• Corrosion Science and Technology
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• 제21권1호
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• pp.1-8
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• 2022

The use of cathodic protection for metals can be achieved by sacrificial anode CP or impressed current CP, or a combination of both. Cathodic protection is a highly effective anti-corrosion technique for submerged metals or metals in soil. But because the non-immersion atmospheric automobile environment is a high resistance environment, it is limited by fundamental cathodic protection. However, the application of cathodic protection to automobiles is attractive because of the possibility of maintaining corrosion resistance while using lower-cost materials. A commercially available product for automobiles that uses both sacrificial anode CP and impressed current CP was tested in a periodic salt spray environment to investigate the performance of the devices. Experimental results show that the metal to be protected has different anti-corrosion effects depending on the distance from the anode of the device, but it is effective for the entire 120 cm long specimen exposed with one anode. The cathodic protection is effective because the conductive tape attached to the anode of the structure to be protected acts as a constant electrolyte in wet and dry conditions. The results show that the entire standard passenger car can be protected by cathodic protection with 4 anodes.

• Corrosion Science and Technology
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• 제11권6호
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• pp.242-246
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• 2012

This measurement represents the effectiveness of sacrificial anode cathodic protection (SACP) system in a coastal bridge structure. To verify the cathodic protection (CP) effect, the monitoring sensor (DMS-100) that could measure potential, corrosion rate, current, concrete resistivity, and temperature was embedded. The measurement conducted for three years after CP system was installed. Specifically, due to the fact that fresh water and sea water was repeated in the bridge structure, this bridge structure presented special CP behavior. Measurement factors were CP potential, CP current, concrete resistivity, and depolarization potential. In addition, visual inspection was also carried out. As a result of current and depolarization measurement, CP system was well activated in most piers.

• Corrosion Science and Technology
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• 제8권5호
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• pp.177-183
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• 2009

There are two effective methods in use to protect ship ballast tank against corrosion. One is paint coating and the other cathodic protection(CP). The conventional cathodic protection design has mainly relied on the expert's experience. During the last two decades computer modeling has been significantly developed as an advanced design technology for cathoidic protection systems not only for ships, but also for offshore structures. However the present computer modeling of cathodic protection systems have some limitations simulating corrosion in the ballast tank with a deteriorated coating. In this study, "coating breakdown factor" considering coating degradation states with time has been attempted to improve the cathodic protection modeling using the data from literatures.

• Journal of Advanced Marine Engineering and Technology
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• 제37권3호
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• pp.260-265
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• 2013

Impressed current cathodic protection (ICCP) system is one of the most promising corrosion protection methods. The Effect of ICCP system can be changed at diverse conditions. Particularly, temperature and relative humidity plays a crucial role in CP (Cathodic Protection) effect. Thus, in this study, the influence of temperature and relative humidity on concrete specimens was investigated. Specimens were concrete slab type with a base of $400mm{\times}400mm$ and height of 70mm. To enhance the effect of CP system, seawater was used as an electrolyte. Used anode for ICCP system was mixed metal oxide (MMO) titanium. Test factors were natural potential, CP potential, CP current, and 4-hour depolarization potential. From this study, it could be confirm that CP potential and current were highly influenced by temperature and relative humidity.

• Corrosion Science and Technology
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• 제11권3호
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• pp.77-81
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• 2012

Cathodic protection(CP) is widely used as a means of protecting corrosion for not only marine structures like ship hulls and offshore drilling facilities, but also underground structures like buried pipelines and oil storage tanks. The principle of CP is that the anodic dissolution of metal can be protected by supplying electrons to the cathode metal. When unprotected structures are nearby to CP systems, interference problems between unprotected and protected structures may be happened. The stray current interference can accelerate the corrosion of nearby structures. So far many efforts have been made to reduce the interference in the electric railway systems adjacent to the underground metal structures like buried pipelines and gas/oil tanks. During recent few decades the protection technologies against stray current induced corrosion have been significantly improved and a number of techniques have been developed. However, there is very limited information an marine environments. Some complex harbor structures are protected by two cathodic protection systems, i.e. sacrificial anode cathodic protection(SACP) and impressed current cathodic protection(ICCP). In this case, when the protection current from sacrificial anodes returns to the cathode through electrolyte, it passes through nearby other low resistance metal structures. In many cases the stray current of ICCP systems influences the function of SACP. In this study, the risk of stray current from the SACP system to adjacent reinforced concrete structures has been verified through laboratory experiments. Concrete and steel pile structures modeled a part of bridge have been investigated in terms of CP potential and current between the two. The variation of stray current according to the magnitude of ICCP/SACP has been studied to mitigate it and to suggest the proper protection criteria.

