• Journal of Advanced Marine Engineering and Technology
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• 제19권2호
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• pp.56-66
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• 1995

Recently, with theraped advancement in th oceanology such an ocean-going vessel and oceanic structures, there is a need to study the cavitation erosion-corrosion control of pump impeller, the partial element of ocean machinery, for more effective operation. Especially, the cathodic protection (impressed current method & Al-sacrificial anode method) was applied to sea water, and Cu-alloy material mixed Zn & Al was used as a control method of cavitation erosion-corrosion. In this study, used the piezoelectric vibrator with 20KHz, 24.mu.m to cavity generation apparatus, and investigated the weight loss, weight loss rate, electrode potential & current density etc. under this condition. According to test result, thos describes how to indentify an influence of the cathodic protection and Al & Zn addition in material development for the control of cavitation erosion-corrosion, and those will serve as fundamental data on the cavitation erosion-corrosion control of oceanic centrifugal pump.

• 한국표면공학회지
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• 제48권6호
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• pp.343-348
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• 2015

In this paper, arc Zn thermal spray coating was carried out on the SS400 steel, and then various electrochemical characteristics and surface damage behavior of Zn thermal spray coating layer were analyzed. As the results, the potential of Zn thermal spray coating layer presented driving voltage above 300 mV compare to that of SS400 steel. The passivity characteristic in anodic polarization curve was not presented. It was adequate to as sacrificial anode material. In the surface damage after galvanostatic experiments, uniform corrosion tendency of Zn thermal spray coating layer was clearly observed with acceleration of the dissolution reaction. In conclusion, Zn thermal spray coating could be determined to represent the corrosion protection effect by stable sacrificial anodic cathodic protection method in seawater because it had sufficient driving voltage and uniform corrosion damage tendency for the SS400 steel.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 D
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• pp.727-728
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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.

• 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.

• 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.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.876-878
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• 2008

The galvanic corrosion of a vessel, or systems fitted to minimize the ship's corrosion such as ICCP(Impressed Current Cathodic Protection) system and sacrificial anodes, can lead to significant electrical current flow in the sea. The presence of vessel's current sources associated with corrosion will give rise to detectable electric field surrounding the vessel and can put it at risk from mine threats. For this reason, it is necessary to design corrosion protection systems so that they don't only prevent a hull corrosion but also minimize the electric field signature. In this paper, we describe theoretical backgrounds of underwater electric field signature due to corrosion and corrosion protection system on naval vessels and analysis results of the electric field according to ICCP anode arrangement.

• 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.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.1065-1068
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• 2008

해상교량은 바다에 노출되기 때문에 많은 경우 본래의 설계수명을 다하지 못하고 조기에 열화된다. 이러한 콘크리트 열화는 다공성인 콘크리트 내부에 염분이 침투함으로써 철근부식을 야기하고, 부식된 철근은 보통 $6{\sim}10$배까지 부피가 팽창하면서 콘크리트에 균열을 일으키고 결국 탈락(박리)으로 이어진다. 이와 같은 철근부식과 균열발생의 가속화는 구조물의 심각한 손상과 궁극적으로 붕괴까지 이어질 수 있다. 따라서 이러한 피해를 막기 위해서는 콘크리트 내 철근부식의 정확한 이해가 필요하며, 부식발생의 정량화에 의한 예측은 물론 적절한 방식법을 적용해야한다. 음극방식법은 비교적 최근에 개발된 철근콘크리트 구조물의 방식법 중 하나이며 요즈음도 해외 여러 나라에서 이에 대한 방식시스템 연구가 활발하다. 본 연구에서는 해상교량이나 항만부두 구조물의 상판부에 대한 예비실험 성격으로 슬랩 시험편(40cm ${\ast}$ 30cm ${\ast}$ 18cm)을 채택하였다. 시험환경은 15% 염분과 온도 $40^{\circ}C$의 가속화된 해양환경이었으며, 시험 기간 동안 주기적인 건습 반복을 실시하였다. 방식시험편은 음극방식 기술의 하나인 Zn-mesh에 의한 희생양극식을 채택하였다. 연구내용으로는 음극방식에 의한 방식성능을 관찰하였으며 신설구조물과 보수구조물에 대한 방식 효과를 비교하였다.