• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.2
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• pp.94-98
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• 2017

In the past few years, Sn-3.0Ag-0.5Cu (weight%) solder composition has been a representative material to electronic industries as a replacement of Pb-base solder alloy. Therefore, extensive studies on process and/or reliability related with the composition have been reported. However, recent rapid rise in Ag price has demanded solder compositions of low Ag content. In this study, Sn-3.0Ag-0.5Cu solder bar sample was fabricated by melting of Sn, Ag and Cu metal powders. Crystal structure and element concentration were analyzed by XRD, optical microscope, FE-SEM and EDS. The Sn-3.0Ag-0.5Cu solder sample was composed of ${\beta}$-Sn, ${\varepsilon}-Ag_3Sn$ and ${\eta}-Cu_6Sn_5$ phases.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1660-1662
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• 1996

Superconducting current lead is one of the promising applications of the oxide high-Tc superconductors, because they have the advantage of decreasing heat conduction to low temperature region, comparing with a conventional cooper alloy lead. High critical current density is a key factor for the applications such as current lead. $(Bi,Pb)_{2}Sr_{2}Ca_{2}Cu_{3}O_{x}$ high Tc superconductor hase been investigated in terms of critical current density. Bi-2223 superconducting current lead made by CIP and solid state sintering process. Bi-2223 current lead that heat treated at $836\;^{\circ}C$ for 240 h in 1/13 $PO_2$ had over $500\;A/cm^2$ of critical current density at 77K. We knew that the superconducting properties of tube type current leads were better than rods type of them. And we investigated the relation of Bi-2223 formation and heat treatment condition by XRD and SEM analysis.

• Korean Journal of Materials Research
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• v.31 no.8
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• pp.471-479
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• 2021

The electrochemical reaction between lead borate glass frit doped with Sn metal filler and Ni-Cr wire of a J-type resistor during a term of Joule heating is investigated. The fusing behavior in which the Ni-Cr wire is melted is not observed for the control group but measured for the Sn-doped specimen under 30 V and 500 mA. The Sn-doped lead borate glass frit shows a fusing property compared with other metal-doped specimens. Meanwhile, the redox reaction significantly contributes to the fusing behavior due to the release of free electrons of the metal toward the glass. The electrons derived from the glass, which used Joule heat to reach the melting point of Ni-Cr wire, increase with increasing corrosion rate at interface of metal/glass. Finally, the confidence interval is 95 ± 1.95₉ %, and the adjusted regression coefficient, R in the optimal linear graph, is 0.93, reflecting 93% of the data and providing great potential for fusible resistor applications.

• Archives of design research
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• v.17 no.4
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• pp.241-250
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• 2004

In this research, the copper alloy plates C2200, C5210, C7701, C8113 were selected to make datum and to identify further usage of metal craft experimentation. For its experimentation, the general welding and TIG welding methods were researched; for 2nd experimentation, the Reticulation and Electroforming skill's differences in color and temperature were researched. With these methods 3 different kinds of works are introduced for sample studies. For this research, Dr. Lee, Dong-Woo who works in Poongsan Metal Co, supported 4 kinds of copper alloy metals. Which are Commercial bronze (Cu-Zn), Deoxidiged Copper(Cu-Sn-P), Nickel Silver (Cu-Ni-Zn), and White Bronze (Cu-Ni); they were applied partly and wholly by the method of Laminatin, Reticulation, Fusing, and Electroforming skills. In case of C2200, the brass, the A. C. TIG welding method is better under 2mm slight plate; the D.C. TIG welding is better upper 2mm plate; and 250~300$^{\circ}C$ is recommended for remain heat treatment. In case of C5210, not having Hydrogen in high temperature return period, doesn't need Oxygen in high temperature and hardening in comparative high temperature neither, it is good for welding. It contains Sn 2-9% ad P 0.03-0.4% generally; and in accordance with the growth rate of Sn contain amount, the harden temperature boundary become broad. In case of cold moment after welding, they are recommended that higher speed TIG welding, smaller melting site and less than 200$^{\circ}C$ for pre-heating temperature. In case of C7701, the 10-20% Ni, 15-30% Zn are widely used.. If it is upper 30% Zn, it become (${\alpha}+{\beta}$) system and adhesive power rate become lower, and the productivity become lower in low temperature but the productivity become higher in high temperature. Nickel Silver's resistance of electricity is well; and the heatproof and incorrodibility is good, too. Lastly, in case of C8113, good at persistence in salty and grind; high in strength of high temperature. In case of white brass, contain 10-30% Nickel and hardened in high temperature and become single phrase. For these reason, the crystallization particles easily become large, if the resistance become higher small amount of Pb, P, S separation rate become higher.

• Proceedings of the KWS Conference
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• 2007.11a
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• pp.235-237
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• 2007

In this paper, fabrication of Sn-3.0Ag-0.5Cu solder bumping having accurate composition and behavior of intermetallic compounds(IMCs) growth at interface between Sn-Ag-Cu bumps and Cu substrate were studied. The ternary alloy of the Sn-3.0Ag-0.5Cu solder was made by two binary(Sn-Cu, Sn-Ag) electroplating on Cu pad. For the manufacturing of the micro-bumps, photo-lithography and reflow process were carried out. After reflow process, the micro-bumps were aged at $150^{\circ}C$ during 1 hr to 500 hrs to observe behavior of IMCs growth at interface. As a different of Cu contents(0.5 or 2wt%) at Sn-Cu layer, behavior of IMCs was estimated. The interface were observed by FE-SEM and TEM for estimating of their each IMCs volume ratio and crystallographic-structure, respectively. From the results, it was found that the thickness of $Cu_3Sn$ layer formed at Sn-2.0Cu was thinner than the thickness of that layer be formed Sn-0.5Cu. After aging treatment $Cu_3Sn$ was formed at Sn-0.5Cu layer far thinner.

