Journal of Powder Materials

Dust Suppression Technology of Radioactively Contaminated Area: Hui-Jun Won, Jei-Kwon Moon, Chong-Hun Jung; J Korean Powder Metall Inst. 2007;14(2):85-96.; DOI: https://doi.org/10.4150/KPMI.2007.14.2.085

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Study of Mechanically Alloyed Nano Cu-Fe Particles With a Hetero-Structure: Y.R. Uhm, H.M. Lee, C.K. Rhee; J Korean Powder Metall Inst. 2007;14(2):97-100.; DOI: https://doi.org/10.4150/KPMI.2007.14.2.097

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Abstract PDF: The magnetic alloys of Cu-Fe (Cu_50Fe_50,;Cu_80Fe_20;and;Cu_90Fe_10) were prepared by a mechanical alloying method and their structural and magnetic behaviors were examined by X-ray diffraction and Mossbauer spectra. The magnetization curves did not distinctly show the saturation at 70 kOe for the concentrated alloys of Cu_80Fe_20;and;Cu_90Fe_10. The Mossbauer spectrum of Cu_80Fe_20 at room temperature shows one Lorentzian line of the paramagnetic phase, whereas the Mossbauer spectrum of Cu_90Fe_10 consists of sextet Lorentzian line at room temperature and a centered doublet line. The Mossbauer spectra of Cu_90Fe_10 measured in the temperature ranges from 13 to 295 K, implies that Cu_90Fe_10 to consists of two magnetic phases. One superimposed sextet corresponds to the ferromagnetic iron in Cu and the other one indicates the superparamagnetic iron rich phase.

Synthesis of Tungsten Heavy alloy Nanocomposite Powder by Ultrasonic-milling Process: Seung-Chul Lee, Chang-Woo Lee, Sung-Soo Jung, Berm-Ha Cha, Jai-Sung Lee; J Korean Powder Metall Inst. 2007;14(2):101-107.; DOI: https://doi.org/10.4150/KPMI.2007.14.2.101

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Ultrasonic-milling of metal oxide nanopowders for the preparation of tungsten heavy alloys was investigated. Milling time was selected as a major process variable. XRD results of metal oxide nanopowders ultrasonic-milled for 50 h and 100 h showed that agglomerate size reduced with increasing milling time and there was no evidence of contamination or change of composition by impurities. It was found that nanocomposite powders reduced at 800°C in a hydrogen atmosphere showed a chemical composition of 93.1W-4.9Ni-2.0Fe from EDS analysis. Hardness of sintered part using 50 h and 100 h powder samples was 399 Hv and 463 Hv, respectively, which is higher than the that of commercial products (330-340 Hv).

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Grinding behavior of WO3, NiO, Fe2O3 by ultrasonic milling parameters control and preparation of nanocomposite powder
Keunhyuk Ryu, Kun-Jae Lee
Advanced Powder Technology.2020; 31(9): 3867. CrossRef
Investigation on Size Distribution of Tungsten-based Alloy Particles with Solvent Viscosity During Ultrasonic Ball Milling Process
KeunHyuk Ryu, HyeongSub So, JiSeok Yun, InHo Kim, Kun-Jae Lee
Journal of Korean Powder Metallurgy Institute.2019; 26(3): 201. CrossRef

Cu-Ni-P Alloy Nano Powders Prepared by Electrical Wire Explosion: Won-Baek Kim, Je-Shin Park, Chang-Youl Suh, Jae-Chun Lee, Jung-Hwan Kim, Yong-Jun Oh; J Korean Powder Metall Inst. 2007;14(2):108-115.; DOI: https://doi.org/10.4150/KPMI.2007.14.2.108

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Cu-Ni-P alloy nano powders were fabricated by the electrical explosion of electroless Ni plated Cu wires. The effect of applied voltage on the explosion was examined by applying pulse voltage of 6 and 28 kV, The estimated overheating factor, K, were 1.3 for 6 kV and 2.2 for 28 kV. The powders produced with pulse voltage of 6 kV were composed of Cu-rich solid solution, Ni-rich solid solution, and Ni_3P phase. While, those produced with 28 kV were complete Cu-Ni-P solid solution and small amount of Ni_3P phase. The initial P content of 6.5 at.% was reduced to 2-3 at.% during explosion due to its high vapour pressure.

