• 한국기계가공학회지
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• 제10권6호
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• pp.89-94
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• 2011

The wear characteristics between nonmetal and metals have been investigated using a disc on disc system. The specimens of nonmetal are made by the nylon and teflon materials. The specimens of the metal are used as eight kinds of along their hardness. The kinds of metals are copper(Hv96), aluminum(Hv186), brass(Hv234), aluminum bronze(Hv294), stainless steel(Hv327), annealing mild steel(Hv345), mild steel(Hv372), Hard steel(Hv434). In this study, a upper and lower specimens have been used the same size and shape. Using experimental data we figured the relationship between friction coefficient of nonmetal and metals. We figured the relationship between friction temperature of nonmetal and metals. The result had been verified a wear characteristics of nonmetal and metals in the wear tests.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.494-497
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• 2003

We report the dark spots in organic light emitting diodes by using a near-field scanning microwave microscope. Devices structure was glass / indium-tin-oxide(ITO) / copper-pthalocyiane(Cu-Pc) / tris-(8-hydroquinoline)aluminum(Alq3) / aluminum(Al). We made artificial dark spots by using a etching technique on a ITO substrate. Near-field scanning microwave microscope images and reflective coefficient of dark spots were measured and compared by the change of various applied voltage changes 0-15V.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.233-236
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• 2005

Rotor in small-medium induction motor has been usually manufactured by aluminum diecasting. In order to improve efficiency of induction motors, newly developed Cu-Ca alloys have been investigated. The electrical conductivity in the Cu alloys containing Ca less than $1.0wt\%$ was higher than $80\%$ IACS. Cu-Ca alloy is desirable for the thixoforming process because it has wide semi-solid range over $150^{\circ}C$. In this study, Cu-rotor with thixoforming process was developed to replace the conventional aluminum diecasting rotor. Analysis microstructure of thixoforming rotor. effect of incomplete filling defect on the efficiency of induction motor was discussed.

• 한국표면공학회지
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• 제33권5호
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• pp.329-338
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• 2000

In this study, as an effort to improve the brittlement of coating layer, aluminum bronze coatings formed on steel substrates by arc jet spray process were subjected to post heat treatment. After each treatment, mechanical properties such as hardness, and UTS, and microstructural characterization of the specimens were investigated. The results showed that the hardness in the coatings slightly decreased with increasing heat treatment tine and temperature. The UTS of as-sprayed coatings was 4.31kgf/$\textrm{mm}^2$ and slightly increased to 5.51kgf/$\textrm{mm}^2$ after heat treatment at $900^{\circ}C$ for 120min. On the other hand, the interdiffusion of copper and aluminum particles after heat treatment lead to decrease of the porosity density and increase the bond strength.

• 한국해양공학회지
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• 제23권3호
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• pp.35-39
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• 2009

The main objective of this study was to investigate fiber reinforced composite materials (FRCM) with electromagnetic shielding characteristics using aluminum (Al) film and copper (Cu) meshes. This study investigated the electromagnetic interference (EMI) shielding effectiveness (SE) of fiber reinforced composites filled with Al film, Cu meshes, and nano carbon black as hybrid conductive fillers to provide the electromagnetic shielding property of the fiber reinforced composites. The coaxial transmission line method of ASTM D 4935-89 was used to measure the EMI shielding effectiveness of composites in the frequency range of 300 MHz to 1.5 GHz. The variations of SE of FRCM with Al film, fine Cu, and general Cu meshes are described. The results indicate that the FRCM having Al film exhibited up to 75 dB of SE at 1.5 GHz.

• 한국분말재료학회지
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• 제21권1호
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• pp.39-43
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• 2014

Bulk nanostructured copper was fabricated by a shock compaction method using the planar shock wave generated by a single gas gun system. Nano sized powders, average diameter of 100 nm, were compacted into the capsule and target die, which were designed to eliminate the effect of undesired shock wave, and then impacted with an aluminum alloy target at 400 m/s. Microstructure and mechanical properties of the shock compact specimen were analyzed using an optical microscope (OM), scanning electron microscope (SEM), and micro indentation. Hardness results showed low values (approximately 45~80 Hv) similar or slightly higher than those of conventional coarse grained commercial purity copper. This result indicates the poor quality of bonding between particles. Images from OM and SEM also confirmed that no strong bonding was achieved between them due to the insufficient energy and surface oxygen layer of the powders.

