• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1497-1500
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• 2005

This paper accomplished the basic research using the hydrostatic extrusion to make the nano-grained bulk material. It was carried out a hot hydrostatic extrusion using the hipped bulk Al-7.5%Mg that was taken from University of California, Davis. in order to investigate the effect of the hot isostatic extrusion. The tensile tests for the hipped bulk Al-7.5%Mg and the extruded one was executed and the results was compared.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.848-849
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• 2006

Bulk metallic glass (BMG) composites combining a $Cu_{54}Ni_6Zr_{22}Ti_{18}$ matrix with brass powders or $Zr_{62}A_{l8}Ni_{13}Cu_{17}$ metallic glass powders were fabricated by spark plasma sintering. The brass powders and Zr-based metallic glass powders added for the enhancement of plasticity are well distributed homogeneously in the Cu-based metallic glass matrix after consolidation. The BMG composites show macroscopic plasticity after yielding, and the plastic strain increased to around 2% without a decrease in strength for the composite material containing 20 vol% Zr-based amorphous powders. The proper combination of strength and plasticity in the BMG composites was obtained by introducing a second phase in the metallic glass matrix.

• Proceedings of the Korean Magnestics Society Conference
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• 2003.06a
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• pp.214-215
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• 2003

• Nano
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• v.13 no.12
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• pp.1850138.1-1850138.6
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• 2018

Two-dimensional (2D) or layered materials have a great potential for applications in energy storage, catalysis, optoelectronics and gas separation. Fabricating novel 2D or quasi-2D layered materials composed of relatively abundant and inexpensive atomic species is an important issue for practical usage in industry. Here, we suggest the layer-structured AlOOH (Boehmite) as a promising candidate for such applications. Boehmite is a well-known layer-structured material and a single-layer can be exfoliated from the bulk boehmite by breaking the interlayer hydrogen bonding. We study atomic and electronic band structures of both bulk and single-layer boehmite, and also obtain the single-layer exfoliation energy using first-principles calculations.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.3-4
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• 2006

본 논문에서는 nano-scale CMOSFET을 위해 Boron Cluster ($B_{18}H_{22}$)가 이온주입된 SOI 와 Bulk 기판들 이용하였으며 실리사이드의 열 안정성 개선을 위해 Ni-V을 증착한 것과 순수 Ni을 증착한 것을 비교 분석 하였다. 결과 SOI위에 Ni-V을 증착한 것이 제일 낮은 면 저항을 보여주었고 반대로 Bulk위에는 제일 높은 면 저항을 보여 주었다. 단면을 측정한 결과 SOI 위에 Ni-V을 증착한 동일 조건의 Ni보다 Silicide의 두께가 두껍게 형성된 것을 확인하였다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.6
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• pp.487-490
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• 2007

In this paper, the formation and thermal stability characteristics of Ni silicide using Ni-V alloy on Boron cluster ($B_{18}H_{22}$) implanted bulk and SOI substrate were examined in comparison with pure Ni for nano-scale CMOSFET. The Ni silicide using Ni-V alloy on $B_{18}H_{22}$ implanted SOI substrate after high temperature post-silicidation annealing showed the lower sheet resistance, no agglomeration interface image and lower surface roughness than that using pure Ni. The thermal stability of Ni silicide was improved by using Ni-V alloy on $B_{18}H_{22}$ implanted SOI substrate.

• Composites Research
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• v.32 no.3
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• pp.141-147
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• 2019

In this study, micro-sized and nano-sized pure aluminum (Al) powders were compressed by unidirectional pressure at room temperature. Although neither type of Al bulk was heated, they had a high relative density and improved mechanical properties. The microstructural analysis showed a difference in the process of densification according to particle size, and the mechanical properties were measured by the Vickers hardness test and the nano indentation test. The Vickers hardness of micro Al and nano Al fabricated in this study was five to eight times that of ordinary Al. The grain refinement effect was considered to be one of the strengthening factors, and the Hall-Petch equation was introduced to analyze the improved hardness caused by grain size reduction. In addition, the effect of particle size and dispersion of aluminum oxide in the bulk were additionally considered. Based on these results, the present study facilitates the examination of the effect of particle size on the mechanical properties of compacted bulk fabricated by the powder metallurgy method and suggests the possible way to improve the mechanical properties of nano-crystalline powders.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.10
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• pp.7-13
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• 2004

• Journal of Powder Materials
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• v.21 no.3
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• pp.196-201
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• 2014

In this study, nanocrystalline Cu-Ni bulk materials with various compositions were cold compacted by a shock compaction method using a single-stage gas gun system. Since the oxide layers on powder surface disturbs bonding between powder particles during the shock compaction process, each nanopowder was hydrogen-reduced to remove the oxide layers. X-ray peak analysis shows that hydrogen reduction successfully removed the oxide layers from the nano powders. For the shock compaction process, mixed powder samples with various compositions were prepared using a roller mixer. After the shock compaction process, the density of specimens increased up to 95% of the relative density. Longitudinal cross-sections of the shock compacted specimen demonstrates that a boundary between two powders are clearly distinguished and agglomerated powder particles remained in the compacted bulk. Internal crack tended to decrease with an increase in volumetric ratio of nano Cu powders in compacted bulk, showing that nano Cu powders has a higher coherency than nano Ni powders. On the other hand, hardness results are dominated by volume fraction of the nano Ni powder. The crystalline size of the shock compacted bulk materials was greatly reduced from the initial powder crystalline size since the shock wave severely deformed the powders.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.545-545
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• 2007

Recently, innovative process has been investigated in order to replace the conventional high-cost micro patterning processes on the electronic products. To produce desirable profit margins from this low cost products, printed circuit board(PCB), will require dramatic changes in the current manufacturing philosophies and processes. Innovative process using metal nano particles replaces the current industry standard of subtractive etched of copper as a highly efficient way to produce robust circuitry on low cost substrates. An advantage of using metal nano particles process in patterned conductive line manufacturing is that the process is additive. Material is only deposited in desired locations, thereby reducing the amount of chemical and material waste. Simply, it just draws on the substrate as glass epoxy or polyimide with metal nano particles. Particles, when their size becomes nano-meter scale, show some specific characteristics such as enhanced reactivity of surface atoms, decrease in melting point, high electric conductivity compared with the bulk. Melting temperature of metal gets low, the metal nano particles could be formated onto polymer substrates and sintered under $300^{\circ}C$, which would be applied in PCB. It can be getting the metal line of excellent electric conductivity.