Journal of Powder Materials

Dong-Won Lee

14 Articles

Study on the Reduction of Forging Oxide Scale using Hydrogen: Dong-Won Lee, Jung-Yeul Yun, Shun-Myung Shin, In-Soo Kim, Jei-Pil Wang; J Korean Powder Metall Inst. 2013;20(3):174-179.; DOI: https://doi.org/10.4150/KPMI.2013.20.3.174

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The study on the fabrication of iron powder from forging scales using hydrogen gas has been conducted on the effect of hydrogen partial pressure, temperature, and reactive time. The mechanism for the reduction of iron oxides was proposed with various steps, and it was found that reduction pattern might be different depending on temperature. The iron content in the scale and reduction ratio of oxygen were both increased with increasing reactive time at 0.1atm of hydrogen partial pressure. On the other hand, for over 30 minutes at 0.5 atm of hydrogen partial pressure, the values were found to be almost same. In the long run, iron metallic powder was obtained with over 90% of iron content and an average size of its powder was observed to be about 100µm.

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Effects of expanded graphite content on the performance of MgO‐C refractories
Junseong Kim, Seunghwa Jeong, Minsuk Lee, Dong Jae Kang, Hong‐woo Park, Hwa‐In Lee, Dong‐Yeol Yang, Eun Hee Kim, Soonil Lee, Seung‐Cheol Yang, Sang‐Chae Jeon
International Journal of Applied Ceramic Technology.2023; 20(6): 3803. CrossRef
Smithing Processes Based on Hammer Scale Excavated from the Third- to Fourth-Century Ancient Iron-Making Sites of the Korean Peninsula
Dayeon Jung, Heehong Kwon, Namchul Cho
Materials.2022; 15(12): 4188. CrossRef

Trend in Research and Development of Recovery of Valuable Metallic Powder from Wasted Batteries: Shun-Myung Shin, Sung-Ho Joo, Dong-Won Lee, Jung-Yeul Yun, Jei-Pil Wang; J Korean Powder Metall Inst. 2013;20(1):60-67.; DOI: https://doi.org/10.4150/KPMI.2013.20.1.060

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A study on Zn recovery from other metals in the spent mixed batteries through a sequence of hydrometallurgical processes
Dong Ju Shin, Sung-Ho Joo, Chang-Hyun Oh, Jei-Pil Wang, Jin-Tae Park, Dong Joon Min, Shun Myung Shin
Environmental Technology.2019; 40(26): 3512. CrossRef
Development of Batch-Type Electric Furnace for Recovery of Valuable Materials from Spent Batteries
Shun Myung Shin, Dong Won Lee, Jung Yeul Yun, Byung Ho Jung, Jei Pil Wang
Applied Mechanics and Materials.2014; 607: 197. CrossRef

Oxidation Study on the Fabrication of Fe-36Ni Oxide Powder from Its Scrap: Jung Yeul Yun, Man Ho Park, Sangsun Yang, Dong-Won Lee, Jei-Pil Wang; J Korean Powder Metall Inst. 2013;20(1):48-52.; DOI: https://doi.org/10.4150/KPMI.2013.20.1.048

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Abstract PDF: A study of oxidation kinetic of Fe-36Ni alloy has been investigated using thermogravimetric apparatus (TGA) in an attempt to define the basic mechanism over a range of temperature of 400 to 1000°C and finally to fabricate its powder. The oxidation rate was increased with increasing temperature and oxidation behavior of the alloy followed a parabolic rate law at elevated temperature. Temperature dependence of the reaction rate was determined with Arrhenius-type equation and activation energy was calculated to be 106.49 kJ/mol. Based on the kinetic data and micro-structure examination, oxidation mechanism was revealed that iron ions and electrons might migrate outward along grain boundaries and oxygen anion diffused inward through a spinel structure, (Ni,Fe)_3O_4.