• Corrosion Science and Technology
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• 제17권6호
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• pp.272-278
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• 2018

Reinforced concrete (RC) has been used as a construction material in various environments, such as airports, bridges, and ocean concrete structures, etc. Over time, however, rebar in the concrete is prone to corrosion from environmental forces and structural defects of the concrete. Cathodic protection (CP) was invented to prevent problems with corrosion and is widely used for different applications. Cathodic protection is divided into two types: sacrificial anode cathodic protection (SACP) and impressed current cathodic protection (ICCP). There are several limitations to the use of sacrificial anode cathodic protection in complex reinforced concrete structures, including concrete resistivity, throwing power of the CP, and environmental conditions. These limitations can affect the protection performance of SACP. Therefore, we used impressed current cathodic protection in our study. We tested Ti-Mesh, Ti-Rod, and Ti-Ribbon anodes in slab type reinforced concrete specimens. Electrochemical tests were conducted to confirm the impressed current cathodic protection performance under different environmental conditions.

• International Journal of Ocean System Engineering
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• 제3권2호
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• pp.90-94
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• 2013

This study represents the recent laboratory results from cathodic protection (CP) system with the use of sacrificial anodes at different environmental conditions (temperature of $10^{\circ}C$ and $40^{\circ}C$). Specimens were slab type with a dimension of $500mm{\times}50mm{\times}100mm$, and concrete cover thickness were 25mm. Zinc mesh and/or bulk type anodes were installed at the center of specimen to confirm the distance that CP system has influences on the specimen to distribute uniform CP current to rebar. Two different kinds of temperature condition were applied to verify the effect of temperature. Experiments were conducted for 60 days, and the distribution of potential and current that supplied from anode to rebar was measured. From the results, CP potential was varied with time, and temperature played an important role in CP potential variations. Current was also changed with time, and current distribution could be improved by installing additional bulk type anode.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.395-400
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• 2005

The ship hull part is always exposed to severe corrosive environments. Therefore, it should be protected in appropriate ways to reduce corrosion problems. So there are two effective methods in order to protect the corrosion of ship hull. One is the paint coating as a barrier between steel and electrolyte (seawater) and the other is the cathodic protection(CP) supplying protection current. In the conventional design process of the cathodic protection system the required current densities of protected materials have been used. However, the anode position of field or laboratory experiment for obtaining the required current density for CP is significantly different from anode position for real structures. Therefore, the recent CP design must consider the optimum anode position for potential distribution equally over the ship hull. The CP design companies in the advanced countries can obtain the potential distribution results on the cathodic materials by using the computer analysis module. This study would show how to approach the potential analysis in the field of corrosion engineering. The computer program can predict the under protection area on the structure when the boundary condition and analysis procedure are reasonable. In this analysis the polarization curve is converted to the boundary condition in material data.

• Corrosion Science and Technology
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• 제6권6호
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• pp.269-274
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• 2007

The corrosion of steel in concrete is significant in marine environment. Salt damage is one of the most detrimental causes to concrete bridges and port structures. Especially, the splash and tidal zones around water line are comparatively important in terms of safety and life-time point of view. During the last several decades, cathodic protection (cp) has been commonly accepted as an effective technique for corrosion control in concrete structures. Zn-mesh sacrificial anode has been recently developed and started to apply to the bridge column cp in marine condition. The detailed parameters regarding Zn-mesh cp technique, however, have not well understood so far. This study is to investigate how much Zn-mesh cp influences along the concrete column at elevated temperature. About 100 cm column specimens with eight of 10 cm segment rebars have been used to measure the variation of cp potential with the distance from Zn-mesh anode at both $10^{\circ}C$ and $40^{\circ}C$ in natural seawater. The cp potential change and current diminishment along the column specimens have been discussed for the optimum design of cp by Zn-mesh sacrificial anode.

• Journal of Advanced Marine Engineering and Technology
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• 제40권6호
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• pp.510-515
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• 2016

최근 우리나라의 남해고속도로 상에 있는 해상 교량의 교각에서 부식이 발생하였다. 이 해상 교량의 부식 손상부위를 보수하기 위하여 희생양극식 전기방식을 설치하였다. 본 연구에서 소개한 해상교량의 경우, 구조물의 상부에서는 부식이 발생되지 않았기 때문에 해수에 의한 조수간만의 영향을 받는 간만대와 비말대 부분에만 희생양극식 전기방식을 설치하였다. 해상교량에 희생양극식 전기방식을 설치한 후 약 8년이 경과된 시점에서 희생양극식 전기방식의 성능을 검증하기 위하여 방식전류, 방식전위 및 복극량을 측정하였다. 전체 60개의 교각에 설치된 희생양극식 음극방식의 성능에 관한 실험 결과는 방식 양호(13개 교각), 부분 방식(27개 교각), 일시적 오류(7개 교각), 피복 들뜸(13개 교각)과 같이 4부분으로 분류하였다. 방식성능이 불량한 교각에 대해서는 양극의 추가 설치 및 Jacket 시공 등과 같은 추가적인 조치가 필요하다고 판단된다.