• Carbon letters
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• 제2권1호
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• pp.15-21
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• 2001

In this work, activated carbon fibers (ACFs) were plated with copper metal using electroless plating method and the effects of surface properties and pore structures on chromium adsorption properties were investigated. Surface properties of ACFs have been characterized using pH and acid/base values. BET data with $N_2$ adsorption were used to obtain the structural parameters of ACFs. The electroless copper plating did significantly lead to a decrease in the surface acidity or to an increase in the surface basicity of ACFs. However, all of the samples possessed a well-developed micropore. The adsorption capacity of Cr(III) for the electroless Cu-plated ACFs was higher than that of the as-received, whereas the adsorption capacity of Cr(VI) for the former was lower than that of the latter. The adsorption rate constants ($K_1$, $K_2$, and $K_3$) were also evaluated from chromium adsorption isotherms. It was found that $K_1$ constant for Cr(III) adsorption depended largely on surface basicity. The increase of Cr(III) adsorption and the decrease of Cr(VI) adsorption were attributed to the formation of metal oxides on ACFs, resulting in increasing the surface basicity.

• 한국표면공학회지
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• 제23권3호
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• pp.173-182
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• 1990

In order to prevent the thermal and enviromenatal degradation of contact materials a nickel layer was plated as an undercoat of gold plating on the surface phosphorous bronze. The thickness of nikel and gold coating and chemical resistance of the coatings were measured at various conditions. Variation of morphology and chemical composition was studied by SEM, EDS and ESCA, respectively. Nickel layer was found to act as a thermal diffusion barrier and to retard the diffusion of copper from substrate to gold coating in the temperature $200^{\circ}C$~$400^{\circ}C$. below $200^{\circ}C$gold coated contacts showed a stable and low contanct resistance, while above $200^{\circ}C$ rapid diffusion of copper formed copper oxide on the surface layer and raised the contact resistance. With the nickel thinkness of abount 5$\mu$m as an undercoat the gold thinkness of $0.5\mu$m, showed satistactory (less than 1 m$\Omega$) contact resistance below 20$0^{\circ}C$ and corresponding gold thinkness increased to 1.0 m at $300^{\circ}C$~$400^{\circ}C$.

• 한국표면공학회지
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• 제49권5호
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• pp.401-407
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• 2016

In this work, effect of zincate treatment of AZ91 Mg alloy on the following electrodeposition of copper was examined in a non-cyanide bath containing pyrophosphate ions in view of surface morphology and adhesion of the electrodeposited copper layer. Without zincate treatment, the electrodeposited copper layer showed very porous structure and poor adhesion. On the other hand, the copper layer electrodeposited on the zincate-treated surface showed dense structure and good adhesion. The dissolution rate of AZ91 Mg alloy after the zincate treatment appeared to decrease about 40 times in the copper pyrophosphate bath, as compared to that of the surface without zincate treatment. The porous morphology and poor adhesion of a copper layer on the AZ91 Mg alloy surface without zincate treatment were attributed to small number of nucleation sites of copper because of rapid dissolution of the magnesium substrate in the pyrophosphate bath. Based on the experimental results, it is concluded that the zincate treatment to form a conducting and protecting layer on the AZ91 Mg alloy surface is essential for successful electrodeposition of a copper layer on AZ91 Mg alloy with good adhesion and dense structure in the copper pyrophosphate bath.

• 한국분말재료학회지
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• 제15권3호
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• pp.221-226
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• 2008

Silver coated copper composite powders were prepared by electroless plating method by controlling the activation and deposition process variables such as feeding rate of silver ions solution, concentration of reductant and molar ratio of activation solution $(NH_4OH/(NH_4)_2SO_4)$ at room temperature. The characteristics of the product were verified by using a scanning electron microscopy (SEM), X-ray diffraction (XRD) and atomic absorption (A.A.). It is noted that completely cleansing the copper oxide layers and protecting the copper particles surface from hydrolysis were important to obtain high quality Ag-Cu composite powders. The optimum conditions of Ag-Cu composite powder synthesis were $NH_4OH/(NH_4)_2SO_4$ molar ratio 4, concentration of reductant 15g/l and feeding rate of silver ions solution 2 ml/min.