Extraction of Vanadium Powder by Metallothermic Reduction: Dong-Won Lee, Sang-Hyun Heo, Jong-Taek Yeom, Jei-Pil Wang; J Korean Powder Metall Inst. 2013;20(1):43-47.; DOI: https://doi.org/10.4150/KPMI.2013.20.1.043

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The extraction of metallic pure vanadium powder from raw oxide has been tried by Mg-reduction. In first stage, V_2O_5 powders as initial raw material was reduced by hydrogen gas into V_2O_3 phase. V_2O_3 powder was reduced in next stage by magnesium gas at 1,073K for 24 hours. After reduction reaction, the MgO component mixed with reduced vanadium powder were dissolved and removed fully in 10% HCl solution for 5 hours at room temperature. The oxygen content and particle size of finally produced vanadium powders were 0.84 wt% and 1 µm, respectively

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Preparation of tantalum metal powder by magnesium gas reduction of tantalum pentoxide with different initial particle size
Seon-Min Hwang, Su-Jin Park, Jei-Pil Wang, Yong-Ho Park, Dong-Won Lee
International Journal of Refractory Metals and Hard Materials.2021; 100: 105620. CrossRef
Metallic Niobium Powder Reduced by Atmospheric Magnesium Gas with Niobium Pentoxide Powder
Su-Jin Park, Seon-Min Hwang, Jei-pil Wang, Young-Guk Son, Dong-Won Lee
MATERIALS TRANSACTIONS.2021; 62(1): 34. CrossRef
Fabrication of Metallic Tantalum Powder by Magnesium-gas Reduction of Tantalum Oxide
Dong-Won Lee
Journal of Korean Powder Metallurgy Institute.2018; 25(5): 390. CrossRef
Effect of magnesium on the phase equilibria in magnesio-thermic reduction of Nb2O5
Kyunsuk Choi, Hanshin Choi, Hyunwoong Na, Il Sohn
Materials Letters.2016; 183: 151. CrossRef

Synthesis of Ultrafine and Less Agglomerated TiCN Powders by Magnesiothermic Reduction: Dong-Won Lee; J Korean Powder Metall Inst. 2012;19(5):356-361.; DOI: https://doi.org/10.4150/KPMI.2012.19.5.356

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Abstract PDF: The ultra-fine and less agglomerated titanium carbonitride particles were successfully synthesized by magnesiothermic reduction with low feeding rate of TiCl_4+1/4C_2Cl_4 solution. The sub-stoichiometric titanium carbide (TiC_0.5sim0.6) particles were produced by reduction of chlorine component by liquid magnesium at 800°C of gaseous TiCl_4+1/4C_2Cl_4 and the heat treatments in vacuum were performed for 5 hours to remove the residual magnesium and magnesium chloride mixed with produced TiC_sim0.5. The final TiC_sim0.5N_0sim0.5 particle with near 100 nm in mean size and high specific surface area of 65m2/g was obtained by nitrification under nitrogen gas at 1,150°C for 2 hrs.

Fabrication of Ultrafine Tungsten-based Composite Powders by Novel Reduction Process: Dong-Won Lee; J Korean Powder Metall Inst. 2012;19(5):338-342.; DOI: https://doi.org/10.4150/KPMI.2012.19.5.338

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Abstract PDF: A novel chemical method was evaluated to fabricate the ultrafine tungsten heavy alloy powders with bater-base solution made from the ammonium metatungstate (AMT), iron(II) chloride tetrahydrate (FeCl_2cdot4H_2O), nickel(II) chloride hexahydrate (NiCl_2cdot6H_2O) as source materials and the sodium tungstate dihydrate (NaWO_4cdot2H_2O) as Cl-reductant. In the preparation of mixtures the amounts of the source components were chosen so as to obtain alloy of 93W-5Ni-2Fe composition(wt.%). The obtained powders were characterized by X-ray diffraction, XRF, field-emission scanning microscope (FESEM), and chemical composition was analyzed by EDX.

