Journal of Powder Materials

S.J. Hong

4 Articles

Microstructure and Characteristics of Ag-SnO₂ Contact Materials Prepared by Magnetic Pulsed Compaction: J.S. Park, Y.J. Kim, M.H. Lee, H.S. Lee, S.J. Hong, J.K. Lee; J Korean Powder Metall Inst. 2011;18(4):372-377.; DOI: https://doi.org/10.4150/KPMI.2011.18.4.372

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Abstract PDF: In this study, we reported the microstructure and properties of Ag-SnO_2 contact materials fabricated by a controlled milling process with subsequent consolidation. The milled powders were consolidated to bulk samples using a magnetic pulsed compaction process. The nano-scale SnO_2 phases were distributed homogeneously in the Ag matrix after the consolidation. The relative density and hardness of the Ag-SnO_2 contact materials were 95~96% and 89~131 Hv, respectively.

Consolidation of p-type Fe(Mn)Si₂ Thermoelectric Powder and Microstructure: J.S. Shim, S.J. Hong, B.S. Chun; J Korean Powder Metall Inst. 2008;15(5):345-351.; DOI: https://doi.org/10.4150/KPMI.2008.15.5.345

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Abstract PDF: The effects of the dopant (Mn) ratio on the microstructure and thermoelectric properties of FeSi_2 alloy were studied in this research. The alloy was fabricated by a combination process of ball milling and high pressure pressing. Structural behavior of the sintered bulks were systematically investigated by XRD, SEM, and optical microscopy. With increasing dopan (Mn) ratio, the density and varepsilon-FeSi phase of the sintered bulks increased and maximum density of 94% was obtained in the 0.07% Mn-doped alloy. The sintered bulks showed fine microstructure of alpha-Fe_2Si_5, varepsilon-FeSi and beta-FeSi_2 phase. The semiconducting phase of beta-FeSi_2 was transformed from alpha-Fe_2Si_5+varepsilon-FeSi phase by annealing.

Consolidation of Segment Powder for Diamond Tool by Magnetic Pulsed Compaction: J.S. Yun, J.G. Lee, M.K. Lee, C.K. Rhee, M.S. Park, S.J. Hong; J Korean Powder Metall Inst. 2008;15(5):378-385.; DOI: https://doi.org/10.4150/KPMI.2008.15.5.378

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This article presents the successful consolidation of the mixed Co and Diamond powders for a drilling segment by the combined application of magnetic pulsed compaction (MPC) and subsequent sintering, and their properties were analyzed. Homogeneous hardness (Hv 220) and density (97%) of sintered bulks fabricated by MPC were obtained by the new technique, where higher pressure has been employed for short period of time than that of general process. A fine microstructure and homogeneous hardness in the consolidated bulk were observed without cracks. Relatively higher drilling speed of 9.61 cm/min and life time of 6.55 m were found to the MPCed specimens, whereas the value of the specimens fabricated by general process was 11.71 cm/min and 7.96 m, respectively. A substantial improvement of mechanical properties of segment was achieved through this study.

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Machining Characteristics of Micro Structure using Single-Crystal Diamond Tool on Cu-plated Mold
Chang-Eui Kim, Eun-chae Jeon, Tae-Jin Je, Myung Chang Kang
Journal of Korean Powder Metallurgy Institute.2015; 22(3): 169. CrossRef
Comparison of Micro Trench Machining Characteristics with Nonferrous Metal and Polymer using Single Diamond Cutting Tool
Hwan-Jin Choi, Eun-Chae Jeon, Doo-Sun Choi, Tae-Jin Je, Myung-Chang Kang
Journal of Korean Powder Metallurgy Institute.2013; 20(5): 355. CrossRef
Comparison of Machinability Between PCD Tool and SCD Tool for Large Area Mirror Surface Machining Using Multi-tool by Planer
Chang-Eui Kim, Hwan-Jin Choi, Eun-Chae Jeon, Tae-Jin Je, Myung-Chang Kang
Journal of Korean Powder Metallurgy Institute.2013; 20(4): 297. CrossRef
Consolidation of mixed diamond and cobalt granule powders by magnetic pulsed compaction
Jung G. Lee, M.K. Lee, S.J. Hong, H.W. Lee, S.P. Pyun, C.K. Rhee
Materials Letters.2010; 64(1): 35. CrossRef

Densification of Al₂O₃ Nanopowder by Magnetic Pulsed Compaction and Their Properties: R.C. Kang, M.K. Lee, W.W. Kim, C.K. Rhee, S.J. Hong; J Korean Powder Metall Inst. 2008;15(1):37-45.; DOI: https://doi.org/10.4150/KPMI.2008.15.1.037

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This article presents the challenges toward the successful consolidation of Al_2O_3 nanopowder using magnetic pulsed compaction (MPC). In this research the ultrafine-structured Al_2O_3 bulks have been fabricated by the combined application of magnetic pulsed compaction (MPC) and subsequent sintering, and their properties were investigated. The obtained density of Al_2O_3 bulk prepared by the combined processes was increased with increasing MPC pressure from 0.5 to 1.25 GPa. Relatively higher hardness and fracture toughness in the MPCed specimen at 1.25 GPa were attributed to the retention of the nanostructure in the consolidated bulk without cracks. The higher fracture toughness could be attributed to the crack deflection by homogeneous distribution and the retention of nanostructure, regardless of the presence of porosities. In addition, the as consolidated Al_2O_3 bulk using magnetic pulsed compaction showed enhanced breakdown voltage.

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Microstructure and Characteristics of Ag-SnO2Contact Materials Prepared by Magnetic Pulsed Compaction
J.S. Park, Y.J. Kim, M.H. Lee, H.S. Lee, S.J. Hong, J.K. Lee
Journal of Korean Powder Metallurgy Institute.2011; 18(4): 372. CrossRef
The Effect of Ti Powder addition on Compaction Behavior of TiO2Nano Powder
Jin-Sub Park, Hyo-Seob Kim, Ki-Seok Lee, Jeong-Goo Lee, Chang-Kyu Rhee, Soon-Jik Hong
Journal of Korean Powder Metallurgy Institute.2009; 16(3): 223. CrossRef

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