Journal of Powder Materials

Biomedical Applications of Magnetic Nanoparticles: J Korean Powder Metall Inst. 2002;9(3):141-147.; DOI: https://doi.org/10.4150/KPMI.2002.9.3.141

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An Effectiveness of Radio Frequcncy(RF) Shielding Fibers and Customized RF Protective Clothing Applied to the Whole Body in Partial Area Imaging Working as a RF Absorber
Lucia Kang, Kwanwoo Choi, Hobeom Lee, Sara Na, Seonwook Yang, Daekeon Seo
Journal of the Korean Society of MR Technology.2017; 27(2): 45. CrossRef
Applicability of radioactive99mTc-O4−magnetic fluid to nuclear medicine
Jong-Hee Kim, Seong-Min Kim, Keun-Ho Kim, Chong-Oh Kim
Journal of Physics: Conference Series.2011; 266: 012073. CrossRef
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Eunsook Seo
SSRN Electronic Journal .2008;[Epub] CrossRef
Fabrication of SiO₂-Coated Magnetic Nanoparticles for Applications to Protein Separation and Purification
S.H. Yun, C.W. Lee, Jai Sung Lee, C.W. Seo, E.K. Lee
Materials Science Forum.2004; 449-452: 1033. CrossRef

Microstructures and Fracture Characteristic of Pressureless-Sintered DyNbO₄ body: J Korean Powder Metall Inst. 2002;9(3):148-152.; DOI: https://doi.org/10.4150/KPMI.2002.9.3.148

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Abstract PDF: The microstructures and indentation fracture of pressureless-sintered DyNbO_4 crystalline were investigated as a basic study for the application of weak phase of fibrous monolithic composites. They were comprised with many lamella twins as well as micro-cracks at the grain boundaries. The hardness at room temperature was remarkably low value(575 Hv) due to the low relative density and existence of microcracks at grain boundaries. The main fracture mode was a typical intergranular fracture, and showed remarkable micro-cracking effect. The heavy plastic deformation was observed around the site of indentation. In addition, the DyNbO_4 was expected to apply as a weak phase in the fibrous monolithic composites because of the low hardness and easily plastic deformation that could be led the preferable pulled-out and microcracking toughening under the failure.

Microstructure and Mechanical Property of Aluminum Powder Compact by Powder-in Sheath Rolling Method: J Korean Powder Metall Inst. 2002;9(3):153-160.; DOI: https://doi.org/10.4150/KPMI.2002.9.3.153

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A nitrogen gas atomized aluminum powder was consolidated by powder-in sheath rolling method. A pure aluminum tube with outer diameter of 12 mm and wall thickness of 1mm was used as a sheath. The aluminum tube filled with the aluminum powder, first, was cold-rolled to the thickness of 6mm for performing, and then consolidated by the cold rolling and/or subsequent hot rolling at 360, 460 and 560°C. The aluminum powder compact fabricated by the sheath rolling showed high relative density more than 0.96 at any rolling conditions. The 0.2% proof stress increased with increasing hot rolling reduction and hot rolling temperature. Tensile strength was hardly affected by change in the hot rolling reduction, whereas it decreased with increasing hot rolling temperature. The powder compact showed the large elongation when cold rolling or hot rolling reduction was large. It was found that the sheath rolling was an effective method for consolidation of aluminum powder.

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Microstructure and Mechanical Properties of CNT/Al Composite Fabricated by a Powder-in-Sheath Rolling Method utilizing Copper Tube as a Sheath
Seong-Hee Lee
Journal of Korean Powder Metallurgy Institute.2014; 21(5): 343. CrossRef

Microstructure and Properties of Nano-Sized Ni-Fe Alloy Dispersed Al₂O₃ Composites: J Korean Powder Metall Inst. 2002;9(3):161-166.; DOI: https://doi.org/10.4150/KPMI.2002.9.3.161

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Abstract PDF: 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)_2cdot6H_2O and Fe(NO_3)_3cdot9H_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.

A Study On Synthesis of Nanostructured WC/Co composite Powders by Mechanochemical process: J Korean Powder Metall Inst. 2002;9(3):167-173.; DOI: https://doi.org/10.4150/KPMI.2002.9.3.167

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A new approach to produce nanostructured WC/Co composite powders by a mechanochemical process was made to improve the mechanical properties of advanced hardmetals. Homogeneous spherical W-Co salt powders were made by spray drying of aqueous solution from ammonium metatungstate((NH_4)_6(H_2W_12O_40)cdo4H_2O,AMT) and cobalt nitrate hexahydrate (Co(NO_3)_2.6H_2O). spray dried W-Co salt powders were calcined for 1 hr at 700°C in atmosphere of air. The oxide powder was mixed with carbon black by ball milling and this mixture was heated with various temperatures and times in H_2. The WO_3/CoWO_4 composite oxide powders were obtained by calcinations at 700°C. The primary particle size of W/Co composite oxide powders by SEM was 100 nm. The reduction/carburization time decreased with increasing temperatures and carbon additions. The average size of WC particle carburized at 800°C by TEM was smaller than 50 nm.