Synthesis of Zr-Ti Alloy Powder by Magnesium Reduction: Dong-Won Lee, Geun-Tae Park, Tae-Soo Lim, Hye-Moon Lee, Ji-Hun Yu; J Korean Powder Metall Inst. 2011;18(4):359-364.; DOI: https://doi.org/10.4150/KPMI.2011.18.4.359

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Zr-Ti alloy powders were successfully synthesized by magnesium thermal reduction of metal chlorides. The evaporated and mixed gasses of ZrCl_4+TiCl_4 were injected to liquid magnesium and the chloride components were reduced by magnesium leading to the formation of MgCl_2. The released Zr and Ti atoms were then condensed to particle forms inside the mixture of liquid magnesium and magnesium chloride, which could be dissolved fully in post process by 1~5% HCl solution at room temperature. By the fraction-control of individually injected ZrCl_4 and TiCl_4 gasses, the final compositions of produced alloy powders were changed in the ranges of Zr-0 wt.%~20 wt.%Ti and their purity and particle size were about 99.4% and the level of several micrometers, respectively.

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Synthesis of Vanadium Powder by Magnesiothermic Reduction
Dong Won Lee, Hak Sung Lee, Jung Yeul Yun, Young Ho Kim, Jei Pil Wang
Advanced Materials Research.2014; 1025-1026: 509. CrossRef
Extraction of Vanadium Powder by Metallothermic Reduction
Dong-Won Lee, Sang-Hyun Heo, Jong-Taek Yeom, Jei-Pil Wang
Journal of Korean Powder Metallurgy Institute.2013; 20(1): 43. CrossRef

Oxygen-Response Ability of Hydrogen-Reduced Nanocrystalline Cerium Oxide: Dong-Won Lee; J Korean Powder Metall Inst. 2011;18(3):250-255.; DOI: https://doi.org/10.4150/KPMI.2011.18.3.250

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Abstract PDF: The potential application of ultrafine cerium oxide (ceria, CeO_2) as an oxygen gas sensor has been investigated. Ceria was synthesized by a thermochemical process: first, a precursor powder was prepared by spray drying cerium-nitrate solution. Heat treatment in air was then performed to evaporate the volatile components in the precursor, thereby forming nanostructured CeO_2 having a size of approximately 20 nm and specific surface area of 100 m2/g. After sintering with loosely compacted samples, hydrogen-reduction heat treatment was performed at 773K to increase the degree of non-stoichiometry, x, in CeO_2-x. In this manner, the electrical conductivity and oxygen-response ability could be enhanced by increasing the number of oxygen vacancies. After the hydrogen reduction at 773K, CeO_1.5 was obtained with nearly the same initial crystalline size and surface. The response time t_90 measured at room temperature was extremely short at 4 s as compared to 14 s for normally sintered CeO_2. We believe that this hydrogen-reduced ceria can perform capably as a high-performance oxygen sensor with good response abilities even at room temperature.

Characteristics of Stainless Steel Composites with Nano-sized TiCxNy: Tae-Ho Ban, Sung-Bum Park, Soo-Jeong Jo, Dong-Won Lee, Farkhod R. Turaev, Yong-Il Park, Sung-Jin Kim; J Korean Powder Metall Inst. 2011;18(3):290-296.; DOI: https://doi.org/10.4150/KPMI.2011.18.3.290

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Abstract PDF: Titanium carbonitride is more perspective materials compared to titanium carbide. It can be used in tool industry and special products because of its higher strength, abrasive wear-resistance and especially its strong chemical stability at high temperatures. We produced STS+TiCxNy composite by the spark plasma sintering for higher strength and studied the characteristics. The planar and cross-sectional microstructures of the specimens were observed by scanning electron microscopy. Characterizations of the carbon and nitride phases on the surface of composite were carried out using an X-ray diffractometer. During annealing TiCxNy particles diffusion into STS 430 was observed. After annealing, sintering isolations between particles were formed. It causes decreasing of mechanical strength. In addition when annealing temperature was increased hardness increased. Heterogeneous distribution of alloying elements particles was observed. After annealing composites, highest value of hardness was 738.1 MHV.

