• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.3130-3132
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• 2000

The Cathodic Protection system which is usually applied to marine metallic structures in domestic is Sacrificial Anode Method. In general, low efficiency rectifiers are using in the field of Cathodic Protection. These rectifiers are not only low efficiency but also manual type which is not able to control remotely. In this paper we describe the high efficiency rectifier used the high speed switching method for optimum corrosion control of marine metallic structures.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 춘계학술대회 논문집
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• pp.194-194
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• 2015

본 연구에서는 PVD법 중의 하나인 스퍼터링(sputtering) 기술을 이용하여 향상된 희생양극(sacrificial anode)적 특성을 가지는 Al-Mg 막을 제작함은 물론 그 제작조건, 표면의 몰포로지, 결정구조학적 결정배향성과의 연관성을 해석 및 전기화학적 내식특성평가 등을 통하여 종합적인 결과를 고찰-정리해 보았다. 이를 통해 박막의 증착과정 중 가스압의 변화가 흡착 인히비터로 작용하여 박막의 몰포로지와 결정배향성에 미치는 영향을 분석하였으며 이러한 표면 몰포로지, 결정배향성과 내식성간 상관관계를 해석하여 최적의 Al-Mg 막 설계 지침을 제시하고자 하였다.

• 대한화학회지
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• 제46권5호
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• pp.444-456
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• 2002

차체의 산화를 방지하기 위하여 희생적 양극을 사용한 산화방지 장치를 개발하였다. 희생적 양극은 철보다 산화 전위가 높은 Mg, Al, Zn으로 만들어 졌고 이것은 차체의 철이나 철합금보다 먼저 산화되어 차체의 부식을 방지한다. 차체 산화방지 장치를 제작하여 철시편을 염산, 질산 및 황산에 대한 방식효과를 시간에 따라 측정하였고 SEM과 XPS를 이용하여 철시편 표면의 방식효과를 분석하였다. 철시편을 산화 방지 장치에 연결하면 산화되어 산성용액 속으로 녹아 들어가는 철의 양이 현저하게 감소하고 철시편 표면의 산화가 방지되며 산화된 철은 $Fe_2O_3$의 산화형태를 가짐을 확인하였다. 따라서 차체 산화방지를 차체에 직접 부착한다면 차체의 부식 및 산화를 효과적으로 방지할 것으로 기대된다.

• 한국표면공학회지
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• 제49권2호
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• pp.166-171
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• 2016

Cathodic protection is widely recognized as the most cost effective and technically appropriate corrosion prevention methodology for the port, offshore structures, ships. When applying the cathodic protection method to metal facilities in seawater, on the surface of the metal facilities a compound of calcium carbonate($CaCO_3$) or magnesium hydroxide($Mg(OH)_2$) films are formed by $Ca^{2+}$ and $Mg^{2+}$ ions among the many ionic components dissolving in the seawater. And calcareous deposit films such as $CaCO_3$ and $Mg(OH)_2$ etc. are formed by the surface of the steel product. These calcareous deposit film functions as a barrier against the corrosive environment, leading to a decrease in current demand. On the other hand, the general calcareous deposit film is a compound like ceramics. Therefore, there may be some problems such as weaker adhesive power and the longer time of film formation uniting with the base metal. In this study, we tried to determine and control the optimal condition through applying the principle of cathodic current process to form calcareous deposit film of uniform and compact on steel plate. The quantity of precipitates was analyzed, and both the morphology, component and crystal structure were analyzed as well through SEM, EDS and XRD. And based on the previous analysis, it was elucidated mechanism of calcareous deposit film formed in the sacrificial anode type (Al, Zn) and current density (1, 3, $5A/m^2$) conditions. In addition, the taping test was performed to evaluate the adhesion.

• Corrosion Science and Technology
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• 제10권3호
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• pp.101-107
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• 2011

Marine ships have played an important role as a carrier, transporting much more than 80% of all international trading, and marine transportation is an internationally competitive, strategic, and great national important industry. However, those marine ships have the characteristics such as voyage of long distance, large-volume and lower speed than the other carry system. Therefore, it is important to manufacture a larger and faster ship, however, the steel plates which are consisted with most of those ships has brought about many corrosion problems in sea water such as general corrosion, localized corrosion, cavitation and erosion corrosion etc.. Most hulls of the ships have been protected with paintings, sacrificial anode, marine growth prevention system, and impressed current cathodic protection methods against numerious corrosion problems mentioned above. However, these conventional methods are not very effective because the rudder of ships stern are exposed to very severe corrosive environment such as tides, speeds of ships, cavitations and erosion corrosion, etc.. In this study, electrochemical and cavitation characteristics was investigated for the rudder material of ship which is exposed to serious corrosive environment. As a result, it is considered that the optimum cathodic protection potentials of rudder material is the range of -0.6 V ~ -0.8 V(Ag/AgCl) in static seawater.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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• pp.271-272
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• 2006

