• Title/Summary/Keyword: Fe powder

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Synthesis and Characteristics of FePt Nanopowder by Chemical Vapor Condensation Process

  • Yu, Ji-Hun;Lee, Dong-Won;Kim, Byoung-Kee;Jang, Tae-Suk
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.1196-1197
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    • 2006
  • FePt binary-alloy nanopowder has been successfully synthesized by chemical vapor condensation process with two metal organic precursors, i.e., iron pentacarbonyl and platinum acetylacetonate. Average particle size of the powder was less than 50 nm with very narrow size distribution, revealing high dispersion capability. Characteristics of the powder could be controlled by changing process parameters such as reaction temperature, chamber pressure, as well as gas flow rate. Magnetic properties of the synthesized FePt nanopowder were investigated and analyzed in terms of the powder characteristics.

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Microstructure and Properties of Nano-Sized Ni-Fe Alloy Dispersed Al2O3 Composites (Ni-Fe 합금입자 분산 Al2O3 나노복합재료의 미세조직 및 특성)

  • 남궁석;정재영;오승탁;이재성;이홍재;정영근
    • Journal of Powder Materials
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    • v.9 no.3
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    • pp.161-166
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    • 2002
  • Processing and properties of $Al_2O_3$ composites with Ni-Fe content of 10 and 15 wt% were investigated. Homogeneous powder mixtures of $Al_2O_3$/Ni-Fe alloy were prepared by the solution-chemistry route using $Al_2O_3$, $Ni(NO_3)_2{\cdot}6H_2O$ and $Fe(NO_3)_3{\cdot}9H_2O$ powders. Microstructural observation of composite powder revealed that Ni-Fe alloy particles with a size of 20nm were homogeneously dispersed on $Al_2O_3$ powder surfaces. Hot-pressed composites showed enhanced fracture toughness and magnetic response. The properties are discussed based on the observed microstructural characteristics.

Magnetic Properties of Amorphous FeSiB and Nanocrystalline $Fe_{73}Si_{16}B_7Nb_3Cu_1$ Soft Magnetic Sheets

  • Cho, H.J.;Cho, E.K.;Song, Y.S.;Kwon, S.K.;Sohn, K.Y.;Park, W.W.
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.786-787
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    • 2006
  • The magnetic inductance of nanocrystalline $Fe_{73}Si_{16}B_7Nb_3Cu_1$ and an amorphous FeSiB powder sheet has been investigated to identify RFID performance. The powder was mixed with binder and solvent and tape-casted to form films. Results show annealing significantly influenced on the inductance of the material. The surface oxidation of the particles was the main reason for the reduced inductance. The maximum inductance of $Fe_{73}Si_{16}B_7Nb_3Cu_1$ alloy was about $88{\mu}H$ at 17.4 MHz, about 65% greater compared to the FeSiB alloy. The higher inductance in the nanocrystalline alloy indicates it may be used as a potential replacement of current RFID materials.

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Microstructural Characterization of Gas Atomized Copper-Iron Alloys with Composition and Powder Size

  • Abbas, Sardar Farhat;Kim, Taek-Soo
    • Journal of Powder Materials
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    • v.25 no.1
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    • pp.19-24
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    • 2018
  • Cu-Fe alloys (CFAs) are much anticipated for use in electrical contacts, magnetic recorders, and sensors. The low cost of Fe has inspired the investigation of these alloys as possible replacements for high-cost Cu-Nb and Cu-Ag alloys. Here, alloys of Cu and Fe having compositions of $Cu_{100-x}Fe_x$ (x = 10, 30, and 50 wt.%) are prepared by gas atomization and characterized microstructurally and structurally based on composition and powder size with scanning electron microscopy (SEM) and X-ray diffraction (XRD). Grain sizes and Fe-rich particle sizes are measured and relationships among composition, powder size, and grain size are established. Same-sized powders of different compositions yield different microstructures, as do differently sized powders of equal composition. No atomic-level alloying is observed in the CFAs under the experimental conditions.

Preparation of gas-atomized Fe-based alloy powders and HVOF sprayed coatings

  • Chau, Joseph Lik Hang;Pan, Alfred I-Tsung;Yang, Chih-Chao
    • Advances in materials Research
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    • v.6 no.4
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    • pp.343-348
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    • 2017
  • High-pressure gas atomization was employed to prepare the Fe-based $Fe_{50}Cr_{24}Mo_{21}Si_2B_3$ alloy powder. The effect of flow rate of atomizing gas on the median powder diameter was studied. The results show that the powder size decreased with increasing the flow rate of atomizing gas. Fe-based alloy coatings with amorphous phase fraction was then prepared by high velocity oxygen fuel spraying (HVOF) of gas atomized $Fe_{50}Cr_{24}Mo_{21}Si_2B_3$ powder. Microstructural studies show that the coatings present dense layered structure and low porosity of 0.17% in about $200{\mu}m$ thickness. The Fe-based alloy coating exhibits an average hardness of about 1230 HV. Our results show that the HVOF process results in dense and well-bonded coatings, making it attractive for protective coatings applications.