Hydrogenation Behavior of Sponge Titanium: Ji-Hwan Park, Dong-Won Lee, Jong-Ryoul Kim; J Korean Powder Metall Inst. 2010;17(5):385-389.; DOI: https://doi.org/10.4150/KPMI.2010.17.5.385

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Titanium powders have been usually produced by de-hydrogenating treatment in vacuum with titanium hydride (TiH_2) powders prepared by milling of hydrogenated sponge titanium, TiH_x. The higher stoichiometry of x in TiH_x, whose maximum value is 2, is achieved, crushing behavior is easier. TiH_x powder can be, therefore, easy to manufactured leading to obtain higher recovery factor of it. In addition, contamination of the powder can also minimized by the decrease of milling time. In this study, the hydrogenation behavior of sponge titanium was studied to find the maximum stoichiometry. The maximum stoichiometry in hydride formation of sponge titanium could be obtained at 750°C for 2 hrs leading to the formation of TiH_sim1.99 and the treating temperatures lower or higher than 750°C caused the poor stoichiometries by the low hydrogen diffusivity and un-stability of TiH_x, respectively. Such experimental behavior was compared with thermodynamically calculated one. The hydrogenated TiH_1.99 sponge was fully ball-milled under -325 Mesh and the purity of pure titanium powders obtained by de-hydrogenation was about 99.6%.

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Effect of Ball Milling Conditions on the Microstructure and Dehydrogenation Behavior of TiH2 Powder
Ji Young Kim, Eui Seon Lee, Ji Won Choi, Youngmin Kim, Sung-Tag Oh
journal of Korean Powder Metallurgy Institute.2024; 31(2): 132. CrossRef
Study on Manufacture of High Purity TiCl₄ and Synthesis of High Purity Ti Powders
Jieun Lee, Jin-Ho Yoon, Chan Gi Lee
Journal of Korean Powder Metallurgy Institute.2019; 26(4): 282. CrossRef
Effect of Heat Treatment Temperature and Atmosphere on the Microstructure of TiH2-WO3 Powder Mixtures
Han-Eol Lee, Yeon Su Kim, Sung-Tag Oh
Journal of Korean Powder Metallurgy Institute.2017; 24(1): 41. CrossRef
Titanizing on the surface of iron metal foam
Su-In Lee, Jung-Yeul Yun, Tae-Soo Lim, Byoung-Kee Kim, Young-Min Kong, Jei-Pil Wang, Dong-Won Lee
Thermochimica Acta.2014; 581: 87. CrossRef
Study on synthesis of Zr–Ti alloy powder using molten magnesium
D.-W. Lee, Y.-K. Baek, W.-J. Lee, J.-P. Wang
Materials Research Innovations.2013; 17(sup2): s113. CrossRef
Direct synthesis of zirconium powder by magnesium reduction
Dong-Won Lee, Jung-Yeul Yun, Sung-Won Yoon, Jei-Pil Wang
Metals and Materials International.2013; 19(3): 527. CrossRef
Synthesis of Zr-Ti Alloy Powder by Magnesium Reduction
Dong-Won Lee, Geun-Tae Park, Tae-Soo Lim, Hye-Moon Lee, Ji-Hun Yu
Journal of Korean Powder Metallurgy Institute.2011; 18(4): 359. CrossRef

Preparation of Ultrafine C/N Controled TiC_xN_y Powders by Magnesium Reduction: Dong-Won Lee, Byoung-Kee Kim, Jung-Yeul Yun, Ji-Hoon Yu, Yong-Jin Kim; J Korean Powder Metall Inst. 2010;17(2):142-147.; DOI: https://doi.org/10.4150/KPMI.2010.17.2.142

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The ultrafine titanium carbonitride (TiC_xN_y) particles below 100 nm in mean size, including various carbon and nitrogen contents (x=0.55~0.9, y=0.1~0.5), were successfully synthesized by new Mg-thermal reduction process. Nanostructured sub-stoichiometric titanium carbide (TiC_x) particles were initially produced by the magnesium reduction of gaseous TiCl_4+x/2C_2Cl_4 at 890°C and post heat treatments in vacuum were performed for 2 hrs to remove residual magnesium and magnesium chloride mixed with TiC_x. Finally, well C/N-controled TiC_xN_y phases were successfully produced by nitrification heat treatment under normal N_2 gas atmosphere at 1150°C for 2 hrs. The values of purity, mean particle size and oxygen content of produced particles were about 99.3%, 100 nm and 0.2 wt.%, respectively.