Zinc confers high corrosion resistance by acting as a sacrificial anode, and a zinc coating improves the appearance of steel. Chromate conversion coating (CCC) films are still one of the most efficient surface treatments for steel. Although such films can self-repair via the dissolution of Cr(VI), dissolved Cr(VI) have adverse effects on humans, and the environment. Therefore, we examined the corrosion protection property and morphology of colloidal silica conversion films as an alternative to CCC films. The corrosion behavior was investigated in 3% NaCl solution using electrochemical techniques, including electrochemical impedance spectroscopy, open circuit potential, and the salt spray test(SST). Corrosion was implied by the appearance of red rust on the specimen surface. In corrosion resistance at 3% NaCl solution, red rust appeared at 15-20, 55-70, and 83-98 days on Zn-electroplated steel, colloidal silica conversion-coated specimens, and CCC-coated specimens, respectively. In the salt spray test, the colloidal silica film provided better corrosion protection than CCC films, i.e., red rust appeared at 96 hours on the Zn-electroplated steel sheet, at 432 hours with the CCC films, and at 888 hours with silica conversion coating.

• 한국해양공학회지
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• 제18권1호
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• pp.69-74
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• 2004

In general, the protection method of Shell and Tube Type heat exchanger for a vessel has been applied as a sacrificial anode, which is attached at the inner side of the shell. However, this is an insufficient protection method for tube. Therefore, a more suitable method, such as the impressed current cathodic protection for tube protection, is required. Al-brass is the raw material of tubes for heat exchanger of a vessel where seawater is used for cooling the water. It has a high level of heat conductivity, excellent mechanical properties, and a high level of corrosion resistance, due to a cuprous oxide (Cu$_2$O) layer against th seawater. However, in actuality, it has been reported that Al-brass tubes for heat exchanger of a vessel can produce local corrosion, such as stress corrosion cracking (SCC). This paper studied the effect of impressed potential on the stress corrosion cracking of Al-brass for impressed current cathodic protection in 3.5% NaCl +0.1% NH$_4$OH solution, under flow by a constant displacement tester. Based on the test results, the latent time of SCC, stress corrosion crack propagation, and the dezincification phase of Al-brass are investigated.

• 한국군사과학기술학회지
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• 제9권2호
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• pp.11-19
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• 2006

The underwater electromagnetic signatures of a naval ship are mainly generated from three sources which are the permanent and induced magnetic field in the ship's hull and other ferrous components, the cathodic current electromagnetic field established by the Impressed Current Cathodic Protection(ICCP) system or the Sacrificial Anode and the stray electromagnetic fields generated by onboard equipment. These signatures can be minimized by certain design methods or installation of signature reduction equipment. In this paper, we represented the characteristic of the underwater electromagnetic signature and the signature reduction techniques for a naval ship. Also, we measured the electromagnetic field changes emitted from the real ship using the Electric and Magnetic field Measurement System(EMMS). We found that the underwater electromagnetic signature for a naval ship can be used as input or trigger signal in a surveillance system and an influence mine.

• 한국표면공학회지
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• 제52권1호
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• pp.37-42
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• 2019

Electrodeposited zinc layer is widely used as a sacrificial anode for a corrosion protection of steel. In this study, we modified the surface of electrodeposited zinc to have a hydrophobicity, which shows various advanced functionalities, such as anti-corrosion, anti-biofouling, anti-icing and self-cleaning, due to its repellency to liquids. Superhydrophobicity was realized on electrodeposited zinc layer with a hydrothermal treatment, creating nanostructures on the surface, and following Teflon coating. The superhydrophobic surface shows a great repellency to water with high surface tension, while liquid droplets with low surface tension easily adhered on the superhydrophobic surface. However, immiscible lubricant-impregnated superhydrophobic surface shows a great repellency to various liquids, regardless of their surface tension. Therefore, it is expected that the lubricant-impregnated surface can be an alternative of superhydrophobic surface, which have a drawback for some liquids with a low surface tension.

• Corrosion Science and Technology
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• 제22권5호
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• pp.322-329
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• 2023

There are a variety of heat exchangers used in automobiles, such as shell and tube heat exchangers, double tube heat exchangers, and plate heat exchangers. Most of them are water-cooled to prevent engine overheating. There have been reports of corrosion damage to these heat exchangers due to continuous wetting caused by external temperature differences, road pollutants, and snow removal. In addition, galvanic corrosion, which occurs when two dissimilar materials come into contact, has been identified as a major cause. In this study, corrosion characteristics and galvanic corrosion behavior of Al alloy (AA3003, AA4045 and AA7072) used in automobile heat exchangers were analyzed. Effective clad materials for heat exchanger tubes and fins were also evaluated. It was found that AA7072 should be applied as the cladding material for fin AA3003 and that AA4045 was suitable as a cladding material for tube AA3003 because this clad materials application was the most effective clad design to delay the occurrence of pinhole in the tube. Main factors influencing galvanic corrosion dissolution were found to be galvanic corrosion potential difference and galvanic corrosion current density.