• Journal of the Korean institute of surface engineering
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• v.43 no.2
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• pp.64-72
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• 2010

CuSnZn electroplating was investigated as alternative to Ni plating. Evaluation of electrolyte and plating process was performed to control physical characteristics of the film, and to collect practical data for application. Hull-cell test was conducted for basic comparison of two commercialized products and developed product. Based on hull-cell test results, long term test of three electrolytes was performed. Various analysis on long term tested electrolyte and samples have been done. Reliable and practical data was collected using FE-SEM (FEI, Sirion), EDX (ThermoNoran SIX-200E), ICP Spectrometer (GBC Scientifi c, Integra XL), FIB (FEI, Nova600) for anlysis. Physical analysis and reliability test of the long term tested film were also carried out. Through this investigation plating time, plating speed, electrolyte composition, electrolyte metal consumption, hardness and corrosion resistance has been compared. This set of data is used to predict and control the chemical composition of the film and modify the physical characteristics of the CuSnZn alloy.

• Korean Journal of Metals and Materials
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• v.48 no.8
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• pp.749-756
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• 2010

Low carbon steels were oxidized isothermally at 1050 and $1180^{\circ}C$ for 4 hr in air in order to determine the effect of alloying elements Si, S, Cu, Sn, and Ni on oxidation. For oxidation resistance of low carbon steels, the beneficial elements were Si, Cu, and Ni, whereas the harmful elements were S and Sn. The most active alloying element, Si, was scattered inside the oxide scale, at the scale-alloy interface, and as an internal oxide precipitate. The relatively noble elements such as Cu and Ni tended to weakly segregate at the scale-alloy interface. Sulfur and Sn were weakly, uniformly distributed inside the oxide scale. Excessively thick, non-adherent scales containing interconnected pores formed at $1180^{\circ}C$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.104-107
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• 2001

In order to investigate the effect of Ge addition to the Cu matrix on the microstructure and the critical current density, four kinds of internal tin processed Nb$_3$Sn strands with pure Cu and Cu 0.2, 0.4, 0.6 wt % Ge alloys were drawn to 0.8 mm diameter. The microstructure and critical current of internal tin processed Nb$_3$Sn wires that were heat treated at temperatures ranging from 68$0^{\circ}C$ to 74$0^{\circ}C$ for 240h were investigated. The Ge addition to the matrix did not make workability worse. A Ge rich layer in the Cu-Ge matrix suppressed the growth of the Nb$_3$Sn layer and promoted grain coarsening. The greater the Ge content in the matrix, the lower the net Jc result after Nb$_3$sn reaction heat treatment. There was no significant variation in Jc observed with heat treatment temperature ranging from 68$0^{\circ}C$ to 74$0^{\circ}C$. The values of AC loss of Ge added wires were decreased to 40 % compare with no addition wire. Low AC loss was due to segregation of Ge rich layer in the Cu-Ge matrix. If Ge added wire with thin Nb filaments were fabricated, slow diffusion rate of Sn would be overcome and decreased AC loss that is weak Point of internal tin method.

• Proceedings of the KWS Conference
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• 2006.10a
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• pp.136-138
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• 2006

Recently a lots of problems have observed in high densified and high integrated electronic components. One of them is ion migration phenomena, which induce the electrical short of electrical circuit. Ion migration phenomena has been observed in the field of exposing the specific environment and using for a long time. Also as the RoHS restriction was started in July 1st, 2006, Pb-free solder was utilized in electronics assemblies. In this case, it is very important to compatible between components and printed circuit board(PCB), thus surface treatment materials of PCB was changed to Sn, Sn-3.0Ag-0.5Cu, Cu. Therefore these new application become to need to reevaluate the sensitivity about electrochemical ion migration. This study was evaluated the occurrence time of electrochemical ion migration using by water drop test. We utilized PCB(printed circuit board) having a comb pattern as follows 0.1, 0.318, 0.5, 1.0 mm pattern distance. Sn-3.0Ag-0.5Cu and Sn-37Pb were electroplated on the comb pattern. 6.5V and 15.0V were applied in the comb pattern and then we measured the electrical short time causing by occurring the ion migration. In these results, we evaluate the sensitivity and derived the prediction models of ion migration occurrence time depending on the pattern materials, applied voltage and pattern spacing of PCB conductor.