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In-Situ Characterization of Metal Nanopowders Manufactured by the Wire Electrical Explosion Process
Seung-Bok Lee, Jae Hee Jung, Gwi-Nam Bae, Dong-Jin Lee
Aerosol Science and Technology.2010; 44(12): 1131. CrossRef

Production of Nano Powder by Using Transferred Thermal Plasma: Tae-Jin Jo, Heon-Chang Kim, Chang-Suk Han, Jwa-Yeon Kim, Young-Suk Kim; J Korean Powder Metall Inst. 2007;14(2):116-122.; DOI: https://doi.org/10.4150/KPMI.2007.14.2.116

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Abstract PDF: It is well known that thermal plasma process has lots of advantages such as high temperature and good quality for synthesis of nano particles. In this research, we attempt the synthesis of nano unitary and composite powder (Ag, Mg-Al, Zr-V-Fe) using transferred thermal plasma. Nano particles of metal alloy, ranging from 20 nm to 150 nm, have been synthesized by this process.

An Investigation of Dispersion Behavior of Y₂O₃ Ceramic Particles in Hypo, Eutectic and Hyper Binary Al-Cu Cast Alloys: J.J. Park, G.H. Kim, S.M. Hong, S.H. Lee, M.K. Lee, C.K. Rhee; J Korean Powder Metall Inst. 2007;14(2):123-126.; DOI: https://doi.org/10.4150/KPMI.2007.14.2.123

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Abstract PDF: In this work, the dispersion behavior of Y_2O_3 particles in binary aluminum (Al)-copper (Cu) cast alloy was investigated with respect to Cu contents of 20 (hypoeutertic), 33 (eutectic) and 40 (hypereutectic) wt.%. In cases of hypo and hypereutectic compositions, SEM images revealed that the primary Al and theta phases were grown up at the beginning, respectively, and thereafter the eutectic phase was solidified. In addition, it was found that some of Y_2O_3 particles can be dispersed into the primary Al phase, but none of them are is observed inside the primary 6 phase. This different dispersion behavior of Y_2O_3 particles is probably due to the difference in the val- ues of specific gravity between Y_2O_3 particles and primary phases. At eutectic composition, Y_2O_3 particles were well dispersed in the matrix since there is few primary phases acting as an impediment site for particle dispersion during solidification. Based on the experimental results, it is concluded that Y_2O_3 particles are mostly dispersed into the eutectic phase in binary Al-Cu alloy system.

Effect of Alumina Nanooxide Application on Nitrendipine Manufacturing Process: E.J. Chae, Y.R. Uhm, B.S. Han, C.K. Rhee, S.E. Park; J Korean Powder Metall Inst. 2007;14(2):127-131.; DOI: https://doi.org/10.4150/KPMI.2007.14.2.127

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Abstract PDF: The alumina nano powders synthesized by levitational gas condensation (LGC) method were applied to catalyst in manufacturing process of Hanzsch reaction for Nitrendipine. The L-tartaric acid on the surface is carried out with participation of carbonyl fragments, O-H, C-H bonds which affects stereo selectivity, yield on the reagents positively. From the analysis of the IR-spectroscopy, the carbonyl fragments, O-H, and C-H bond were created by the catalytic reaction. From the analysis of the rR-spectroscopy, the carbonyl fragments, O-H, and C-H bond were created by the catalytic reaction. The newly created bonds made a chiral center on the final product.

