using the composition of 50(Fe powder) : 50(binder) and sintered at $700^{\circ}C,$ the values of relative density, volume shrinkage and hardness of Fe sintered bodies were $73.3{\%},\;47.6{\%}$ and 152.8 Hv, respectively. They showed brittle fracture mode due to the porous and fine microstructure.

Characteristics of Fe-Ni Nanopowders Prepared by Electrical Explosion of Wire in Water and Ethanol

  • Bac, L.H.;Kim, B.K.;Kim, J.S.;Kim, J.C.
    • Journal of Magnetics
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    • v.16 no.4
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    • pp.435-439
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    • 2011
  • In this work, we prepared Fe-Ni alloy nanopowders by wire electrical explosion in deionized water and ethanol. Particles size and morphology of the as-synthesized nanoparticles prepared in water and ethanol were observed by transmission electron microscopy. In both cases, the as-synthesized nanoparticles were in nearly spherical shape and their size distribution was broad. The particles prepared in the water were in core-shell structure due to the oxidation of Fe element. X-ray diffraction was used to analyze the phase of the nanopowders. It showed that the nanopowders prepared in water had ${\gamma}$-Fe-Ni solid solution and FeO phase. The samples obtained in ethanol were in two phases of Fe-Ni solid solution, ${\gamma}$-Fe-Ni and ${\alpha}$-Fe-Ni. Bulk samples were made from the as-synthesized nanopowders by spark plasma sintering at $1000^{\circ}C$ for 10 min. Structure of the bulk sample was observed by scanning electron microscope. Magnetic properties of the as-synthesized nanopowders and the bulk samples were investigated by vibrating sample magnetometer. The hysteresis loop of the assynthesized nanopowders and the sintered bulk samples revealed a ferromagnetic characteristic.

Characteristics of Fe Nano Powders Synthesized by Plasma Arc Discharge Process (플라즈마 아크 방전법으로 제조된 Fe 나노분말의 특성)

  • Park Woo-Young;Youn Cheol-Su;Yu Ji-Hun;Oh Young-Woo;Choi Chul-Jin
    • Korean Journal of Materials Research
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    • v.14 no.7
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    • pp.511-515
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    • 2004
  • Fe nano powders were synthesized by plasma arc discharge (PAD) process and studied by means of X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). Pure Fe rod($99.9\%$) was used as a source of metallic vapor under argon and hydrogen mixed atmosphere. The synthesized Fe nano powders had nearly spherical shapes and core-shell type structures. The influence of process parameters on the structure and size was investigated. The powder size increased with increasing of the chamber pressure and input current. High hydrogen gas ratio in chamber atmosphere affected the particle size and amount of Fe nanopowder.

Fabrication of Nanostructured $5Cu_{0.6}Fe_{0.4}-Al_2O_3$ Composite by Pulsed Current Activated Sintering from Mechanically Synthesized Powder (기계적으로 합성한 분말로부터 펄스전류 활성 소결에 의한 나노구조 $5Cu_{0.6}Fe_{0.4}-Al_2O_3$ 복합재료제조)

  • Park, Na-Ra;Song, Jun-Young;Nam, Kee-Seok;Shon, In-Jin
    • Journal of the Korean Society for Heat Treatment
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    • v.22 no.3
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    • pp.149-154
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    • 2009
  • Dense $5Cu_{0.6}Fe_{0.4}-Al_2O_3$ composite was consolidated from mechanically synthesized powders by pulsed current activated sintering method within 1 min. $5Cu_{0.6}Fe_{0.4}-Al_2O_3$ powder was synthesized from 3CuO and 2FeAI using the high energy ball milling. Dense $5Cu_{0.6}Fe_{0.4}-Al_2O_3$ with relative density of up to 95% was produced under simultaneous application of a 80 MPa pressure and the pulsed current. Mechanical properties and grain size of the composite were investigated.