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Characteristics of Stainless Steel Composites with Nano-sized TiCxNy
Tae-Ho Ban, Sung-Bum Park, Soo-Jeong Jo, Dong-Won Lee, Farkhod R. Turaev, Yong-Il Park, Sung-Jin Kim
Journal of Korean Powder Metallurgy Institute.2011; 18(3): 290. CrossRef

Preparation of Ultrafine TiCN Powders by Mg-reduction of Metallic Chlorides: Dong-Won Lee, Jin-Chun Kim, Yong-Jin Kim, Byoung-Kee Kim; J Korean Powder Metall Inst. 2009;16(2):98-103.; DOI: https://doi.org/10.4150/KPMI.2009.16.2.098

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The ultrafine titanium carbonitride particles (TiC_0.7N_0.3) below 100nm in mean size were successfully synthesized by Mg-thermal reduction process. The nanostructured sub-stoichiometric titanium carbide (TiC_0.7) particles were produced by the magnesium reduction at 1123K of gaseous TiC_l4+xC_2Cl_4 and the heat treatments in vacuum were performed for five hours to remove residual magnesium and magnesium chloride mixed with TiC_0.7. And final TiC_0.7N_0.3 phase was obtained by nitrification under normal N_2 gas at 1373K for 2 hrs. The purity of produced TiC_0.7N_0.3 particles was above 99.3% and the oxygen contents below 0.2 wt%. We investigated in particular the effects of the temperatures in vacuum treatment on the particle refinement of final product.

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Synthesis of Ultrafine and Less Agglomerated TiCN Powders by Magnesiothermic Reduction
Dong-Won Lee
Journal of Korean Powder Metallurgy Institute.2012; 19(5): 356. CrossRef
Preparation of Ultrafine C/N Controled TiCxNyPowders by Magnesium Reduction
Dong-Won Lee, Byoung-Kee Kim, Jung-Yeul Yun, Ji-Hoon Yu, Yong-Jin Kim
Journal of Korean Powder Metallurgy Institute.2010; 17(2): 142. CrossRef

Synthesis and Characterization of WS₂ Nanoparticles by Chemical Vapor Condensation: Dong-Won Lee, Ju-Hyeong Kim, O. Tolochko, Jung-Yeul Yun, Byung-Kee Kim; J Korean Powder Metall Inst. 2008;15(4):314-319.; DOI: https://doi.org/10.4150/KPMI.2008.15.4.314

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Abstract PDF: Nano-sized tungsten disulfide (WS_2) powders were synthesized by chemical vapor condensation (CVC) process using tungsten carbonyl (W(CO)_6) as precursor and vaporized pure sulfur. Prior to the synthesis of tungsten disulfide nanoparticles, the pure tungsten nanoparticles were produced by same route to define the optimum synthesis parameters, which were then successfully applied to synthesize tungsten disulfide. The influence of experimental parameters on the phase and chemical composition as well as mean size of the particles for the produced pure tungsten and tungsten disulfide nanoparticles, were investigated.

Characteristics of L1₀ Ordered Fe₅₀Pt₅₀ Nanoparticles Synthesized by Chemical Vapor Condensation Process: Gyeong-Mo Lee, Ji-Hun Yu, Dong-Won Lee, Byung-Kee Kim, Hyeok-Don Kim, Tae-Suk Jang; J Korean Powder Metall Inst. 2007;14(5):281-286.; DOI: https://doi.org/10.4150/KPMI.2007.14.5.281

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Abstract PDF: Ordered L1_0 to FePt nanoparticles are strong candidates for high density magnetic data storage media because the L1_0 phase FePt has a very high magnetocrystalline anisotropy (K_usim6.6-10times107erg/cm3), high coercivity and chemical stability. In this study, the ordered L1_0 FePt nanoparticles were successfully fabricated by chemical vapor condensation process without a post-annealing process which causes severe particle growth and agglomeration. The Fe_50Pt_50 nanopowder was obtained when the mixing ratio of Fe(acac) and Pt(arac) was 2.5 : 1. And the synthesized FePt nanoparticles were very fine and spherical shape with a narrow size distribution. The average particle size of the powder tended to increase from 5 nm to 10 nm with increasing reaction temperature from 800°C to 1000°C. Characterisitcs of FePt nanopowder were investigated in terms of process parameters and microstructures.

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