• Journal of the Korean Society for Heat Treatment
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• v.17 no.1
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• pp.2-9
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• 2004

This study has examined the metallurgical microstructures and alloy compositions of 3 bronze artifacts, a vessel, a spoon and a chopstick, manufactured in the Koryo Dynasty. The results show that they were made from Cu-Sn alloys whose Sn content ranges from 22 to 24% by weight. It is of significant importance to find that they were all given special thermo-mechanical treatments during their manufacturing. It has been found that the Koryo bronze workers were well aware of the mechanical properties of ${\alpha}$, ${\beta}$, ${\gamma}$ and ${\delta}$ phases that appear in the Cu-Sn alloys. Knowing how to promote or suppress the formation of each phase, they were able to find proper alloy compositions and temperatures for the high Sn alloys to be successfully forged. The present study will detail the Koryo bronze technology as estimated from the microstructures of the 3 bronze artifacts. The results of the reproduction experiments with Cu-24%Sn will also be presented to explain how the microstructures develop and to estimate the mechanical properties of each phase.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.1
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• pp.31-37
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• 2021

Sn-3wt%Ag-0.5wt%Cu (SAC305) solder is most popular solder in electronics industry. However, SAC305 has also drawbacks such as growth of β-Sn phase, intermetallic compounds (IMCs) of Ag3Sn, Cu6Sn5 and Cu3Sn which can result in deterioration of solder joints in terms of metallurgically, mechanically and electrically. Thus, improvement of SAC305 solders have been investigated continuously by addition of alloying elements, nano-particles and etc. In this paper, recent improvements of SAC solders including nano-composite alloys and related solderabilty and metallurgical and mechanical properties are investigated.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.86.1-86.1
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• 2010

Cu2ZnSnSe4는 CIS 태양전지의 In 대체 물질계로 주목을 받고 있는 저가형 태양전지 재료로 장차 차세대 태양전지 재료로 응용이 기대되고 있다. 그러나 에너지 밴드갭이 0.9~1.1eV로 다소 낮아 태양전지 광흡수층 재료로 사용하기 위해서는 wide band gab화 처리가 필요하다. 본 연구에서는 CZTSe에 S를 첨가하여 에너지 밴드갭을 확장하고자 하며, S의 첨가가 CZTSe 박막의 특성에 미치는 영향에 대하여 조사하였다. 실험의 편의성을 도모하고자 펄스레이저 법을 사용하여 증착하였다. 박막 조성 제어에는 Cu, Zn, Sn, Se, S 분말을 볼밀로 분쇄, 혼합하여 균질 혼합상 프리커서를 제조하고 이를 Cold Isostatic Press(CIP) 성형하여 Source target을 사용하였다. Pulsed YAG-Laser를 사용하여 soda lime glass상에 증착하고 조성, 구조, 조직을 관찰하고 에너지 밴드갭, 광흡수계수, 면저항, 전하밀도 등 특성을 조사하였다.

• Transactions of Materials Processing
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• v.7 no.5
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• pp.481-488
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• 1998

The active metal brazing was applied to bond Alumina and Ni-Cr steel by Ag-Cu-Zr-Sn alloy and the interfacial microstructure and reaction mechanism were investigated. Polycrystalline monoclinic $ZrO_2$ with a very fine grain of 100-150 nm formed at the alumina grain boundary contacted with Zr segregation layer at the interface. The $ZrO_2$ layer containing the inclusions and cracks were developed at the boundary of inclusion/$ZrO_2$ due to the difference in specific volume. The development of $ZrO_2$ at the interface was successfully explained by the preferential penetration of $ZrO_2$ at the interface was successfully explained by the preferential penetration of Zr atoms a higher concentration of oxygen and a high diffusion rate of Al ions into molten brazing alloy.

• Korean Journal of Materials Research
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• v.5 no.4
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• pp.490-500
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• 1995

다이아몬드와는 달리 CBN은 철족 재료 연삭시 화학적 마모가 거의 없다. 이러한 장점으로 인해 CBN휠이 철강 재료 연삭에 널리 사용되고 잇는 것이다. 그러나 CBN 휠의 성능은 CBN을 붙잡고 있는 결합제에 크게 의존한다. 오늘날 널리 사용되는 결합제인 주석 청동 합금은 내마모성에 한계가 있다. 주석 청동 합금의 내마모성을 증대시키기 위해 Co를 첨가하였다. 이러한 기지합금에 젖음성을 향사시키기위해 Co코팅 CBN을 사용하였다. 기지합금에 20%co를 첨가한 것이 입계에서 연속적인 $\delta$상생성, 취성 증가에 따라 자생작용이 활발하였다. 가장 높은 연삭비를 나타낸 것은 Cu-15wt%Sn, cu-33wt%Sn, co를 40:40:20으로 제작한 휠이었다.

• Proceedings of the KWS Conference
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• 2006.10a
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• pp.184-186
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• 2006

Sn-3Ag-0.5Cu is one of candidate as an alternative approach to conventional lead-tin solder. In order to evaluate that creep characteristic of QFP, we used Sn-3Ag-0.5Cu where the operating temperature is $100^{\circ}C$. The specimens were loaded to failure at average pull strength in the range of 20% to 25%, X-ray machine is used to eliminate effect of void. In this paper, relation of time-displacement and steady state creep rate was studied, and used to analyze the experimental result.