Journal of Powder Materials

Young-Jung Lee

4 Articles

The Formation of Hybridized Porous Structure of Al Alloy by Alkali Surface Modification: Young-Ik Seo, Young-Moon Kim, Young-Jung Lee, Dae-Gun Kim, Kyu-Hwan Lee, Young-Do Kim; J Korean Powder Metall Inst. 2009;16(1):22-27.; DOI: https://doi.org/10.4150/KPMI.2009.16.1.022

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To improve the filtration efficiency of porous materials used in filters, an extensive specific surface area is required to serve as a site for adsorption of impurities. In this paper, a method for creating a hybridized porous alloy using a powder metallurgical technique to build macropores in an Al-4 wt.% Cu alloy and subsequent surface modification for a microporous surface with a considerably increased specific surface area is suggested. The macropore structure was controlled by granulation, compacting pressure, and sintering; the micropore structure was obtained by a surface modification using a dilute NaOH solution. The specific surface area of surface-modified specimen increased about 10 times compare to as-sintered specimen that comprised of the macropore structure. Also, the surface-modified specimens showed a remarkable increase in micropores larger than 10 nm. Such a hybridized porous structure has potential for application in water and air purification filters, as well as membrane pre-treatment and catalysis.

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Development of Vacuum Thin-Film-Forming Mold using Porous Aluminum
Hyung-Sun Kang, Sunghyun Lee
Journal of the Korean Society of Manufacturing Technology Engineers.2020; 29(6): 435. CrossRef
Phosphorus removal from wastewater by ionic exchange using a surface-modified Al alloy filter
Young Ik Seo, Ki Ho Hong, Se Hoon Kim, Duk Chang, Kyu Hwan Lee, Young Do Kim
Journal of Industrial and Engineering Chemistry.2013; 19(3): 744. CrossRef

Fabrication of ZnS-SiO₂ Composite and its Mechanical Properties: Dae-Hoon Shin, Gil-Su Kim, Young-Jung Lee, Hoon Cho, Young-Do Kim; J Korean Powder Metall Inst. 2008;15(1):1-5.; DOI: https://doi.org/10.4150/KPMI.2008.15.1.001

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Abstract PDF: ZnS-SiO_2 composite is normally used for sputtering target. In recent years, high sputtering power for higher deposition rate often causes crack formation of the target. Therefore the target material is required that the sintered target material should have high crack resistance, excellent strength and a homogeneous microstructure with high sintered density. In this study, raw ZnS and ZnS-SiO_2 powders prepared by a 3-D mixer or high energy ball-milling were successfully densified by spark plasma sintering, the effective densification method of hard-to-sinter materials in a short time. After sintering, the fracture toughness was measured by the indentation fracture (IF) method. Due to the effect of crack deflection by the residual stress occurred by the second phase of fine SiO_2, the hardness and fracture toughness reached to 3.031 GPa and 1.014MPacdotm1/2, respectively.

Compaction Properties of Fe Powder Fabricated by Warm Compaction: Se-Hoon Kim, Young-Jung Lee, Jea-Sung Lee, Young-Do Kim; J Korean Powder Metall Inst. 2007;14(3):185-189.; DOI: https://doi.org/10.4150/KPMI.2007.14.3.185

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Abstract PDF: Various approaches have been proposed to increase the green density. Warm compaction method has been used for the reduction of residual stress, the improvement of magnetic properties and the higher densities. In this work, the effect of warm compaction on green density of Fe powder was investigated. After ball-milling of Fe oxide powder for 30 hours, Fe oxide powder was reduced through the hydrogen reduction process. The pure Fe powder and polymer binder were mixed by 3-D tubular mixer. And then the mixed powder was warm-compacted with various compaction pressure and binder contents. The green density of specimen was added polyvinyl binder was higher than any other specimens.

Synthesis of Nanostructured Fe-Co Alloy Powders from Metal Salts: Young-Jung Lee, Jea-Sung Lee, Young-Ik Seo, Young-Do Kim; J Korean Powder Metall Inst. 2006;13(5):336-339.; DOI: https://doi.org/10.4150/KPMI.2006.13.5.336

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Abstract PDF: Magnetic properties of nanostructured materials are affected in complicated manner by their microstructure such as pain size (or particle size), internal strain and crystal structure. Thus, studies on the synthesis of nanostructured materials with controlled microstructure are necessary fur a significant improvement in magnetic properties. In the present work, nanostructured Fe-Co alloy powders with a grain size of 50 nm were successfully fabricated from the powder mixtures of (99.9% purity) FeCl_2 and CoCl_2 by chemical solution mixing and hydrogen reduction.

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