• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.98.2-98.2
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• 2018

현재 시중에 판매되는 대부분의 중성 주석 도금액의 경우 pH 사용 구간이 3~5 정도를 형성하고 있으며, 이보다 높을 경우 도금간 칩붙음 및 주석의 4가로의 산화가 빠르게 일어나는 문제점을 가지고 있다. 또한 낮은 pH로 인해 내산성이 취약한 소재의 경우 도금이 불가능할 정도의 소재상 damage를 확인할 수 있으며, 이는 제품 소재 선택에 제약이 따름으로 인해 산업의 발전을 저해하는 요소임이 분명하다. 이를 극복하기 위해 종래의 도금액에 1종 이상의 첨가제를 첨가하여 소재의 damage를 최소화하는 방안을 사용 중이지만 이러한 방법으로는 궁극적으로 문제를 해결하는 데에는 한계가 있다. 따라서 본 연구에서는 완전한 중성(pH6~7)을 가지는 도금액을 개발함으로써 도금제품의 소재 선택에 자유를 부여함과 동시에 친환경 원료를 사용함으로써 폐수처리의 용이함과 생산 현장의 환경 개선에 그 목적이 있다.

• Journal of the Korean institute of surface engineering
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• v.4 no.1
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• pp.16-23
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• 1971

In this study , fluoborte solution consisting of lead fluoborate, tin fluoborate and cupric acetate was used. By addition of small amount of Cu+= ion to the solution, the Cu content of deposition layer was almost controlled less than 5%. The amount of Cu in deposition layer was almost constant without any influence of Pb++ & Sn++ in the solution, and the amount of Pb was increased by the increase of total concentration of Pb++ +Sn++ in the solution, and the amount of Pb was increased by the increase of total concentration of Pb++ +Sn++ in the solution . Agitation of plating solution & low current density result in the increase of Cu content. Analyzing of microscopic structures and etching tests of the deposited alloy, it was believed that the alloy had a lamellar structure consisting of copper rich lamellar and lead rich layer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.80-87
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• 2018

In recent years, due to the spread of various renewable energy power sources and the pursuit of high efficiency and low-power consumption, not only trends in the electric power industry but also the consumption, control methods, and characteristics are diversified. However, in this diversified electric power industry, the fuse (which is the core part responsible for safety) has not developed significantly in classical operation mode, and thus, fires continue to occur. In this paper, the effects of low melting-point metal plating and high melting-point metal plating on operating characteristics and IT curve movement of the fuse are investigated in a cartridge fuse, which is a classic fuse manufacturing method. The effects of plating on the thickness of the fuse are investigated, and various operating characteristics of the fuse are implemented. In addition, it is suggested that the plating of the low melting-point metal moves the rated current line of the fuse to a low rating, and moves operating characteristics to characteristics of delay operation. It is possible to design various operating characteristics using this characteristic.

• Journal of the Korean institute of surface engineering
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• v.40 no.6
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• pp.254-257
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• 2007

TiN coating on tool steel has been widely used for the improvement of durability of tools. In this work, radical nitriding(RN) is carried out on SKD61 at $450^{\circ}C$ for 5 hours in the ammonia gas pressure $2.7{\times}10^3\;Pa$. The TiN coating is carried out by arc ion plating(AIP) with the process parameters: arc power 150 A, bias voltage -50V, coating time 40 minutes and nitrogen gas pressure $4{\times}10^3\;Pa$. Hardness, elastic modulus, friction coefficient and adhesion of TiN coating on substrates of both TiN/SKD61 and TiN/RN SKD61 coatings are investigated comparatively. The primary crystalline faces of TiN surface are(200) and(111) for TiN/SKD61 and TiN/RN SKD61 respectively. In addition to the primary phase, Fe phase exists in TiN/SKD61 coating, but not in TIN/RN SKD61. The hardness of TiN/RN SKD61 is about 700 Hv, 250 Hv(56%) higher than that of TiN/SKD61 at the near interface of TiN and substrates. At the TiN surface, hardness of TiN/RN SKD61 is 2,149 Hv, 71 Hv(3%) higher than that of TiN/SKD61. The elastic modulus of TiN coating is improved to 26.7 GPa(6%) by radical nitriding. The adhesion is improved by the RN coating showing no spalling. buckling and chipping on the scratch test track which are shown on the non-RN TiN/SKD61.

• Journal of Conservation Science
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• v.31 no.3
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• pp.309-318
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• 2015

The staff given with chair to Yi Gyeong-seok, senior official over 70 years old by King Hyeonjong of Joseon Dynasty is representative handcraft of Joseon Dynasty. Results of analysis on the metallic decoration show that the metallic ornament of the end part which is connected to the spade was made by rolling of iron plate and brass plating. The plated part is limited to the ornament of the end part connected to the spade and the plating was not applied to the spade. Brass including 20% zinc was used for the connecting part of guard while brass gilded iron was used for the spade. This suggests that the tone of the connecting part of the guard and the spade was not different for reason of visual harmonization. Potential applied plating method can be amalgam, dippping in molten brass, and brushing but the analysis result suggests that dipping in molten brass method is the most likely accepted method. The brass guard of knife was joined by tin-lead solder. Rivet used to fix the blade was made by pure iron as an optimum material which satisfies flexibility and strength.