• Journal of Korea Foundry Society
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• v.17 no.3
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• pp.245-251
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• 1997

Solderability, interfacial reaction and mechanical properties of joint between Sn-Bi-Ag base solder and Cu-substrate were studied. Solders were subjected to aging treatments to see the change of mechanical properties for up to 30 days at $100^{\circ}C$, and then also examined the changes of microstructure and morphology of interfacial compound. Sn-Bi-Ag base solder showed about double tensile strength comparing to Pb-Sn eutectic solder. Addition of 0.7wt%Al in the Sn-Bi-Ag alloy increase spread area on Cu substrate under R-flux and helps to reduce the growth of intermetallic compound during heat-treatment. According to the aging experiments of Cu/solder joint, interfacial intermetallic compound layer was exhibited a parabolic growth to aging time. The result of EDS, it is supposed that the soldered interfacial zone was composed of $Cu_6Sn_5$.

• Korean Journal of Heritage: History & Science
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• v.37
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• pp.267-284
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• 2004

As an initial step to understand the transitions in Korean bronze technology the present study has examined metallurgical microstructures of 8 artifacts excavated from the Silla Wang-Gyong site in Kyongju. Important trends have been found in alloy compositions and also in manufacturing processes. In the design of alloys, the Sn content was apparently changing toward the peritectic point, 22 mass %, of the Cu-Sn phase diagram while the Pb addition was intentionally avoided. This trend in composition was found accompanied by the introduction, subsequent to casting, of such special thermo-mechanical treatments as quenching and forging in artifact manufacture. In addition, the Sn content in alloys containing a significant amount of As was relatively low and no evidence of forging was observed in them. The use of quenching and forging and the rejection of Pb and As from alloys are all necessary requirements if the brittle nature of high Sn alloys is to be overcome in bronze working. This paper will show that the Wang-Gyong era corresponds to that of innovations leading to the technical climax in Korean bronze tradition, which has been maintained up to the present.

• Journal of Conservation Science
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• v.26 no.2
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• pp.157-169
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• 2010

This study focused on the material characteristics and archaeometric relationship between the molten glass and bronze materials within the crucibles and gilt-bronze Bodhisattva statue excavated from the Ssangbukri site in Buyeo, Korea. Yellowish green to red brown vitreous material in the crucibles was identified as lead glass which contained scarce amount of BaO, and low $Al_2O_3$ and CaO. Metallic molten material was identified as bronze of copper-tin-lead alloy with low amount of impurities that indicated well-refined materials. Also, cassiterite was used for raw metal ore of tin. The Bodhisattva statue consisted of major copper with trace impurities in the core metal, and gold amalgam in the gilded layer. Though lead isotopic analysis showed contradictory results in each lead glass, bronze and Bodhisattva statue that required further examination, it could be stated that the statue was made in the Ssangbukri site based on the high-level technical skills of bronze production.

• Journal of Conservation Science
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• v.20
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• pp.23-30
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• 2007

By analyzing the chemical compositions of bronze mirror presumably excavated from Mireuksaji temple site, Iksan, we have surveyed what alloy composition was used in casting the mirror, and also tried to estimate the manufacturing technique of the bronze mirror, through the observation of microstructure, as well as which region$^{\circ}{\emptyset}s$ galena the lead used in the mirror belonged to, by analyzing the ratio of the lead isotope. The content analysis result of bronze mirrors shows that it consists of 68.8 to 73.3wt% of Cu, 21.6 to 24.9wt% of Sn. In particular, the content of Pb of Mireuk 2 and 3 Samples are higher than those of Miruk 4. The observation result of microstructure demonstrates that Mireuk 2 and 3 consist of ${\alpha}$ and ${\alpha}+{\delta}$ eutectoide phase made through casting process. But Mireuk 4 show other process employed, such as quenching though martensite structure. In the analysis result of provenance though the lead isotope ratio, the origin of the used in bronze millers excavated from Mireuksaji temple site is presumed to be from galenas of Japen, like this those, the chemical competition, microstructure, and lead isotope ratio of bronze mirrors excavated from Mireuksaji can be utilized at fundamental data to compare mutually with other remains.

• Journal of Electrochemical Science and Technology
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• v.9 no.1
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• pp.37-43
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• 2018

In order to improve current efficiency and decrease energy consumption in the electrosynthesis of ammonium persulfate, electrolytic properties of four cation exchange membranes, namely, the $JCM-II^{(R)}$ membrane, $Nafion^{(R)}$ 324 membrane CMI-$7000^{(R)}$ membrane and a self-made perfluorosulfonic ion exchange membrane (PGN membrane) were investigated using a sintered platinized titanium anode and a Pb-Sb-Sn alloy cathode in a self-made electrolytic cell. The effect of cell voltage and electrolyte flow rate on the current efficiency and the energy consumption were investigated. The results indicated that the PGN membrane could improve current efficiency to 94.85% and decrease energy consumption to $1119kWh\;t^{-1}$ (energy consumption per ton of the ammonium persulfate generated) under the optimal operating conditions and the highest current efficiency of the $JCM-II^{(R)}$ membrane, $Nafion^{(R)}$ 324 membrane and CMI-$7000^{(R)}$ membrane were 80.73%, 77.76% and 73.22% with their lowest energy consumption of $1323kWh\;t^{-1}$, $1539kWh\;t^{-1}$ and $2256kWh\;t^{-1}$, respectively. The PGN membrane has the advantages of high current efficiency and energy power consumption and has sufficient mechanical strength with the reinforced mesh. Therefore the PGN membrane will has good value in popularization in the industrial electrosynthesis of ammonium persulfate in the future.