• 한국입자에어로졸학회지
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• 제8권2호
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• pp.83-88
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• 2012

The electrical wire explosion process in liquid media is promising for nano-sized metal and/or alloy particles. The hybrid Pt/Fe-Cr-Al and Pt/Ni-Cr-Fe nanoparticles for exhaust emission control system are synthesized by electrical wire explosion process in liquid media. The alloy powders have spherical shape and nanometer size. According to the wire component, while Pt/Fe-Cr-Al nanoparticles are shown the well dispersed Pt on the Fe-Cr-Al core particle, Pt/Ni-Cr-Fe nanoparticles are shown the partially separated Pt on the Ni-Cr-Fe core particle. Morphologies and component of two kinds of hybrid nano catalyst particles were characterized by transmission electron microscope and energy dispersive X-ray spectroscopy analysis.

• 한국산업융합학회 논문집
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• 제14권2호
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• pp.73-78
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• 2011

Power consumption for wire gauge impeller in cylindrical agitated vessel was measured over a wide range of Reynolds number from laminar to turbulent flow regions. The power correlation were obtained agitation power input of WM4 at gassing condition in turbulent region, at gassing condition in transient region and at gassing condition in laminar region. Also the compared with effect of impeller diameter and blade width on agitation power input at gassing condition in turbulent region, at gassing condition in transient region and at gassing condition in laminar region.

• 한국분말재료학회지
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• 제14권1호
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• pp.56-62
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• 2007

Getter property of nano-sized metallic powders was evaluated as a possible candidate for the future getter material. For the purpose, Ti powders of about 50 nm were prepared by electrical wire explosion. Commercial Ti powders of about 22 micrometer were tested as well for comparison. The room-temperature hydrogen-sorption speed of nano-sized Ti powders was $1.34\;L/sec{\cdot}cm^{2}$ which was more than 4 times higher than that of micron-sized ones. The value is comparable to or even higher than those of commercial products. Its sorption speed increases with activation temperature up to $500^{\circ}C$ above which it deteriorates due to low-temperature sintering effect of nano-sized particles.

• 한국분말재료학회지
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• 제18권2호
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• pp.112-121
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• 2011

This study investigated the effect of solvent on the fabrication of Ni-free Fe-based alloy nano powders by employing the PWE (pulsed wire evaporation) in liquid and compared the alloy particles fabricated by three different methods (PWE in liquid, PWE in Ar, plasma arc discharge), for high temperature oxidation-resistant metallic porous body for high temperature soot filter system. Three different solvents (ethanol, acetone, distilled water) of liquid were adapted in PWE in liquid process, while X-ray diffraction (XRD), field emission scanning microscope (FE-SEM), and transmission electron microscope (TEM) were used to investigate the characteristics of the Fe-Cr-Al nano powders. The alloy powder synthesized by PWE in ethanol has good particle size and no surface oxidation compared to that of distilled water. Since the Fe-based alloy powders, which were fabricated by PWE in Ar and PAD process, showed surface oxidation by TEM analysis, the PWE in ethanol is the best way to fabricate Fe-based alloy nano powder.

• Bulletin of the Korean Chemical Society
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• 제34권6호
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• pp.1845-1847
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• 2013

The lateral photovoltaic effect (LPE) can be observed in semiconductors by irradiating a light spot position between electrodes on sample's surface. Because lateral photovoltaic voltage (LPV) is sensitively changed by light spot position, a LPE device has been tried as a position-sensitive detector. This study discusses the correlation between LPV and conductivity in p-type silicon and nano-structured Au deposited p-type silicon (nano-Au silicon), respectively. Conductivity measurement of the sample was carried out using the four-wire method to eliminate contact resistance, and conductivity dependence on LPV was simultaneously measured by changing the light irradiation position. The result showed a strong correlation between conductivity and LPV in the p-type silicon sample. The correlation coefficient was 0.87. The correlation coefficient between LPV and conductivity for the nano-Au silicon sample was 0.41.

