Journal of Powder Materials

Development and Application of Metal Nanoparticles for Printed Electronics: Application to Metal Ink in Ink-Jet Technology: Kun-Jae Lee, Yong-Ho Choa; J Korean Powder Metall Inst. 2008;15(2):81-86.; DOI: https://doi.org/10.4150/KPMI.2008.15.2.081

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Fabrication of Nitride Fuel Pellets by Using Simulated Spent Nuclear Fuel: Ho-Jin Ryu, Jae-Won Lee, Young-Woo Lee, Jung-Won Lee, Geun-Il Park; J Korean Powder Metall Inst. 2008;15(2):87-94.; DOI: https://doi.org/10.4150/KPMI.2008.15.2.087

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In order to investigate a nitriding process of spent oxide fuel and the subsequent change in thermal properties after nitriding, simulated spent fuel powder was converted into a nitride pellet with simulated fission product elements through a carbothermic reduction process. Nitriding rate of simulated spent fuel was decreased with increasing of the amount of fission products. Contents of Ba and Sr in simulated spent fuel were decreased after the carbothermic reduction process. The thermal conductivity of the nitride pellet was decreased by an addition of fission product element but was higher than that of the oxide fuel containing fission product elements.

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Dissolution Behavior of Simulated Spent Nuclear Fuel in LiCl-KCl-UCl3 Molten Salt
Sang-Kwon Lee, Sung-Wook Kim, Jun-Hyuk Jang, Min Ku Jeon, Eun-Young Choi, Guglielmo Lomonaco
Science and Technology of Nuclear Installations.2021; 2021: 1. CrossRef
Nitration by a simulated fuel technique for nitride fuel re-fabrication
Young.-Woo Lee, Ho Jin Ryu, Jae Won Lee, Jung Won Lee, Geun Il Park
Journal of Nuclear Materials.2009; 392(2): 171. CrossRef

Surface Treatment of Mg₉₅Zn_4.3Y_0.7 Alloy Powder Consolidates using Plasma Electrolytic Oxidation: J.H. Kim, H.S. Choi, D.H. Kim, D.Y. Hwang, H.S. Kim, T.S. Kim; J Korean Powder Metall Inst. 2008;15(2):95-100.; DOI: https://doi.org/10.4150/KPMI.2008.15.2.095

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Abstract PDF: The investigation is to modify the mechanical and chemical properties of Mg alloys using a combination of rapid solidification and surface treatment. As the first approach, Mg_95Zn_4.3Y_0.7 was gas atomized and pressure sintered by spark plasma sintering process (SPS), showing much finer microstructure and higher strength than the alloys as cast. Further modification was performed by treating the surface of PM Mg specimen using Plasma electrolytic oxidation (PEO) process. During the PEO processing, MgO layer was initiated to form on the surface of Mg powder compacts, and the thickness and the density of MgO layer were varied with the reaction time. The thickening rate became low with the reaction time due to the limited diffusion rate of Mg ions. The surface morphology, corrosion behavior and wear resistance were also discussed.

Characteristics of the Surface Coating Layer of Ti₅Si₃ Intermetallic Compound Obtained by Shock Compaction and Reaction Synthesis Through Underwater Shock Compression: Sang-Hoon Lee; J Korean Powder Metall Inst. 2008;15(2):101-106.; DOI: https://doi.org/10.4150/KPMI.2008.15.2.101

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Abstract PDF: The objective of the present study is to investigate the increase in the functional characteristics of a substrate by the formation of a thin coating layer. Thin coating layers of Ti_5Si_3 have high potential because Ti_5Si_3 exhibits high hardness. Shock induced reaction synthesis is an attractive fabrication technique to synthesize uniform coating layer by controlling the shock wave. Ti and Si powders to form Ti_5Si_3 using shock induced reaction synthesis, were mixed using high-energy ball mill into small scale. The positive effect of this technique is highly functional coating layer on the substrate due to ultra fine substructure, which improves the bonding strength. These materials are in great demand as heat resisting, structural and corrosion resistant materials. Thin Ti_5Si_3 coating layer was successfully recovered and showed high Vickers' hardness (Hv=1183). Characterization studies on microstructure revealed a fairly uniform distribution of powders with good interfacial integrity between the powders and the substrate.