• 공업화학
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• 제23권6호
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• pp.554-560
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• 2012

전자 통신 산업이 발달하면서 도전성 재료의 사용이 증가하게 되었다. 그에 따라 주로 사용되어오던 귀금속들을 대신할 저렴한 재료들이 필요하게 되었다. 그 중 구리는 귀금속에 비해 값이 저렴하고, 유사한 열 전기적 특성을 가졌지만 대기 중에서 쉽게 산화가 되는 문제점이 있다. 산화를 방지하기 위해서는 제조공정이 복잡해져 사용에 제한이 되어왔다. 구리의 산화 방지를 위한 방법 중 하나로 산화에 강한 금속을 Core-Shell 구조로 도금시켜 고유의 특성을 유지하며 산화를 방지하는 방법이 있다. 본 연구에서는 무전해 도금법으로 구리분말에 주석(Sn) 도금을 했고, 도금에 영향을 주는 인자들에 대해서 연구했다. XRD, FE-SEM, FIB, 4-Point Probe 등의 분석결과 구리 표면에 치밀한 주석피막이 도금되었고, 대기 중에서 산화가 되지 않았다. 분석결과를 바탕으로 최적의 도금 조건을 도출했고, 추가적으로, 도전성 필러 응용 가능성에 대한 실험을 했다. 합성된 분말을 pellet 형태로 압분 성형한 후 저온 열처리 전과 후의 변화를 분석했다. 그 결과 저온 치밀화를 통해 용융된 주석이 구리 입자들을 상호연결 시켰고, 전기 전도가 향상되었다.

• 마이크로전자및패키징학회지
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• 제22권4호
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• pp.99-104
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• 2015

비아 필링에 있어서 void나 seam 생성이 없이 비아를 채우는 것은 매우 중요한 사항으로 전류밀도, 전류모드, 첨가제 등을 변화시켜 결함없는 비아를 얻어왔다. 그러나 다양한 첨가제의 부산물이 오염의 원인이 되며 도금액의 수명을 줄이는 문제점이 있었다. 본 연구에서는 오염을 최소화하기 위하여 다른 첨가제가 없이 JGB만을 사용하여 JGB 농도와 전류밀도 변화에 따른 비아 필링 현상을 연구하였다. 지름이 $15{\mu}m$이며 종횡비 4인 비아가 사용되었으며 펄스전류를 이용하여 도금을 하였다. 전류밀도는 $10{\sim}20mA/cm^2$, JGB 농도는 0~25 ppm까지 변화시키면서 JGB 농도와 전류밀도와 의 상관관계를 mapping 하였다. 그로부터 지름이 $15{\mu}m$이며 종횡비 4인 비아 필링의 최적 조건을 확립하였다.

• 한국표면공학회지
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• 제55권4호
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• pp.222-230
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• 2022

The electroplating for copper foils has many advantages in economics. During the electroplating, the selection of appropriate additives is needed to manufacture copper foils with various properties. Therefore, it is investigated the initial plating voltage and the properties of copper foil electroplated in the electrolyte with benzothiazole as additives. The addition of benzothiazole without any additives decreased effectively the initial plating voltage. However, the initial voltage increased when the additives was used in combination with an inhibitor and a leveler along with benzothiazole. Moreover, the voltage tends to increase with the concentration of benzothiazole except for 40 ppm group. The mixed additives could change not only the initial voltage but also the morphology of crystals on the surface. When benzothiazole is added at 20 ppm or less, it was observed that the clustered crystals existed on the surface, which result in ununiform surface and high roughness value. In addition, the grain size increased with the amount of benzothiazole, but the resistivity decreased. However, when the leveler was added in 20 ppm, the grain size was decreased with the amount of benzothiazole. The size of the crystals could be influenced by the mixing ratio of additives. Therefore, it is necessary to study on the effect of concentration ratio of additives in the future.