• 한국분말재료학회지
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• 제9권6호
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• pp.433-440
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• 2002

Synthesis and compaction of Al-base nano powders by pulsed discharge method were investigated. The aluminum based powders with 50 to 200 nm of diameter were produced by pulsed wire evaporation method. The powders were covered with very thin oxide layer. The perspective process for the compaction and sintering of nanostructured metal-based materials stable in a wide temperature range can be seen in the densification of nano-sized metal powders with uniformly distributed hard ceramic particles. The promising approach lies in utilization of natural uniform mixtures of metal and ceramic phases, e.g. partially oxidized metal powders as fabricated in our synthesis method. Their particles consist of metal grains coated with oxide films. To construct a metal-matrix material from such powder, it is necessary to destroy the hard oxide coatings of particles during the compaction process. This goal was realized in our experiments with intensive magnetic pulsed compaction of aluminum nanopowders passivated in air.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2007년도 The 1st International Symposium on Advanced Magnetic Materials
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• pp.124.2-124.2
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• 2007

• 접착 및 계면
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• 제25권2호
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• pp.63-68
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• 2024

본 연구에서는 반도체 패키지용 와이어 본딩 공정에서 금(Au) wire의 표면처리에 적용되는 린스의 종류에 따른 Au wire의 오염 현상을 확인하고자 하였다. Au wire의 표면처리를 위해 실리콘(Si) 성분이 함유된 린스와 유기 계통으로만 이루어진 린스를 주로 사용하고 있으며, 실제 영향성을 확인하기 위해 두 종류의 1.0wt% 린스 용액으로 Au wire에 표면처리를 진행하였다. 이후, 반도체 공정에서 발생할 수 있는 Si 성분이 포함된 분진과의 반응성을 확인하기 위한 모사 실험을 진행하였다. 그 결과, optical microscopy(OM) 및 scanning electron microscopy(SEM) 분석을 통해 Si 성분이 함유된 린스로 표면처리한 Au wire의 경우 분진이 다량 흡착되었으며, 유기 계통으로만 이루어진 린스로 표면처리한 Au wire에는 소량의 분진이 흡착된 것을 확인하였다. 이는 Si 성분이 함유된 린스의 경우 상대적으로 극성을 띠기에, 주성분이 극성인 분진과 극성 상호작용을 일으키기 때문이다. 따라서 Si 성분이 존재하지 않는 린스를 사용하여 Au wire를 표면처리할 경우 분진에 의한 오염 현상이 감소하여 실제 와이어 본딩 공정에서 불량률을 낮추는 효과를 볼 수 있을 것으로 기대한다.

• Transactions on Electrical and Electronic Materials
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• 제17권3호
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• pp.163-167
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• 2016

Inverter surge resistant enameled wire was prepared with an organic/inorganic hybrid nanocomposite, and the effect of ambient temperature on the insulation lifetime of the enameled wire in the form of twisted pair was studied by a withstanding voltage tester. The organic polymer was Polyesterimide-polyamideimide (EI/AI) and the inorganic material was a Nano-sized silica (average particle size : 15 nm). The enamel thickness was 50 μm and the ambient temperature was 100, 150, 200, and 250, respectively. Transmission electron microscopy (TEM) observation showed that Nano-sized Silica were evenly dispersed in EI/AI. There were many air gaps in a twisted pair, therefore, when voltage was applied to the twisted pair, enamel erosion took place in the air gap area because of partial discharge accordi, ng to Paschen’s law. As ambient temperature increased, insulation lifetime decreased according to Arrhenius relationship, which was explained by the increasing mobility of polymer chains in EI or AI. And insulation breakdown voltage value at 10 kHz was 1,864.5 sec (31.1 min), which is 1.9 times higher than at 20 kHz, 981.6 sec (16.4 min).

• 한국표면공학회지
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• 제49권3호
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• pp.301-306
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• 2016

The effects of nanotexturing and post-etching on the reflection and quantum efficiency properties of diamond wire sawn (DWS) multicrystalline silicon (mc-Si) solar cell have been investigated. The chemical solutions, which are acidic etching solution (HF-$HNO_3$), metal assisted chemical etching (MAC etch) solutions ($AgNO_3$-HF-DI, HF-$H_2O_2$-DI) and post-etching solution (diluted KOH at $80^{\circ}C$), were used for micro- and nano-texturing at the surface of diamond wire sawn (DWS) mc-Si wafer. Experiments were performed with various post-etching time conditions in order to determine the optimized etching condition for solar cell. The reflectance of mc-Si wafer texturing with acidic etching solution showed a very high reflectance value of about 30% (w/o anti-reflection coating), which indicates the insufficient light absorption for solar cell. The formation of nano-texture on the surface of mc-Si contributed to the enhancement of light absorption. Also, post-etching time condition of 240 s was found adequate to the nano-texturing of mc-Si due to its high external quantum efficiency of about 30% at short wavelengths and high short circuit current density ($J_{sc}$) of $35.4mA/cm^2$.