Synthesis of Ultrafine TiC-5%Co Powder by Using Co Nitrate and TiO(OH)₂ Slurry and Evaluation of Sintered Materials Prepared by Mixing WC-Co: Seong-Hyeon Hong, Byoung-Kee Kim; J Korean Powder Metall Inst. 2008;15(2):107-113.; DOI: https://doi.org/10.4150/KPMI.2008.15.2.107

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Abstract PDF: Ultrafine TiC-5%Co powders were synthesized by spray drying of aqueous solution of TiO(OH)_2 slurry and cobalt nitrate, followed by calcination and carbothermal reaction. The oxide powders with carbon powder was reduced and carburized at 900°Csim1250°C under hydrogen atmosphere. During reduction, CO gas was mainly evolved by reducing reaction of oxides. Ultrafine TiC-5%Co powders were easily formed by carbothermal reaction at 1250°C due to using ultrafine powders as raw materials. The ultrafine WC-TiC-Co alloy prepared by sintering of mixed powder of ultrafine WC-13%Co powder and ultrafine TiC-5%Co powder has higher sintered density and mechanical properties than WC-TiC-Co alloy prepared by commercial WC, TiC and Co powders.

Fabrication and Characterization of Ag Nanoparticle Dispersed Polymer Nanofiber and Ag Nanofiber Using Electrospinning Method: Hee-Taik Kim, Chi-Yong Hwang, Han-Bok Song, Kun-Jae Lee, Yeon-Jun Joo, Seong-Jei Hong, Nam-Kee Kang, Seong-Dae Park, Ki-Do Kim, Yong-Ho Cho; J Korean Powder Metall Inst. 2008;15(2):114-118.; DOI: https://doi.org/10.4150/KPMI.2008.15.2.114

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Functional nanomaterial is expected to have improved capacities on various fields. Especially, metal nanoparticles dispersed in polymer matrix and metal nanofiber, one of the functional nanomaterials, are able to achieve improvement of property in the electric and other related fields. In this study, the fabrication of metal (Ag) nanoparticle dispersed nanofibers were attempted. The Ag nanoparticle dispersed polymer nanofiber and Ag nanofiber were fabricated by electrospinning method using electric force. First, PVP/AgNO_3 nanofibers were synthesized by electrospinning in 18sim22kV voltage with the starting materials (Ag-nitrate) added polymer (PVP; poly (vinylpyrrolidone)). Then Ag nanoparticle dispersed polymer nanofibers were fabricated to reduce hydrogen reduction at 150°C for 3hr. And Ag nanofibers were synthesized by the decomposited of PVP at 300sim500°C for 3hr. The nanofibers were analyzed by XRD, TGA, FE-SEM and TEM. The experimental results showed that the Ag nanofibers could be applied in many fields as an advanced material.

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Fabrication of Nanowire by Electrospinning Process Using Nickel Oxide Particle Recovered from MLCC
Haein Shin, Jongwon Bae, Minsu Kang, Kun-Jae Lee
journal of Korean Powder Metallurgy Institute.2023; 30(6): 502. CrossRef
Fabrication of Flake-like LiCoO2Nanopowders using Electrospinning
Bon-Ryul Koo, Geon-Hyoung An, Hyo-Jin Ahn
Journal of Korean Powder Metallurgy Institute.2014; 21(2): 108. CrossRef
Synthesis of Fe-Doped TiO2/α-Fe2O3 Core-Shell Nanowires Using Co-Electrospinning and Their Magnetic Property
본율 구, 효진 안
Korean Journal of Materials Research.2014; 24(8): 423~428. CrossRef

Improvement of Pot Life in the Epoxy Resin-based Adhesive Formulation by Size Control and Coating of Curing Accelerator Powders: Jun-Sik Lee, Chang-Yong Hyun, Jong-Hyun Lee; J Korean Powder Metall Inst. 2008;15(2):119-124.; DOI: https://doi.org/10.4150/KPMI.2008.15.2.119

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Abstract PDF: To increase pot life in the formulation mixed with bisphenol F epoxy resin, anhydride-based curing agent, and imidazole-based curing accelerator powders as a paste material for high-speed RFID chip bonding, size variation of the imidazole-based powders and a coating method of the powders were adopted in this study. In experiment with regard to the size variation, the pot life was not outstandingly increased. Through the idea using the coating method, however, the pot life was increased up to 4.25 times in comparison with the addition of initial imidazole-based powders. Consequently, successive bonding of RFID chip could be performed with very short time of 5sec using the suggested formulation having improved pot life.