Microstructural Evolution and Properties in Ti(CN)-Co/Ni Cermet Depending on the Starting Material for Incorporation of WC: Tai-Joo Chung, Sun-Yong Ahn, Seung-Su Ahn, Myung-Soo Shin, Hak-Kyu Kim, Kyung-Bae Kim, Kyung-Sik Oh, Hyuk-Jae Lee; J Korean Powder Metall Inst. 2007;14(2):132-139.; DOI: https://doi.org/10.4150/KPMI.2007.14.2.132

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In the Ti(CN)-Co/Ni cermet, WC is an effective additive for increasing sinterability and mechanical properties such as toughness and hardness. In this work, WC, (WTi)C and (WTi)(CN) were used as the source of WC and their effects were investigated in the respect of microstructural evolution and mechanical properties. Regardless of the kinds of WC sources, the hard phase with dark core and bright rim structure was observed in the Ti(CN)-Co/Ni cermet under the incorporation of relatively small amount of WC. However, hard phases with bright core began to appear and their frequency increased with the increase of all kinds of WC source addition. The ratio of bright core to dark one in the (TiW)(CN)-Co/Ni cermet was greatest under the incorporation of (WTi)C compared at the same equivalent amount of WC. The mechanical properties were improved with the addition of WC irrespective of the kinds of sources, but the addition of (WTi)(CN) was less effective for the increase of fracture toughness.

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Investigation into the microstructure and cutting performance of (Ti,Ta,W)(CN)–Co/Ni cermets
Se-Woong Oh, Sun-Yong Ahn, Kyung-Sik Oh, Hyukjae Lee, Tai-Joo Chung
International Journal of Refractory Metals and Hard Materials.2015; 53: 36. CrossRef

Consolidation Behavior of Gas Atomized Mg-Zn-Y Alloy Powders by Spark Plasma Sintering: Jin-Kyu Lee, Taek-Soo Kim, Jung-Chan Bae; J Korean Powder Metall Inst. 2007;14(2):140-144.; DOI: https://doi.org/10.4150/KPMI.2007.14.2.140

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Using Spark Plasma Sintering process (SPS), consolidation behavior of gas atomized Mg_97Zn_1Y_2 alloys were investigated via examining the microstructure and evaluating the mechanical properties. In the atomized ahoy powders, fine Mg_12YZn particles were homogeneously distributed in the alpha-Mg matrix. The phase distribution was maintained even after SPS at 723 K, although Mg_24Y_5 particles were newly precipitated by consolidating at 748 K. The density of the consolidated bulk Mg-Zn-Y alloy was 1.86g/cm3. The ultimate tensile strength (UTS) and elongation were varied with the consolidation temperature.

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High Temperature Deformation Flow Of A ZK60A Magnesium Alloy After Extrusion
M. Kawasaki, H.-J. Lee, M.C. Oh, B. Ahn
Archives of Metallurgy and Materials.2015; 60(2): 1327. CrossRef

Nano Particle Coatings on α-alumina Powders by a Carbonate Precipitation: Jong-Min Lim, Sang-Woo Kim; J Korean Powder Metall Inst. 2007;14(2):145-149.; DOI: https://doi.org/10.4150/KPMI.2007.14.2.145

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Abstract PDF: Nanocrystalline transient aluminas (gamma-alumina) were coated on core particles (gamma-alumina) by a carbonate precipitation and thermal-assisted combustion, which is environmentally friend. The ammonium aluminum carbonate hydroxide (AACH) as a precursor for coating of transient aluminas was produced from precipitation reaction of ammonium aluminum sulfate and ammonium hydrogen carbonate. The crystalline size and morphology of the synthetic, AACH, were greatly dependent on pH and temperature. AACH with a size of 5 nm was coated on the core alumina particle at pH 9. whereas rod shape and large agglomerates were coated at pH 8 and 11, respectively. The AACH was tightly bonded coated on the core particle due to formation of surface complexes by the adsorption of carbonates, hydroxyl and ammonia groups on the surface of the core alumina powder. The synthetic precursor successfully converted to amorphous- and gamma-alumina phase at low temperature through decomposition of surface complexes and thermal-assisted phase transformation.

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