• Title/Summary/Keyword: Cathodic

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The Characteristic Analysis of Calcareous Deposit Films Formed on Steel Plate by Cathodic Current Process in Marine Environment (해양환경 중 음극전류 프로세스에 의해 강판에 형성된 석회질 피막의 특성 분석)

  • Park, Jun-Mu;Kang, Jae Wook;Choi, In-Hye;Lee, Seung-Hyo;Moon, Kyung-Man;Lee, Myeong-Hoon
    • Journal of the Korean institute of surface engineering
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    • v.49 no.2
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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.

A Study on Monitoring of Mitigation of Rail Corrosion using Sacrificial Anode Cathodic Protection Method (희생양극법을 적용한 철도 레일의 방식효과 모니터링 연구)

  • Choi, Jung-Youl;Park, Jong-Yoon;Lee, Kyu-Yong;Chung, Jee-Seung
    • The Journal of the Convergence on Culture Technology
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    • v.5 no.4
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    • pp.367-371
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    • 2019
  • In this study, we proposed the sacrificial anode cathodic protection method as a countermeasure to reduce the corrosion of railway rails under oceanic climatic conditions and proved the anticorrosive effect experimentally. In addition, the proposed sacrificial anode cathodic protection method were tested on site to examine long-term rail corrosion monitoring and field applicability for more than 26 months and to prove the effectiveness of rail corrosion. As a result of monitoring the corrosion state using the cellophane tape method, the appearance of the applied sections with sacrificial anode cathodic protection method was good at the present time about 26 months after the field test laying, and no abnormalities and other abnormalities of the rail welded section and the rail web were found. Hence, in places where no sacrificial anodes were installed, rust progressed rapidly. In addition, the proper spacing of sacrificial anodes was found to form the most stable corrosion coating at 1.0 ~ 1.5m. After about 26 months of monitoring, the installation of sacrificial anodes could help stabilize the overall rail corrosion level, even if the spacing was somewhat wider.

A Study on the Standardization of Performance Test Method for Cathodic Protection System in Korea (국내 전기방식 시스템의 성능평가를 위한 시험 방법에 대한 표준화 연구)

  • Bae, Jeong-Hyo;Ha, Tae-Hyun;Lee, Hyun-Goo;Kim, Dae-Kyeong;Lee, Ji-In;Kim, Suk-Won
    • Proceedings of the KIEE Conference
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    • 2002.07b
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    • pp.644-647
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    • 2002
  • Generally. the owners of the facilities adopt CP(Cathodic Protection) Systems to protect the corrosion accidents previously. The developed countries have secured the standard of CP systems through the various researches and consolidation of the rules. So in the first stage, I had been studied the international standards: JSCE, NACE Standard. ASTM, DNV, Australian Standard etc. and standardized the CP systems about items, performance. specifications and so on. In this thesis, I have been studying the results of standardization of performance test methods of CP system to apply in Korea.

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Corrosion of Silver by Outgassing from Rubber

  • Sakai, Jun'ichi;Omoda, Masataka;Ishikawa, Yuichi
    • Corrosion Science and Technology
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    • v.7 no.2
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    • pp.130-133
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    • 2008
  • Corrosion of silver by outgassed sulfur species from rubber has been investigated by means of quartz crystal microbalance technique (QCM) and cathodic reduction technique. Silver specimens were placed together with a rubber of predefined quantity in an enclosed environment. Corrosion progressed linearly with time and silver sulfide was found as the corrosion product during all the tests. No significant dependence on RH was observed, while the corrosion rate increased as temperature rose. Furthermore the corrosion rate increased logarithmically with the quantity of the rubber placed in the exposure environment. It may be suggested that the corrosion rate of silver is determined by the amount of outgassed sulfur species which is a function of temperature and the quantity of rubber contained in the exposure environment.