• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.999-1002
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• 2002

In this research, the mechanism of micro-ECM was investigated with potentiodynamic method and the optimal condition for micro-ECM was selected by voltage-current-time curve with potentiostatic method. From the experimental result. it was confirmed that anodic voltage curve could be used very effectively for determining the optimal condition of micro-ECM, and the micro part which has extremely fine surface could be fabricated by use of micro-ECM with point electrode method.

• 마이크로전자및패키징학회지
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• 제30권3호
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• pp.51-55
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• 2023

강유전체 분극 이력곡선의 측정은 강유전체의 구조와 유전특성을 전반적으로 평가하고 해석하는 중요한 수단이다. 강유전체 시편에 저항성분이 포함될 경우 자발분극의 측정 값에 오차가 포함된다. 분극을 측정하는 전기적 회로를 구성할 때, 시편에 포함된 저항성분에 대응하는 외부 저항을 적절히 활용함으로서 시편의 저항성 손실에 의한 오차를 배제하고 내부에 유도된 강유전체 분극의 크기를 정확하게 측정할 수 있었다. 이와 같은 정확한 분극 이력곡선의 평가를 통하여 강유전체 내부의 이온의 변위 및 유전특성을 보다 정확하게 평가할 수 있을 것으로 기대된다.

• 한국해양공학회지
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• 제14권1호
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• pp.60-66
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• 2000

In order to study for corrosion behavior of reinforcing steel with oxidation layer. Experiments were done with various NaCl concentrations and with immersion time in simulated concrete pore solution(SPS) the characteristics of corrosion behavior were measured by polarization resistance method and cyclic potentiodynamic method. reinforcements were coated by epoxy except corrosion without oxidation layer and it also showed two anodic-nose. by the result of potention dynamic test the potential curve shift to low with time and anodic-nose was appeared with 3% NaCl solution after 15 days. By result of cyclic Potentiodynamic test the type of corrosion was different accoding to concentration.

• 대한기계학회논문집A
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• 제22권2호
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• pp.311-320
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• 1998

The cryogenic fracture behaviors of austenitic stainless steel HN2 developed for nuclear fusion reactor were evaluated quantitatively by using the small punch(SP) test. The electrochemical polarization test was applied to study thermal aging degradation of HN2 steel. The X-ray diffraction(XRD) analysis was conducted to detect carbides and nitrides precipitated on the grain boundary of the heat treated HN2 steel. The mechanical properties of the HN2 steel significantly decreased with increasing time and temperature of heat treatment or with decreasing testing temperature. The integrated charge(Q) obtained from electrochemical polarization test showed a good correlation with the SP energy(ESP) obtained by means of SP tests. From the results observed in the x-ray diffraction and anodic polarization curve, it was known that the material the grain boundary. Combining SP test and electrochemical polarization test, it could be useful tools to non-destructively evaluate the cryogenic fracture behaviors and the aging degradation for cryogenic structural material.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1893-1896
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• 2003

This research aimed to fabricate a micro structure using micro electrochemical machining (${\mu}$-ECM). with a view to that the theory of ${\mu}$-ECM is established accurately in a different way of conventional electrochemical machining. In details, if the impedance is existed in the system, it is difficult to analyze the micro electrochemical reaction efficiently in polarization curve using a potentiodynamic test. Hence, this research investigates the relationships between impedance and electric current measuring with a potentiostatic test applying to a pair or electrode as a constant potential. And this paper examines the influence of temperature of electrolyte on polarization curve for the quantitative analysis of electrochemical reactions.

• 동력기계공학회지
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• 제8권4호
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• pp.38-43
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• 2004

Thermal spraying onto the metal substrate has been widely used as a technique of the surface treatment in the various industrial field. A wide range of thermal spray technologies exist and all rely on the fundamental process of fusing a metal feedstock, atomizing it and transporting it to the surface of a substrate. Specially, these methods have been taken into account as the protection method against the corrosion. In this study, the polarization characteristics were carried out on the thermal sprayed coating layer immersed in various pH of diluted aqueous solutions at $25^{\circ}C$. Aluminum, Zinc, Ni-base alloy, alumina and polyethylene powder were used with sprayed coating materials. From the polarization curves, the electrochemical corrosion potential($E_{corr}$) and the corrosion current density($I_{corr}$) were investigated.

