• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2539-2540
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• 1998

The characteristics of the electroplated nickel were investigated for the MEMS applications. Nickel sulfate bath was used and saccharine was added as the brightener. The effects of the brightener concentration were investigated by comparison of the surface morphology and the hardness of the electroplated nickel. The polarization characteristics were also investigated. The best results were obtained at 1g/$\ell$ saccharin addition.

• Journal of the Korean Electrochemical Society
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• v.9 no.4
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• pp.141-150
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• 2006

Nanocrystalline CoW thin/thick film alloys were electodeposited from citrate baths to investigate the influences of metal ion concentration, current density and solution pH on chemical composition, current efficiency, residual stress, surface morphology, and microstructure of the film. Deposit W (tungsten) content in CoW thin/thick film increased with increasing W ion concentration, current density, and solution pH in the plating bath. It was observed that residual stress in CoW thin/thick film decreased with increasing W ion concentration and solution pH. CoW thin film exhibited mixed phases of hop Co [(100) and (002)] and hcp $Co_3W$ [(002) and (201)] at W ion concentration with 0.02 to 0.08 M. The microstructure of CoW thin film at W ion concentration of 0.1 to 0.2 M was close to amorphous phase. The dominant phases were found to be hop Co (002) and hop $Co_3W$ [(200), (002) and (201)] at the current densities of 5, 10, 25, and $100mA{\cdot}cm^{-2}$ CoW thin film at the current densities of 50 and $75mA{\cdot}cm^{-2}$ was close to amorphous phase. At solution pH 8.7, CoW thin film exhibited hcp Co (002) and hop $Co_3W$ [(200), (002) and (201)]. Below solution pH 8.7, CoW thin film exhibited amorphous microstructure. The optimum electrodeposition conditions for CoW thin/thick film were found to be W ion concentration of 0.08 M, current density of $10mA{\cdot}cm^{-2}$, and solution pH 8.7.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.157-157
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• 2015

전기화학 성능이 우수하고 고내구성 고속 구리 전해도금용 DSE를 개발하기 위해 전기화학적 특성이 좋은 백금족 산화물의 조성비, 전처리 등의 공정으로 전극을 제조한 후, 고 전류밀도 조건에서 구리 전해도금을 실시하여 유기첨가제 소모율을 측정하여 최적의 전극제조 공정 조건을 확보하였다. 최적조건의 전극과 시제품 전극들을 비교분석한 결과, 상용 DSE와 비슷하거나 상회하는 내구수명을 가지는 것을 확인하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.11a
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• pp.59-60
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• 2007

열전재료는 냉각과 발전 분야에서 매우 매력적인 친환경 에너지 소재이다. 열전 재료의 효율을 나타내는 성능 지수는 ZT로 나타내는데, 기존의 bulk 재 열전소재의 경우 그 값이 1 내외이다. 그러나 기존의 타 기술과의 경쟁에서 우위를 점하기 위해서는 ZT 값이 3이 되어야 한다. 이론적인 계산에 의하면 나노 박막이나 나노와이어 형태로 열전재료를 제어를 함으로써 ZT 값의 현저한 향상이 예상되어 ZT값이 3이상의 값도 얻을 수 있을 것으로 기대된다. 전기도금법은 나노와이어 형태의 열전재료를 경제적으로 대량 생산할 수 있는 가장 유력한 방법이다. 본 발표에서는 전기도금법을 이용하여 n-형 BiTe 계와 p-형 BiSbTe계 열전반도체 나노와이어를 제조하고 그 특성을 측정한 연구결과를 소개한다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.05a
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• pp.157-158
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• 2015

$Ni-TiO_2$ 복합체를 전기도금법으로 제조할 때, pH, 전류밀도 변화에 따른 $TiO_2$ 부피분율을 측정하였다. 산화물의 부피분율은 pH가 높아질수록 낮아지고, 전류밀도가 증가하면, $100mA/cm^2$에서 최댓값을 가진 뒤에 감소하였다. 기존의 산화물 공석량 예측식 모델에 수소발생반응을 고려하여 적용한 결과, 기존 모델보다 실험값과 예측값의 정확도가 더 높았다. 따라서, 산화물이 전기도금층에 공석될 때에는 수소이온의 환원반응과 니켈이온의 환원반응을 종합적으로 고려하여야 한다.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.204-205
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• 2002

Co(P) 합금은 전기화학적으로 제조되는 강자성 재료 중 그 자기적 특성이 우수하여 이미 1960년대부터 연구가 진행되었으며$^{1)}$ 1980년대까지는 주로 무전해도금에 의해 제조되다가$^{2.3)}$ 1990년대 이후부터는 LIGA(Lithographie Galvanoformung Abformung) 공정이나 패터닝 공정과의 공정 통합의 용이성 때문에 전기도금방식이 주류를 이루고 있다.$^{4.5)}$ 그러나 전기도금에 의해 제조된 대부분의 Co(P) 합금은 P의 함량이 과다하여 비정질상태로 존재하며 추가적인 열처리 공정이 요구되고 자기적 성질도 좋지 못한 단점이 있었다. (중략)

• Resources Recycling
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• v.21 no.2
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• pp.41-46
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• 2012

An investigation on the recovery of nickel from spent electroless plating solutions has been performed using the electrowinning method. For this aim, nickel in spent electroless plating solutions was separated as nickel hydroxide through the addition of caustic soda. Nickel hydroxide was completely dissolved with sulfuric acid and an electrolysis was performed for electrowinning of nickel from nickel solutions. As a result, it was found that more than 99% of nickel in spent electroless plating solutions could be precipitated as nickel hydroxide above pH 10 with the addition of caustic soda. As far as the current efficiency in electrowinning of nickel was concerned, it was decreased with increase in the current density.

• Journal of the Korean Electrochemical Society
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• v.13 no.4
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• pp.270-276
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• 2010

Nickel-copper foam electrodes with pore gradient micro framework and nano-ramified wall have been prepared by using an electrochemical deposition process. Growth habit of nickel-copper co-deposits was quite different from that of pure nickel deposit. In particular, the ramified structure of the individual particles was getting clear with chloride ion content in the electrolyte. The ratio of nickel to copper in the deposits decreased with the distance away from the substrate and the more chloride ions in the electrolyte led to the more nickel content throughout the deposits. Compositional analysis for the cross section of a ramified branch, together with tactical selective copper etching, proved that the copper content increased with approaching central region of the cross section. Such a composition gradient actually disappeared after heat treatment. It is anticipated that the pore gradient nickel-copper nanostructured foams presented in this work might be a promising option for the high-performance electrode in functional electrochemical devices.

• 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.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.6
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• pp.590-596
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• 1999

The effects of additives on the Zn electrodeposition in chloride-based electrolyte were investigated using circulation cell with three electrodes system. The cathodic polarization increased with the addition of polyethylenglycol (hereafter PEG) in electrolyte. This was attributed to the adsorption of the additives on the electrode and the inhibition of migration of metal ion. The PEG, however, did not have any noticeable effect on the properties of plating solutions at the concentration used. The effect of PEG on the electrocrystallization was related to its molecular weight. With the increase of molecular weight, the cathodic polarization increased, while the surface roughness was improved with the decrease of brightness. Especially, the PEG mixed with different molecular weights was the most effective. The orientation and the type of the deposited grains were changed and refined by PEG, which resulted in the modification of deposited surface roughness and brightness.