• Title/Summary/Keyword: Sacrificial Anode

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A Study on the Characteristics of Cathodic Protection by Al-Alloy Sacrificial Anode in Marine Environment (해양환경중에서 A1-합금희생양극에 의한 음극방식특성)

  • 이연호
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.28 no.1
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    • pp.53-60
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    • 1992
  • In this study, cathodic protection experiment was carried out by Al-alloy sacrificial anode in marine environments which have specific resistance($\rho$) if 25~7000$\Omega$.cm and investigated protection potential, current density and loss rate of Al-alloy sacrificial anode. The main results resistance($\rho$) of 400$\Omega$.cm, the cathodic protection potential appears high about-720 mV(SCE). But below specific resistance($\rho$) of 300$\Omega$.cm, the cathodic protection potential appears low about-770 mV(SCE) and simultaneously, cathode is protected sufficiently. 2) The loss rate of Al-Alloy sacrificial anode became large with decreasing specific resistance and increasing the ratio(A sub(c)/A sub(a) of bared surface area of anode and cathode. 3) The loss rate of Al-alloy sacrificial anode(w) to the mean current density of anode(i) is as follows. w=ai+b (a, b : experimental constants)

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Effect of Cathodic Protection of Adjacent Steel Piles on the Life of Sacrificial Anode (희생양극의 수명에 미치는 인접 강파일의 음극방식 영향)

  • Moon, Kyung-Man;Lee, Kyu-Hwan;Cho, Hwang-Rae;Lee, Myung-Hoon;Kim, Yun-Hae;Kim, Jin-Gyeong
    • Journal of Ocean Engineering and Technology
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    • v.22 no.3
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    • pp.76-81
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    • 2008
  • There are two cases when the life of a sacrificial anode is shortened from the designed life: one case results from self-corrosion of the anode due to contamination by sea water in the other case, however, electrical current to protect some given steel piles overflows to protect other, adjacent non-protected steel piles. In this study, the variation of polarization potential of nine steel piles, being protected cathodically and with anode-producing current between anode and steel piles, was investigated. Parameters were varied, such as the eighth and ninth steel piles either connected electrically or not, and whether the ninth steel pile was protected by another sacrificial anode or not. The current produced by the sacrificial anode decreased when the ninth steel pile was cathodically protected by the anode of another pile. However, produced current increased when the ninth steel pile was not connected to another anode. The study concludes that the life of a sacrificial anode can be prolonged or shortened depending on whether adjacent steel piles are cathodically protected or not.

A Study on the Influence of Al Alloy Sacrificial Anode Efficiency due to Marine Environmental Variation (해양환경 변화가 알루미늄합금 희생양극의 효율에 미치는 영향에 관한 연구)

  • 김도형
    • Journal of Ocean Engineering and Technology
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    • v.14 no.2
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    • pp.106-111
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    • 2000
  • Recently it was reported that the life of Al Sacrifical anode is being used in port piers has been significantly shortened compared with the original design life (e.g. average life shortened from 20 years to 13-15 year) Those factors involving these problems mentioned above were seemed to be a quality of anode material and diverse environmental factors such as pH flow rate temperature Dissolved oxygen Chemical oxygen demand and resistivity etcm In this study flow rate and contamination degree(pH) of sea water affecting to sacrificial anode life hve been investigated in terms of electrochemical characteristics of Al alloy sacrificial anode It was known that the lifetime of Al alloy anode was shortened not only by increasing of self-corrosion quantity by varying flow rate of sea water but also by increasing corrosion current density due to the potential difference increment between Al anode and steel structure cathode by varying contamination degree of sea water. Especially when anode current density is from 1mA/cm2 to 3mA/cm2 and flow rate of sea water is under 2m/s anode current efficiency is 90% above However flow rate is over 2m/s anode current efficiency fell down sharply due to erosion corrosion as well as galvanic corrosion.