• Journal of Advanced Marine Engineering and Technology
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• 제41권3호
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• pp.230-237
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• 2017

본 연구에서는 해상풍력 타워 지지구조물용 강재인 S355ML 강에 대하여 전기화학적 기법으로 전기방식 설계에 필요한 최적 방식전위를 규명하고자 하였다. 동전위분극 실험 결과, 양극분극 곡선 상에서는 부동태 구간은 존재하지 않으며, 음극분극 곡선 상에는 용존산소환원반응에 의한 농도분극 구간과 수소가스 발생에 의한 활성화분극 구간이 관찰되었다. 음극방식 시 방식전위에 해당하는 농도분극 구간은 약 - 0.72 V ~ - 1.0 V의 전위 구간인 것으로 확인되었다. 다양한 전위에서 정전위 실험을 실시한 결과 전류밀도 변화는 시간에 따라 안정화되는 경향을 나타냈다. 1200초 동안 정전위 실험 후 주사전자현미경과 3D 분석 현미경을 이용한 시험편 표면 분석 결과, 양극분극 전위에 해당하는 0 V ~ - 0.50 V의 전위구간에서는 양극용해반응에 의한 부식손상이 관찰되었다. 이에 반해 음극분극 전위 영역에서는 대체적으로 손상이 없는 양호한 표면을 유지하였으며 석회질 피막 형성을 확인할 수 있었다. 연구결과, 농도분극 영역에 해당하는 - 0.8 V ~ - 1.0 V의 전위영역이 S355ML 강의 외부전원법에 의한 음극방식 적용 시 최적 방식 전위 구간으로 사료된다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.74.1-74.1
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• 2010

수치해석을 이용하여 형상 및 운전 조건에 따른 금속공기전지의 전기화학적 성능 변화를 조사하였다. 저전류밀도 영역에서의 전지 성능은 농도손실에 의한 영향이 미미하므로 활성화 손실과 저항손실만을 고려한 수치해서 모델을 적용하였다. 지배방정식은 전기전도식을 이용하였으며 전극 표면의 활성화손실을 모사하기위해 아연극(음극)에는 butler-volmer식을, 공기극(양극)에는 tafel식을 적용하였다. 실험결과와의 비교/분석을 통하여 수치해석 모델의 타당성을 검증하였다. 또한, 아연극과 공기극 사이의 간격과 전해질 농도 변화에 따른 아연공기전지 내부에서의 전류밀도분포를 조사하였으며, 분극곡선을 통해 전기화학적 성능을 평가하였다.

• 한국해양공학회지
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• 제17권3호
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• pp.39-45
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• 2003

Shot peening is an effective method of improving the fatigue strength of components and structures. The compressive residual stress produced by surface plastic deformation with shot peening is usually regarded as the major factor in increasing fatigue strength. In this study, the influence of shot peening on corrosion was investigated. Spring steel immersed in $3.5\%$ NaCl prior was used to evaluate the effect of shot peening on fatigue properties. The immersion test was performed on the five kinds of specimens with shot peened and unpeened. The distributions of residual stresses of shot peened spring steels were measured in an X-ray diffraction apparatus, using the two-point method. Corrosion potential, polarization curve, residual stress, etc. were investigated, based on the experimental results. From test results, the effect of shot peening on the corrosion was evaluated.

• Journal of Advanced Marine Engineering and Technology
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• 제23권5호
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• pp.695-701
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• 1999

Thermal sprayed Ni-Cr alloy coating on the carbon steel was carried out erosion-corrosion test and electrochemical corrosion test in the marine environment. THe erosion-corrosion behavior and electrochemical corrosion characteristics of substrate(SS400) and thermal sprayed Ni-Cr coating was investigated, The erosion-corrosion control efficiency of Ni-Cr coating to substrate was also estimated quantitatively.