• 대한기계학회논문집B
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• 제35권1호
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• pp.43-51
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• 2011

수평관 외부에서 발생하는 자연대류 열전달 현상을 실험적으로 연구하였다. 연구의 목적은 구리 도금계를 채택한 유사성실험방법론이 적용가능한지 확인하는 것과 수평관의 지름과 각도에 따라 달라지는 국부열전달을 시각화하는 것이었다. 구리의 전기도금계를 사용하면 양극에서 생성된 구리이온은 대류와 확산을 통하여 음극으로 이동되어 환원되는데 이는 열전달을 모사하게 된다. 구리와 색깔이 다른 알루미늄을 음극으로 채택함으로써 각도에 따라 환원되어 석출된 구리의 양을 시각화 할 수 있었다. 수평관의 직경은 0.01m에서 0.15m이었고 이는 $Ra_D\;=\;1.73{\times}10^7\;{\sim}\;5.69{\times}10^{11}$에 해당한다. 실험결과는 기존에 알려진 열전달 상관식과 일치하였다. 알루미늄 음극에 도금된 구리의 패턴은 Kitamura에 의해 액체결정온도측정법으로 시각화한 결과와 매우 잘 일치 하였다.

• 마이크로전자및패키징학회지
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• 제25권2호
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• pp.9-17
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• 2018

Aluminum (Al) and its alloys have been used widely in a variety of industries such as structural, electronic, aerospace, and particularly automotive industries due to their lightweight characteristic, outstanding ductility, formability, high oxidation and corrosion resistance, and high thermal and electrical conductivity. Al have different kinds of alloys according to the various additional elements system and they should be selected properly depending on their effectiveness and suitability for their particular purpose. The major elements for Al alloys are silicon (Si), magnesium (Mg), manganese (Mn), copper (Cu), and zinc (Zn). In order for Al alloys to use for each industry, it is necessary to study of Al to Al joining and/or the Al to dissimilar materials joining to combine the individual parts into one. Many studies on joining technologies about Al to Al and Al to dissimilar materials have been performed such as press joining, bolted joint, welding, soldering, riveting, adhesive bonding, and brazing. This study reviews a variety of Al alloys and their joining method including its principles and properties with recent trends.

• Journal of Welding and Joining
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• 제17권5호
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• pp.107-115
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• 1999

The objective of this research was to study the formation of the thick hardened layer with the addition of metal powder(Cu) and ceramics powders(TiC) on the aluminum 5083 alloys by plasma transferred arc process(PTA process) and to characterize the effect of overlaying conditions on the overlaid layer formation. This was followed by investigating the microstructures of the overlaid layers and mechanical properties such as hardness and wear resistance. The overlaid layer containing copper powder was alloyed and intermetallic compound($CuAl_2$) was formed. The overlaid layers with high melting point TiC powders, however, did not react with base metal. Wear resistance of the alloyed layer was remarkably improved by the formation of $CuAl_2$, precipitate phase, which prevented wear of base aluminum alloys and at higher wear speed, accelerated sliding of the counter part. Wear resistance of the composite layer was also remarkably improved because TiC powder act as a load barring element and Fe debris fragments detached from the counter part act as a solid lubricant on the contact surface.

• 한국분말재료학회지
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• 제30권4호
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• pp.339-345
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• 2023

This study investigates the melting point and brazing properties of the aluminum (Al)-copper (Cu)-silicon (Si)-tin (Sn) alloy fabricated for low-temperature brazing based on the alloy design. Specifically, the Al-20Cu-10Si-Sn alloy is examined and confirmed to possess a melting point of approximately 520℃. Analysis of the melting point of the alloy based on composition reveals that the melting temperature tends to decrease with increasing Cu and Si content, along with a corresponding decrease as the Sn content rises. This study verifies that the Al-20Cu-10Si-5Sn alloy exhibits high liquidity and favorable mechanical properties for brazing through the joint gap filling test and Vickers hardness measurements. Additionally, a powder fabricated using the Al-20Cu-10Si-5Sn alloy demonstrates a melting point of around 515℃ following melting point analysis. Consequently, it is deemed highly suitable for use as a low-temperature Al brazing material.