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A Study on Mitigation of Rail Corrosion using Sacrificial Anode Cathodic Protection Method (희생양극법을 이용한 레일부식 저감 방안에 관한 연구)

  • Choi, Jung-Youl;Kim, Jun-Hyung;Lee, Kyu-Yong;Kim, Young-Ki;Park, Jong-Yoon;Song, Bong-Hwan;Seol, Jin-Woong
    • Journal of the Korean Society of Safety
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    • v.32 no.6
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    • pp.54-60
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    • 2017
  • A railway rail will be corroded by the repetitive sea wind and fog in the splash and tidal zone such as Youngjong grand bridge. And these rusts of rail could be increased by increasing service period, and it frequently occurred the safety accidents or disorders in electrical problem. In this study, the sacrificial anode cathodic protection method was proposed as a measures for reducing the corrosion of the railway rails in the oceanic climate conditions. As the results of immersion test using the salt water during four months, the sacrificial anode cathodic protection method using the aluminum anode(Al-anode) was evaluated that a distinct effect on corrosion reduction in the rails. Therefore the sacrificial anode cathodic protection method was experimentally proven that a disorders in aspects electric and signal of railway operation condition such as direct fixation track system in Youngjong grand bridge could be prevented by reducing rust falling from the rail. In addition, the installation conditions of the anodes directly affect the transmission range of corrosion potential, the sectional loss of anode, and the corrosion reduction effect. Therefore, to expect the corrosion reduction effect of rails under the oceanic climate conditions for railway track, it was important to adopted the appropriate spacing of anode installation by considering the actual field conditions.

Critical Design Issues on the Cathodic Protection Systems of Ships

  • Lee, Ho Il;Lee, Chul Hwan;Jung, Mong Kyu;Baek, Kwang Ki
    • Corrosion Science and Technology
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    • v.6 no.3
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    • pp.90-95
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    • 2007
  • Cathodic protection technology has been widely used on ship's outer hull and inner side of ballast water tanks as a supplementary corrosion protection measure in combination with protective organic coatings. Impressed current cathodic protection system is typically opted for the ship's hull and, sacrificial anode system, for ballast water tanks. The anticipation and interest in cathodic protection system for ships has been surprisingly low-eyed to date in comparison with protective coatings. Computational analysis for the verification of cathodic protection design has been tried sometimes for offshore marine structures, however, in commercial shipbuilding section, decades old design practice is still applied, and no systematic or analytical verification work has been done for that. In this respect, over-rotection from un-erified initial design protocol has been also concerned by several experts. Especially, it was frequently reported in sacrificial anode system that even after full design life time, anode was remaining nearly intact. Another issue for impressed current system, for example, is that the anode shield area design for ship's outer hull should be compromised with actual application situation, because the state-of-the-art design equation is quite impractical from the applicator's stand. Besides that, in this study, some other critical design issues for sacrificial anode and impressed current cathodic protection system were discussed.

A Study on the Rebar Corrosion Control in Concrete by Using the Sacrificial Anode Cathodic Protection (희생양극법을 이용한 콘크리트중의 철근부식 억제 효과에 대한 연구)

  • 문한영;김성수;김홍삼;김성섬
    • Proceedings of the Korea Concrete Institute Conference
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    • 1997.10a
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    • pp.299-302
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    • 1997
  • Generally the corrosion expansion of the steel due to outdoor corrosive environmental factor brings about serious problem on the durability of concrete structures. It is the purpose of this study to see whether adapted sacrificial anode method is effective or not. from the experimental results. the potential of steel in concrete in case of adapting the sacrificial anode method satisfies protection standard value (less than -850mV vs CSE).