• 마이크로전자및패키징학회지
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• 제28권1호
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• pp.55-60
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• 2021

유연한 특성을 유지하면서 높은 접착력을 가진 웨어러블 디스플레이를 제작하기 위하여 전해도금법을 이용한 접착법을 진행하였다. 또한 섬유에 접착된 LED의 사파이어 기판을 제거하기 위하여 LLO 전사법을 이용하였다. 그 후 전해도금을 이용한 접착법을 진행한 샘플의 SEM, EDS 데이터를 통하여 실제로 구리가 섬유직물의 격자사이를 관통하여 성장하며 광원과 섬유를 고정시켜주는 것을 확인하였다. 구리의 접착특성을 확인하기 위하여 Universal testing machine (UTM)을 이용하여 측정하였다. 도금 접착 후 laser lift-off (LLO) 전사공정을 완료한 샘플과 전사공정을 진행하지 않은 LED의 특성을 probe station을 이용하여 비교하였다. 공정 이후의 광원의 특성을 확인하기 위하여 인가 전류에 따른 electroluminescence (EL)을 측정하였다. 전류가 증가할수록 온도가 상승하여 Bandgap이 감소하기 때문에 spectrum이 천이하는 것을 확인하였다. 또한 radius 변화에 따른 샘플의 전기적 특성 변화를 probe station을 이용하여 확인하였다. Radius 변형에도 구리가 bending stress를 견딜 수 있는 기계적 강도를 가지고 있어 Vf 변화는 6% 이하로 측정되었다. 이러한 결과를 토대로 웨어러블 디스플레이 뿐만 아니라 유연성이 필요한 배터리, 촉매, 태양전지 등에 적용되어 웨어러블 디바이스의 발전에 기여할 수 있을 것으로 기대한다.

• 한국태양에너지학회 논문집
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• 제33권3호
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• pp.27-35
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• 2013

One of the most important factors that have a large influence on performance of the solar water heater system is performance of the solar collector, more detailedly, coating technology on the surface of the solar collector, which can provide high solar absorptance and low emittance. The core of the coating technology is to coat solar selective surfaces. In this study, various performance experiments are carried out using $Cr_2(SO_4)_3{\cdot}15H_2O$ coating technology. Here, IGBT(Insulated Gate Bipolar Transistor) of 5000A-15V was used as the surface processing rectifier which can stably output power and also can control voltage and current. The plating solution mainly contains black chrome$^{+3}$ concentration, H-y Conductivity, N-u Complex, NF Additive and NC-2 Wetter. Before applying the black chrome coating on the copper plate, optimal conditions are provided by using various preprocessing methods such as removal of fat, activation, electrolytic polishing, nickel strike, copper sulfate plating and bright neckel plating, and then the automatic continuous coating experiment are performed according to plating time and cathode current density. In the experiment, after the removal of fat, chemical polishing, nickel strike and activation processes as the preprocessing methods, the black chrome coating was performed in a plate solution temperature of $28^{\circ}C$ and a cathode current density of $18A/cm^2$ for 90 seconds. The thickness of chrome and nickel on the coated plate is $0.389{\mu}m$, $159{\mu}m$ respectively. As a result of the coating experiment, it showed the most excellent performance having a high solar absorptance of 98% and a low emittance of $5{\pm}1%$ when the black chrome surface had a thickness of $0.398{\mu}m$.

• Membrane and Water Treatment
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• 제11권3호
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• pp.179-187
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• 2020

Electrodialysis has been applied for treatment of industrial wastewater including metal electroplating. The wastewater from metal plating industries contains high concentrations of inorganics such as copper, nickel, and sodium. The ions in the feed were separated due to the electrical forces in the electrodialysis. The concentrate compartment is exposed to the elevated concentrations of the ions and yielded inorganic precipitations on the cation exchange membranes. The presence of organic matter in the metal plating wastewater affects complex interfacial reactions, which determines characteristics of inorganic scale fouling. The wastewater from a metal plating industry in practice was collected and the inorganic and organic compositions of the wastewater were analyzed. The performance of electrodialysis of the raw wastewater was evaluated and the effects of adjusting pH of the raw water were also measured. The integrated processes with neutralization and electrodialysis showed great removal of heavy metals sufficient to discharge to aquatic ecosystem. The organic matter in the raw water was also reduced by the neutralization, which might enhance removal performance and alleviate organic fouling in the integrated system.