Microstructure and Magnetic Properties of Nanostructured Fe-Co Alloy Powders Produced by Chemical Solution Mixing and Hydrogen Reduction Methods (화학용액혼합과 수소환원법으로 제조된 나노 구조 Fe-Co 합금분말의 미세구조 및 자성 특성)

  • 박현우;이백희;이규환;김영도
    • Journal of Powder Materials
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    • v.10 no.5
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    • pp.333-336
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    • 2003
  • The purpose of this study is the fabrication of nano-sized Fe-Co alloy powders with soft magnetic properties by the slurry mixing and hydrogen reduction (SMHR) process. $FeCl_2$0 and $CoCl_2$ powders with 99.9% purities were used for synthesizing nanostructured Fe-Co alloy powder. Nano-sized Fe-Co alloy powders were successfully fabricated using SMHR, which was performed at 50$0^{\circ}C$ for 1 h in H$_2$ atmosphere. The fabricated Fe-Co alloy powders showed $\alpha$' phase (ordered body centered cubic) with the average particle size of 45 nm. The SMHR powder exhibited low coercivity force of 32.5 Oe and saturation magnetization of 214 emu/g.

Sintering Behavior of the Injection Molded W-Ni-Fe Heavy Alloy by Addition of Metallic Stat (금속 염 첨가 방법을 이용하여 사출성형된 텅스텐 중합금의 소결거동)

  • 김대건;류성수;김은표;이정근;김영도;문인형
    • Journal of Powder Materials
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    • v.6 no.4
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    • pp.294-300
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    • 1999
  • This study was carried out to investigate the possibility whether Metal Injection Molding (MIM) process could be applied to 95wt.%W-3.5wt.%Ni-1.5wt.%Fe heavy alloy in order to obtain an intricate shape. Methylcellulose was used in the injection molding for binder. $FeCl_2-4H_2O$ was added in solvent substituting Fe powder and $FeCl_2$ was doped on W-Ni premixed powder. When $FeCl_2-4H_2O$ was added in solvent, the binder separation occurred for injection molding so that the matrix content was changed. Such problem was solved when $FeCl_2$ was doped. In this study. the debinding process did not affect residual carbon content. The sintered microsouctures as addition methods of Fe element and the sintering temperature from $1420^{\circ}C$ to $1470^{\circ}C$, which are around the temperature of liquid phase formation, were observed.

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Magnetic and Photo-catalytic Properties of Nanocrystalline Fe Doped $TiO_2$ Powder Synthesized by Mechanical Alloying

  • Uhm, Y.R.;Woo, S.H.;Lee, M.K.;Rhee, C.K.
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.955-956
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    • 2006
  • Fe-doped $TiO_2$ nanopowders were prepared by mechanical alloying (MA) varying Fe contents up to 8.0 wt.%. The UV-vis absorption showed that the UV absorption for the Fe-doped powder shifted to a longer wavelength (red shift). The absorption threshold depends on the concentration of nano-size Fe dopant. As the Fe concentration increased up to 4 wt.%, the UV-vis absorption and the magnetization were increased. The benefical effect of Fe doping for photocatalysis and ferromagnetism had the critical dopant concentration of 4 wt.%. Based on the UV absorption and magnetization, the dopant level is localized to the valence band of $TiO_2$.

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Synthesis of DyF3 paste and Magnetic Properties of GBDPed Nd-Fe-B Magnets (DyF3 paste 제조 및 이를 이용한 Nd-Fe-B 입계확산 자석의 특성 연구)

  • Jeon, Kwang-Won;Cha, Hee-Ryoung;Lee, Jung-Goo
    • Journal of Powder Materials
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    • v.23 no.6
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    • pp.437-441
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    • 2016
  • Recently, the grain boundary diffusion process (GBDP), involving heavy rare-earth elements such as Dy and Tb, has been widely used to enhance the coercivity of Nd-Fe-B permanent magnets. For example, a Dy compound is coated onto the surface of Nd-Fe-B sintered magnets, and then the magnets are heat treated. Subsequently, Dy diffuses into the grain boundaries of Nd-Fe-B magnets, forming Dy-Fe-B or Nd-Dy-Fe-B. The dip-coating process is also used widely instead of the GBDP. However, it is quite hard to control the thickness uniformity using dip coating. In this study, first, a $DyF_3$ paste is fabricated using $DyF_3$ powder. Subsequently, the fabricated $DyF_3$ paste is homogeneously coated onto the surface of a Nd-Fe-B sintered magnet. The magnet is then subjected to GBDP to enhance its coercivity. The weight ratio of binder and $DyF_3$ powder is controlled, and we find that the coercivity enhances with decreasing binder content. In addition, the maximum coercivity is obtained with the paste containing 70 wt% of $DyF_3$ powder.