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Effect of the Chathodic Protection in Concrete by Applying Sacrificial Anode System (희생양극방식을 응용한 콘크리트 중의 철근의 전기방식 효과)

  • 김성수;김홍삼;김진철;김종필;박광필
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.05a
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    • pp.87-92
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    • 2001
  • Reinforced concrete have defect in durability due to carbonation, freezing and thawing, and penetration of chloride ions with time in spite of superb structure. Especially steel corrosion in concrete due to penetration of chloride ions have result in a marked decline in service life. The principal purpose in this study is to see effect of sacrificial anode cathodic system, one of the electrochemical methods in order to the control of steel corrosion in concrete. There are chloride content in concrete in cracked and no cracked specimen with cathodic protection. To recognize the effect of sacrificial anode cathodic protection, Instant-off potential are measured. We have the excellent effect for control steel corrosion adaption sacrificial anode cathodic system.

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Effects of the Protection for Rebars by Embeded Sacrificial Anode in Concrete (희생양극재의 매입에 의한 콘크리트 중의 전기방식 효과)

  • 김성수;김홍삼;김종필
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.1207-1212
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    • 2001
  • Reinforced concrete has defects in durability due to carbonation, freezing and thawing, and penetration of chloride ions with elapse of time in spite of super structure. Especially steel corrosion in concrete due to penetration of chloride ions has result in a severe decline in service life. The principal purpose of this study is to estimate effects of sacrificial anode cathodic system, one of the electrochemical methods in order to control of steel corrosion in concrete. There are chloride content in concrete in cracked and non cracked specimen with cathodic protection. To investigate the effect of sacrificial anode cathodic protection, potential-decay with current density, corrosion ratio, etc. are measured. We have the excellent effect for control steel corrosion adaption sacrificial anode cathodic system.

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Effect of concentration of H2SO4 on electrochemical properties of equipped Al sacrificial anode to prevent the corrosion and discolor of silver surface (은의 표면 부식 및 변색을 방지하기 위해 설치된 Al 희생양극의 전기화학적 특성에 미치는 황산 농도의 영향)

  • Shin, Byung-Hyun;Chung, Won-Sub
    • Journal of the Korean institute of surface engineering
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    • v.54 no.1
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    • pp.12-17
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    • 2021
  • Among the various precious metals, silver is used in various fields because of its low price than other precious metals. However, the surface of silver remains after rain in the atmosphere containing sulfur ions and chlorine ions, causing silver corrosion and discoloration. Existing documents have developed a anode to prevent corrosion but that are concentrated on secondary batteries. This study tried to prevent corrosion and discoloration of silver by using an Al sacrificial anode. Sulfuric acid decreased the potential of silver and increased the current density at active polarization and OCP. The amount of corrosion of silver with the Al sacrificial anode was reduced from 0.5 % to 6.5%. When silver is used for decoration outside, corrosion and discoloration of silver can be suppressed by installing an Al anode.

Electrochemical Evaluation of Corrosion Properties of Aluminum Alloy as a Sacrificial Anode for Offshore Structure Protection (해양구조물의 방식을 위한 알루미늄 합금의 희생양극적 부식 특성의 전기화학적 평가)

  • Rhee, Jin-Ho;Lee, Jae-Ho
    • Journal of the Korean institute of surface engineering
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    • v.48 no.2
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    • pp.68-72
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    • 2015
  • The corrosion behavior of metals and alloys for the safety of offshore structures in seawater was investigated for the application of sacrificial anodes. The experiments were focused on the polarization behaviors and the surface morphology of each metal after experiments. Pure Zn, pure Al (Al1050), Al alloys (Al5052, Al6061), Mg alloys (AZ31, AZ91D) and steel (SCM440) were assessed in 3.5% sodium chloride solution by means of potentiodynamic polarization to verify the galvanic corrosion potential ($E_{couple}$). Potentiostat plots were plotted to compare the surface and corrosion current density ($i_{couple}$) of metals as sacrificial anodes in seawater to protect steel alloy as a cathode. Al alloys showed the best performance as a sacrificial anode, on the other hand, Mg alloys showed overprotection behavior. The surface morphologies of sacrificial anodes were observed by FESEM and compared.