• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2004년도 춘계총회 및 학술발표회
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• pp.24-24
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• 2004

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2004년도 춘계총회 및 학술발표회
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• pp.39-39
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• 2004

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2000년도 추계총회 및 학술발표회
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• pp.39-39
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• 2000

• 한국기계가공학회지
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• 제18권2호
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• pp.38-43
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• 2019

Electrochemical etching is a popular process to apply metal patterning in various industries. In this study, the electrochemical etching using a patterned copper layer was proposed to fabricate multilayered structures. The process consists of electrodeposition, laser patterning, and electrochemical etching, and a repetition of this process enables the production of multilayered structures. In the fabrication of a multilayered structure, an etch factor that reflects the etched depth and pattern size should be considered. Hence, the etch factor in the electrochemical etching process using the copper layer was calculated. After the repetition process of electrochemical etching using copper layers, the surface characteristics of the workpiece were analyzed by EDS analysis and surface profilometer. As a result, multilayered structures with various shapes were successfully fabricated via electrochemical etching using copper layers.

• Corrosion Science and Technology
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• 제9권6호
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• pp.331-337
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• 2010

This study compared the macro and micro electrochemical characteristics at the local area of welding metal on dissimilar welding parts for type 304 stainless steel (SS) and type 316L SS. The materials are used for double wall gas pipe of duel fuel engine for a ship. The various potentiodynamic experiments were performed several times in 10% ${H_2C_2O_2}{\cdot}{H_2O}$ solution using macro and micro methods, respectively. The micro electrochemical experiments conducted to resolve at local area on cross-section of dissimilar welding materials by micro-droplet cell device. The micro-droplet cell techniques can be used almost electrochemical experiments to resolve corrosion characteristics of the limited electrode area of the metallic surface between wetted spot of working electrode and tip of sharpened capillary tube. The results of macro electrochemical experiments show that resistance of active dissolution reaction at welding zone was high due to low current density by formation of passivation protection film at passive region. According to the micro electrochemical experiment, the corrosion current density of welding zone and bond zone were relatively high.

• Journal of Electrochemical Science and Technology
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• 제13권4호
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• pp.462-471
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• 2022

In this study, the electrochemical impedance characteristics of CO₂/H₂O co-reduction to produce CO/H₂ syngas were investigated in a low-temperature single cell. The effect of the operating conditions on the single-cell performance was evaluated at different feed concentrations and cell voltages, and the corresponding electrochemical impedance spectroscopy (EIS) data were collected and analyzed. The Nyquist plots exhibited two semicircles with separated characteristic frequencies of approximately 1 kHz and tens of Hz. The high-frequency semicircles, which depend only on the catholyte concentration, could be correlated to the charge transfer processes in competitive CO₂ reduction and hydrogen evolution reactions at the cathodes. The EIS characteristics of the CO₂/H₂O co-reduction single cell could be explained by the equivalent circuit suggested in this study. In this circuit, the cathodic mass transfer and anodic charge transfer processes are collectively represented by a parallel combination of resistance and a constant phase element to show low-frequency semicircles. Through nonlinear fitting using the equivalent circuit, the parameters for each electrochemical element, such as polarization resistances for high- and low-frequency processes, could be quantified as functions of feed concentration and cell voltage.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.1125-1128
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• 2002

Electrochemical capacitor made with metal oxide electrode uses rapid and reversible protonation/deprotonation of metal oxide material under the aqueous acidic solution, generally. Electrochemical stability window of aqueous electrolyte-type capacitor is narrow compared to that of organic electrolyte-type capacitor. Electrochemical characteristics of electrochemical capacitor made with metal oxide electrode and lithium cation based organic electrolyte were evaluated. Electrochemical capacitor based on $RuO_2$ electrode material and 1M $LiPF_6$ in mixed solvents of EC, DEC, and EMC has anodic and cathodic specific capacitance of 145 and 142 F/g-$RuO_2{\cdot}nH_2O$, respectively, by using cyclic voltammetry with scan rate of 2 mV/sec g-$RuO_2$ in potential range of 2.0~4.2V(Li|$Li^+$).

• Journal of Advanced Marine Engineering and Technology
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• 제38권9호
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• pp.1087-1093
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• 2014

Ti과 Nb과 같은 안정화 원소가 첨가된 스테인리스강은 입계부식 방지 효과가 있어 해양 및 조선 산업에 널리 사용되는 내식성 재료이다. 본 연구에서는 STS 304 주성분에 탄소 안정화 원소인 Ti(0.26%, 0.71%)와 Nb(0.29%, 0.46%, 0.71%)을 농도 변수로 첨가한 시편을 제작하여, 안정화 원소 함량에 따른 기계적 특성 및 전기화학적 특성을 평가하였다. 합금 원소 첨가에 따른 재료의 기계적 특성 파악을 위해 마이크로 비커스 경도기를 이용하여 경도 측정을 실시하였다. 재료의 전기화학적 특성을 파악하기 위해 타펠분석, 사이클릭 분극(Cyclic polarization) 실험, 정전류 실험을 실시하여 재료별 내식성을 상호 비교하였다. 실험 결과, Nb 첨가 시편의 경우 Nb 함량 증가에 따라 경도 향상을 나타냈으나, Ti의 경우 경도 향상 효과가 미미한 것으로 나타났다. 전기화학특성의 경우 Nb 함량 증가에 따라 대체적으로 전기화학적 특성이 개선되는 반면 Ti의 경우 오히려 전기화학특성이 열화되는 것으로 나타났다. 결과적으로, 안정화 원소의 종류와 함량에 따라 전기화학적 특성이 큰 차이를 나타내며, 해수환경에 적용되는 스테인리스강 강종 개발시 이를 고려한 설계가 중요할 것으로 사료된다.

• 한국수소및신에너지학회논문집
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• 제30권1호
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• pp.43-48
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• 2019

This study investigates the electrochemical characteristics of the hybrid cell that combined the advantageous characteristics of Li secondary battery and supercapacitor, high energy density and high power density, respectively. Electrochemical behaviors of the hybrid cell was characterized by charge/discharge, cycle and impedance tests. The hybrid cell using Li secondary battery and supercapacitor had better discharge capacity and cycle performance than that of using Li secondary battery only. Proper design of such a hybrid cell system is expected to result in substantial benefits to the well being of the Li secondary battery. The hybrid cell involving Li secondary battery for high energy density and supercapacitor for high power density may be the possible solution for future energy storage system.

• Corrosion Science and Technology
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• 제21권2호
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• pp.147-157
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• 2022

Electrochemical characteristics and damage behavior of 6061-T6 aluminum alloy used as a battery housing material for electric vehicles were investigated in solution simulating the acid rain environment with chloride concentrations. Potentiodynamic polarization test was performed to analyze electrochemical characteristics. Damage behavior was analyzed through Tafel analysis, measurement of damage area, weight loss, and surface observation. Results described that corrosion current density was increased rapidly when chloride concentration excceded 600 PPM, and it was increased about 7.7 times in the case of 1000 PPM compared with 0 PPM. Potentiodynamic polarization experiment revealed that corrosion damage area and mass loss of specimen increased with chloride concentrations. When chloride concentration was further increased, the corrosion damage area extended to the entire surface. To determine damage tendency of pitting corrosion according to chloride concentration, the ratio of damage depth to width was calculated. It was found that the damage tendency decreased with chloride concentrations. Thus, 6061-T6 aluminum alloy damage becomes larger in the width direction than in the depth direction when a small amount of chloride is contained in an acid rain environment.