• 자원리싸이클링
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• 제18권4호
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• pp.44-51
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• 2009

양극과 철근과의 사이에 이온의 흐름이 원활하도록 전도성이 우수한 탄소리본전극과 표면코팅을 실기한 후 무공해, 반영구적인 무한태양전기를 전류로 공급한 전기방식에 의한 콘크리트 중의 철근 부식 방지 효과를 알아보기 위하여 복극량, 철근의 복극전위 및 부식속도를 측정하였다. 실험결과 방식을 실시한 모든 대상 시험체가 NACE의 복극량 기준 100 mV 기준을 만족하였으며, 방식을 실시한 경우 복극전위와 부식속도가 안정적인 범위에 있음을 알 수 있었다.

• 한국가스학회:학술대회논문집
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• 한국가스학회 2003년도 추계학술발표회 논문집
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• pp.183-187
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• 2003

• 한국가스학회:학술대회논문집
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• 한국가스학회 2003년도 추계학술발표회 논문집
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• pp.59-64
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• 2003

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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• pp.197-202
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• 1997

Recently the interest in the reinforcing steel corrosion due to the use of sea-sand and deicing salt, marine environment, and carbonation in RC structures is increasing, therefore the studies on the corrosion control of reinforcing steel in concrete are vigorously proceeding. In this study, from the viewpoint of electrochemical process of steel corrosion in concrete we applied the impressed current system among the cathodic protections to reinforcing steel in concrete and ascertained the protection effect by half-cell potential, corrosion rate, and depolarization.

• Journal of Advanced Marine Engineering and Technology
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• 제13권2호
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• pp.43-63
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• 1989

Various kinds of corrosion prevention methods have been developed. It is known that the method of electrochemical protection is more effective and economical than any other method on the large scale metal structures in corrosive solutions. Strong acid solutions such as nitric and sulfuric acid solutions are often used in industries, and the expensive stainless steel is almost exclusively used for the equipment that comes in contact with such acid solutions. However, it is more reasonable that carbon steel is used rather than stainless steel depending upon concentration of those acid solutions from the economical viewpoint. In this study, the typical strong acid solution such as nitric and sulfuric acid solutions are chosen for the experiment and the selected materials of specimen are the stainless steels of SUS 304L and SUS 316L, the carbon steels of SS 41, SM 50 and RA 32, and highly pure lead. Electrochemical protection diagrams can be drawn with data from the external cathodic and anodic polarization curves of SUS 304L, SUS 316L and SM 50 steels in 5-60% nitric acid solutions and from those polarization curves of SS 41, RA 32, SM 50 and SUS 316L steels, and highly pure lead in 2.5-98% sulfuric acid solutions at the slow scanning rate. The data obtained with using the determination method of the optimum cathodic protection potential, the Tafel extrapolation method and the characteristics of anodic polarization curves. The main results obtained from the diagrams are as follows: 1) In nitric acid solution : (1) Corrosion potentials exist in each of those corrosion zones on the stainless steels in the lower concentration than about 12% solutions and on the high tensile strength steels in the lower concentration than about 30% solutions, but the corrosion current (density) in each zone is small on the above mentioned former steels and large on the latter ones. (2) The stainless steels can be self-passivated in the higher concentration than 15% solutions, and the high tensile strength steels gives rise to the same phenomenon in the higher concentration than 35% solutions. (3) The stainless steels in the lower concentration than 60% solutions and the high tensile strength steels in the higher concentration than 35% solutions can be used without protection, but the latter steels must ve protected anodically in the lower conccentration than about 30% solutions. 2) In sufuric acid solution : (1) The carbon steels can be self-passivated in the higher concentration than 45% solutions, and the SUS 316L steel in higher concentration than 75% solutions and the lead in all concentration solutions also gives rise to the same phenomenon. (2) The lead in the lower concentration than 80% solutions and the SUS 316L steel in the higher concentration than 80% solutions can be used without protection. (3) The carbon steels in the higher concentration than 50% solutions also can be used without protecting economically, but the SUS 316L steel in the 20-70% solutions are considerably corrosive without protecting anodically.

• 대한기계학회논문집A
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• 제26권5호
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• pp.896-903
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• 2002

The susceptibility of SCC for the weldment and PWHT specimens of HT-60 steel was evaluated using a slow strain rate method under applied potential by means of the potentiostat in synthetic seawater. In case of the parent, anodic polarization voltage was inappropriate in elongating the time to failure(TTF). -0.8V corresponding to cathodic protection range is most effective in improving the SCC resistance against corrosive environment. In case of the weldment, the values of reduction of area(ROA) and TTF at -0.68V corresponding to cathodic polarization value were 45.2% and 715,809sec which were the largest and longest life among other applied potentials. Those were vise versa at -1.1V. In case of the PWHT specimens, TTF and ROA at -0.68V was longest and largest like the weldment. Besides, PWHT is effective in prolonging the time to failure of the welded off-shore structure due to softening of effect. Regardless of the weldment and PWHT specimen, as corrosion rate gets higher, TTF becomes shorter and deformation behaviour for the weldment and PWHT specimen at -1.1V was shown to be irregular. Finally, it was found that specimens showed brittle fracture at -1.1V, but more ductile fracture accompanying the micro-cracks at applied potential of -0.68V.