• Conservation Science in Museum
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• v.23
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• pp.1-16
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• 2020

In this paper, Gilt-bronze Standing Avaolkiteshvara (National Treasure No. 293, M355) excavated at Gyuam-ri in Buyeo was observed with a microscope to identify the production technique applied to it. It was also analyzed with XRF and hard X-ray to identify the composition and the surface treatment techniques and casting method applied. In this statue, Avalokiteshvara is standing upright on a lotus pedestal. The lotus designs on the pedestal and those on the shawl flowing down on both sides of the statue are characteristic of Buddhist statues from the seventh century or later. The use of supports to affix the outer and inner molds and traces of injected cast were observed in the interior of the pedestal. The blisters on the arms and pedestal created during the bronze casting indicate the use of lost-wax casting, which was popularly employed for the production of mid- or small-sized gilt-bronze Buddhist statues in ancient times. The composition analysis identified a copper-tin-lead ternary alloy in the interior of the statue that was conventional used in the sixth and seventh centuries. It is likely that this simple alloy was used to facilitate casting and produce clearer expressions of designs and ornaments on the statue. Mercury (Hg) was detected on the surface of the statue, indicating the use of amalgam-plating with gold (Au) dissolved in mercury. This plating method is a common surface treatment technique used for small gilt-bronze statutes in ancient Korea.

• Transactions on Electrical and Electronic Materials
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• v.15 no.2
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• pp.91-95
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• 2014

This paper presents the structure and process technology of simple and low-cost wafer-level packaging (WLP) for thin film radio frequency (RF) devices. Low-cost practical micromachining processes were proposed as an alternative to high-cost processes, such as silicon deep reactive ion etching (DRIE) or electro-plating, in order to reduce the fabrication cost. Gold (Au)/Tin (Sn) alloy was utilized as the solder material for bonding and hermetic sealing. The small size fabricated WLP of $1.04{\times}1.04{\times}0.4mm^3$ had an average shear strength of 10.425 $kg/mm^2$, and the leakage rate of all chips was lower than $1.2{\times}10^{-5}$ atm.cc/sec. These results met Military Standards 883F (MIL-STD-883F). As the newly proposed WLP structure is simple, and its process technology is inexpensive, the fabricated WLP is a good candidate for thin film type RF devices.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.3
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• pp.201-207
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• 2020

With the expansion in the use of DC power systems and increased need for system maintenance, the development of measurement devices for maintenance requires high stability. Of the different kinds of DC current measurement devices, the single-shot measurement device causes the input signal of the current measuring unit to initially generate a high inrush current. The high inrush current flows into the signal processor of the meter, shortening the life of the internal fuses and causing failure. Therefore, in this study, the I²t value for increasing the durability of the fuse is designed using the available wire diameter. Operating characteristics for 210~400% over-current of the rated current, which is relatively low over-current, are realized by the plating of low melting tin metal. As a result, a method of designing a fuse element for a DC power supply, which improves the safety of the DC current measurement device by blocking the failure caused by the inrush current, is presented.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.112-112
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• 2016

인체접촉시 니켈도금의 알러지 반응을 억제하기 위한 대체 도금기술인 비 시안계 Cu-Sn 합금도금을 개발함에 있어서, 황산구리5수화물과 황산제일주석을 금속염으로 하여 황산 및 계면활성제, 유화제 등을 포함한 각종 유기첨가제를 포함하였고 특히 은백색조의 외관 색상과 안정적인 Cu-Sn 합금전착을 위해 2종의 착화제인 EDTP($C_{14}H_{32}N_2O_4$)와 TEA(Triethanolamine)를 첨가한 비 시안계 Cu-Sn 합금 도금액을 도출하였다. Cu-Sn 합금도금 피막 조성의 균일화를 도모하기 위해서는 합금 도금액중의 Cu와 Sn 금속이온 농도를 일정하게 유지하는 것이 필요하다. 그러나 합금 도금액중 2가 주석이온($Sn^{2+}$)은 수용액중에서 4가 주석이온($Sn^{4+}$)으로 산화됨으로써 도금액 색상이 백탁이 되고 Stannic Hydroxide($Sn(OH)_4$, $SnO_2{\cdot}2H_2O$)이 생성되어 대량의 침전물이 침강하는 문제점이 발생되는 등 시간 경과에 따른 도금액의 경시 변화가 발생되었다. 상기 침전물은 연속여과에 의해 제거 가능하나 합금 도금액중 $Sn^{2+}$ 농도가 지속적으로 감소하게 된다. 이는 합금 도금액중 금속이온 비율이 변동함으로써 합금도금 피막의 조성비를 일정하게 유지하는 것이 곤란해진다. 이에 $Sn^{4+}$ 침전물 생성을 방지하기 위한 산화방지제를 개발하고 또한 산화방지제의 첨가에 따른 도금 피막 외관에 미치는 영향을 평가하여 외관 개선을 위한 광택제를 개발하고자 한다. 본 연구의 결과를 토대로 니켈도금과 동등 이상의 기능 특성을 갖는 비시안계 Cu-Sn 합금도금액을 개발하여 실용화하는 것을 목적으로 하였다.

• Applied Chemistry for Engineering
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• v.22 no.1
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• pp.98-103
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• 2011

We prepared a counter electrode by electroplating Ni as underlayer and Pt as plating layer on the FTO glass to increase the efficiency of dye-sensitized solar cell (DSSC). We found an excellent adhesion between Ni underlayer and FTO glass when Ni underlayer was electroplated at $10mA/cm^2$ for 2 min on FTO glass. We observed Ni and Pt metal diffraction peaks by XRD analysis when Ni underlayer was electroplated at $10mA/cm^2$ for 2 min, and Pt layer was electroplated at $5mA/cm^2$ for 1 min on the Ni underlayer. Photovoltaic performance and impedance analysis of DSSCs fabricated with this counter electrode shows the highest efficiency of 5.6% and the lowest resistance of 75 ohm.