• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1084-1085
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• 2006

We studied formation of nanostructured $TiB_2$-Cu composites under shock wave conditions. We investigated the influence of preliminary mechanical activation (MA) of Ti-B-Cu powder mixtures on the peculiarities of the reaction between Ti and B under shock wave. In the MA-ed mixture the reaction proceeded completely while in the non-activated mixture the reagents remained along with the product . titanium diboride. The size of titanium diboride particles in the central part of the compact was 100-300 nm.

• 한국분말재료학회지
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• 제15권2호
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• pp.101-106
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• 2008

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.

• 한국레이저가공학회지
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• 제5권2호
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• pp.31-38
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• 2002

This paper describes the process of nanoparticle synthesis by laser ablation of consolidated microparticles. We have generated nanoparticles by high-power pulsed laser ablation of Al, Cu and Ag microparticles using a Q-switched Nd:YAG laser (wavelength 355 nm, FWHM 5 ㎱, fluence 0.8∼2.0 J/㎠). Microparticles of mean diameter 18∼80 ㎛ are ablated in the ambient air The generated nanoparticles are collected on a glass substrate and the size distribution and morphology are examined using a scanning electron microscope and a transmission electron microscope. The effect of laser fluence and collector position on the distribution of particle size is investigated. The dynamics of ablation plume and shock wave is analyzed by monitoring the photoacoustic probe-beam deflection signal. Nanosecond time-resolved images of the ablation process are also obtained by laser flash shadowgraphy. Based on the experimental results, discussions are made on the dynamics of ablation plume.