• 한국표면공학회지
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• 제40권6호
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• pp.262-270
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• 2007

Recently, there has been a new appreciation of aluminum alloys as materials that are capable of reducing the environment load. This is because aluminum alloys are lightweight, easy to recycle, permit miniaturization, and have environmental friendly properties. In this study, we investigated the mechanical and electrochemical properties of 5083F aluminum alloys using slow strain rate test(SSRT) and potentiostatic tests under various potential conditions. In the potentiostatic tests, the current density in the potential range from -0.7 to -1.4V after 1,200 s was low. After considering the results of the potentiostatic tests, maximum tensile strength, yield strength, elongation, time-to-fracture, observation of fractured specimen and fractography analysis, the optimum protection potential range was between -1.3 and -0.7V(Ag/AgCl).

• Journal of Electrochemical Science and Technology
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• 제10권2호
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• pp.148-158
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• 2019

The corrosion protection of AA2024 PPy coated samples doping with nanosized metal oxides, including $TiO_2$ and $CeO_2$ nanoparticles and $Nd_2O_3$ nanorods, during exposure to the solutions of 0.1 M $H_2SO_4$ and 3.5% NaCl was evaluated by electrochemical impedance spectroscopy (EIS) and linear polarization resistance (LPR) techniques. The nanorods of $Nd_2O_3$ were synthesized by cathodic pulse electrochemical deposition technique. The barrier properties of the different PPy coatings containing nanosized metal oxides immersed in $H_2SO_4$ solution were ranked as follows: $Nd_2O_3$ > $TiO_2$ > $CeO_2$. Therefore, the $Nd_2O_3$ coating sample provided the highest corrosion protection at any time of immersion up to 72 hours after immersing in $H_2SO_4$ solution. On the other hand, the $CeO_2$ coating sample displayed the best anticorrosive properties among the other coating samples after immersion in NaCl solution up to 28 days. This is due to the inhibition effect of cerium ions on aluminum alloys at near-neutral solutions.

• 플랜트 저널
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• 제16권3호
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• pp.47-52
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• 2020

본 연구에서는 알루미늄으로 제작된 심해 장비의 부식 저항 능력 향상시키기 위해 알루미늄 부식 방지 방법과 측정방법을 조사하였다. 조사된 부식 방지 방법은 Cathodic Protection(음극화 보호), Conversion Coating, Anodizing, 및 Organic Coating이었다. 그리고 간단하게 조사된 측정 방법은 Scanning Electron Microscope (SEM), Electrochemical Impedance Spectroscopy (EIS), Glow discharge optical emission spectrum spectroscopy (GD-OES), Fourier Transform Infrared Spectroscopy (FT-IR), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), Scanning Vibrating Electrode Technique (SVET), Contact Angle(접촉각), Interfacial Tension (경계면 장력)이었다. 알루미늄 부식을 방지하기 위해 널리 사용되는 방법은 Anodizing과 Organic Coating이었으며, 부식 측정을 위해서는 여러 방법들이 골고루 사용되었다. 그 중 많이 사용되는 방법은 표면의 구조를 관찰하 위한 SEM과 부식 저항 능력을 측정하기 위한 접촉각 측정이었다.

• 한국가스학회지
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• 제5권3호
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• pp.63-72
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• 2001

천연가스 공급용 고압 지하 매설배관에 교류가 유도될 때 쿠폰과 전기저항형 박막센서를 이용하여 교류에 의한 부식속도를 평가하고 주요한 인자를 규명하고자 하였다. 전국에 걸쳐 조사된 교류전압 측정결과를 바탕으로 쿠폰과 전기저항형 박막센서를 설치하고, 주요인자를 고찰하기 위하여 다양한 인자들 (교류전압, 교류전류, 토양 비저항, 주파수, 방식전위)을 정기적으로 기록하였다. 황산동 전극기준 -850mV의 방식전위를 충분히 만족하는 상황에서도 교류에 의한 부식이 진행하였으며, 교류에 의한 부식속도는 교류전압과는 관계없이 교류전류밀도와 주파수에 의존하는 것으로 나타났다. 교류에 의한 부식속도는 유효교류전류밀도에 따라 직선적으로 증가하였으며, 쿠폰에 의한 평가결과 직선의 기울기는 0.619, 전기저항형 센서에 의한 직선의 기울기는 0.885로 나타났다.