Titanate Nanotube Formation and Nanostructure Development from the Reaction of TiO₂ Nanopowder and Alkalihydroxide: Eun-Ju Jin, Doh-Hyung Riu, Seung-Hun Huh, Chang-Yeoul Kim, Hae-Jin Hwang; J Korean Powder Metall Inst. 2008;15(2):125-135.; DOI: https://doi.org/10.4150/KPMI.2008.15.2.125

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[ TiO_2 ] nanotubes for photocatalytic application have been synthesized by hydrothermal method. TiO_2 nanotubes are formed by washing process after reaction in alkalic solution. Nanotubes with different morphology have been fabricated by changing NaOH concentration, temperature and time. TiO_2 nanoparticles were treated inside NaOH aqueous solution in a Teflon vessel at 110°C for 20 h, after which they were washed with HCl aqueous solution and deionized water. Nanotube with the most perfect morphology was formed from 0.1 N HCl washing treatment. TiO_2 nanotube was also obtained when the precursor was washed with other washing solutions such as NH_4OH, NaCl, K_2SO_4, and Na_2SO_3. Therefore, it was suggested that Na+ ion combined inside the precursor compound slowly comes out from the structure, leaving nanosheet morphology of TiO_2 compounds, which in turn become the nanotube in the presence of hydroxyl ion. To stabilize the sheet morphology, the different type of washing treatment solution might be considered such as amine class compounds.

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Coating Property of Hybrid Structured Photo-Electrode to Increase Dye-Sensitized Solar Cells Efficiency
Min-Hee Kim, Hyung-Woo Lee, Young-Keun Jeong
Journal of Korean Powder Metallurgy Institute.2010; 17(6): 449. CrossRef

Synthesis of Eu³⁺ Doped (Y,Gd)BO₃ Powder by Mechanochemical Process: Hee-Sub Won, Wan-Jae Lee, Je-Seok Kim, Gun-Young Hong, Kun-Jae Lee, Yong-Ho Choa; J Korean Powder Metall Inst. 2008;15(2):136-141.; DOI: https://doi.org/10.4150/KPMI.2008.15.2.136

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The mechanochemical process were employed to prepare the red phosphors (Y,Gd)BO_3:Eu3+. The main factors affecting particle size, particle distribution, and luminescent properties of the product were investigated in details. Particles sized around 200-600 nm are formed after intensive milling. The phosphors were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and photoluminescence spectrum. Results revealed that phosphors with different morphology, small particle size and high luminescence intensity could be obtained by mechanochemical process.

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Photoluminescence Properties of Green Phosphor Y1-xBO3:Tbx3+Synthesized by Solid-state Reaction Method
Shin-Ho Cho
Journal of the Korean Institute of Electrical and Electronic Material Engineers.2011; 24(8): 659. CrossRef

Fabrication and Properties of High Strength Hypereutectic AI-Si Powders by a Gas Atomization Process II. Extrusion and Mechanical Properties: Yong-Jin Kim, Jin-Chun Kim; J Korean Powder Metall Inst. 2008;15(2):142-147.; DOI: https://doi.org/10.4150/KPMI.2008.15.2.142

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Abstract PDF: The hypereutectic Al-20 wt%Si powders including some amount of Cu, Fe, Mg, Mn were prepared by a gas atomization process. In order to get highly densified Al-Si bulk specimens, the as-atomized and sieved powders were extruded at 500°C, Microstructure and tensile properties of the extruded Al-Si alloys were investigated in this study. Relative density of the extruded samples was over 98%. Ultimate tensile strength (UTS) in stress-strain curves of the extruded powders increased after T6 heat treatments. Elongation of the samples was also increased from 1.4% to 3.2%. The fracture surfaces of the tested pieces showed a fine microstructure and the average grain size was about 1µm.

Preparation of Magnetite Nanoparticles by Two Step Reaction: Dae-Kyu Shin, Doh-Hyung Riu; J Korean Powder Metall Inst. 2008;15(2):148-155.; DOI: https://doi.org/10.4150/KPMI.2008.15.2.148

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Abstract PDF: Nano magnetite particles have been prepared by two step reaction consisting of urea hydrolysis and ammonia addition at certain ranges of pH. Three different concentrations of aqueous solution of ferric (Fe3+) and ferrous (Fe2+) chloride (0.3 M-0.6 M, and 0.9 M) were mixed with 4 M urea solution and heated to induce the urea hydrolysis. Upon reaching at a certain pre-determined pH (around 4.7), 1 M ammonia solution were poured into the heated reaction vessels. In order to understand the relationship between the concentration of the starting solution and the final size of magnetite, in-situ pH measurements and quenching experiments were simultaneous conducted. The changes in the concentration of starting solution resulted in the difference of the threshold time for pH uprise, from I hour to 3 hours, during which the akaganeite (beta-FeOOH) particles nucleated and grew. Through the quenching experiment, it was confirmed that controlling the size of beta-FeOOH and the attaining a proper driving force for the reaction of beta-FeOOH and Fe2+ ion to give Fe_3O_4 are important process variables for the synthesis of uniform magnetite nanoparticles.

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