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Synthesis of WC-10wt.%Co Nanocrystalline Powders with Grain Growth Inhibitor by MTP
Dong Kyu Park, Kwang Chul Jung, Jin Chun Kim, Sung Yeal Bae, In Sup Ahn
Materials Science Forum.2007; 534-536: 1237. CrossRef

Synthesis and Microstructural Changes of Nanostructured Tungsten Carbide Powder by Chemical Vapor Condensation Process: O.V.Tolochko; J Korean Powder Metall Inst. 2002;9(3):174-181.; DOI: https://doi.org/10.4150/KPMI.2002.9.3.174

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Abstract PDF: Nanosized tungsten carbide powders were synthesized by the chemical vapor condensation(CVC) process using the pyrolysis of tungsten hexacarbonyl(W(CO)_6). The effect of CVC parameters on the formation and the microstructural change of as-prepared powders were studied by XRD, BET and TEM. The loosely agglomerated nanosized tungsten-carbide(WC_1-x) particles having the smooth rounded tetragonal shape could be obtained below 1000°C in argon and air atmosphere respectively. The grain size of powders was decreased from 53 nm to 28 nm with increasing reaction temperature. The increase of particle size with reaction temperature represented that the condensation of precursor vapor dominated the powder formation in CVC reactor. The powder prepared at 1000°C was consisted of the pure W and cubic tungsten-carbide (WC_1-x), and their surfaces had irregular shape because the pure W was formed on the WC_1-x powders. The WC_1-x and W powders having the average particles size of about 5 nm were produced in vacuum.

Fabrication and Magnetic Properties of Nanostructured Fe-Co Alloy Powder: J Korean Powder Metall Inst. 2002;9(3):182-188.; DOI: https://doi.org/10.4150/KPMI.2002.9.3.182

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Conventional Fe-Co alloys are important soft magnetic materials that have been widely used in industry. Compared to its polycrystalline counterpart, the nanostructured materials have showed superior magnetic properties, such as higher permeability and lower coercivity due to the single domain configuration. However, magnetic properties of nanostructured materials are affected in complicated manner by their microstructure such as grain size, internal strain and crystal structure. Thus, studies on synthesis of nanostructured materials with controlled microstructure are necessary for a significant improvement in magnetic properties. In the present work, starting with two powder mixtures of Fe and Co produced by mechanical alloying (MA) and hydrogen reduction process (HRP), differences in the preparation process and in the resulting microstructural characteristics will be described for the nano-sized Fe-Co alloy particles. Moreover, we discuss the effect of the microstructure such as crystal structure and grain size of Fe-Co alloys on the magnetic properties.

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Heterogeneous nucleation in the polyol process for the synthesis of FeCo alloy powders
Uk Rae Cho, Dong Gun Lee, Byung Hyun Ahn, Je Hyun Lee, Bon Heun Koo
Journal of the Korean Physical Society.2014; 64(10): 1451. CrossRef

Transient Liquid Phase Bonding of Ni-Cr Heat Resisted Cast Steel: J Korean Powder Metall Inst. 2002;9(3):189-198.; DOI: https://doi.org/10.4150/KPMI.2002.9.3.189

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Abstract PDF: In this work, transient liquid phase (TLP) bonding of Ni-Cr heat resisted cast alloy (HP) was investigated. And also the behaviors of the solid particles distributed in the interlayer during TLP bonding were investigated. The MBF-60 and solid particles (Ni, Fe, and Al_2O_3 powders respectively) added MBF-60 which will be a liquid phase coexisting with solid particles at the bonding temperature were used as insert metal. The effective and sound bonding was possible by spark plasma sinter-bonding due to the differences of electric resistance between base metal and liquid insert layer which creates high temperature region. During the isothermal solidification, Al_2O_3 particles and solid particles of liquid phase sintered insert metal have shown no growth, while Ni and Fe particles grow rapidly. In this TLP bonding using the MBF-60 and distributed Fe, Ni particles as insert materials, the whole isothermal solidification process was dominated by the growth rate of the solid particles distributed in the interlayer.

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