• Corrosion Science and Technology
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• 제15권2호
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• pp.69-77
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• 2016

In the present study, polyester-melamine coating systems with natural wood fiber (NWF) were prepared and the effects of NWF on the corrosion protectiveness of the polyester-melamine coating were examined using EIS analysis. From the results, higher average surface roughness was observed with increase of NWF content. Water diffusivity and water uptake into the polyester-melamine coatings with NWF were much higher than that into the pure polyester-melamine coating. The decrease in the impedance modulus |Z| was associated with the localized corrosion on carbon steel, confirming that corrosion protection of the polyester-melamine coatings with NWF well agrees with its water transport behavior.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.544-547
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• 2003

The owner of water pipeline has a burden of responsibility for the protection of corrosion and the prevention against leakage of water. So, they have been installed a CP(Cathodic Protection) System in odor to protect corrosion. And they also have been measured and analyzed the data about P/S(Pipe to Soil) potential of water pipeline. The P/S potential is basic data of evaluation for water pipeline corrosion. They need remote automatic corrosion monitoring system for easy maintenance. In this paper, The communication method was studied mainly. And the specifications of proposed TRS (Truncked Radio System ) terminal for corrosion monitoring are introduced briefly.

• Corrosion Science and Technology
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• 제22권2호
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• pp.90-98
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• 2023

In this study, cobalt oxide (Co₃O₄) and cobalt-doped magnetite (CoFe₂O₄) nanoparticles were synthesized by a hydrothermal method. They were then used as corrosion inhibitors for corrosion protection of AA2024-T3 aluminum alloys. These obtained nanoparticles were characterized by x-ray diffraction, field-emission scanning electron microscopy, and Zeta potential measurements. Corrosion inhibition activities of Co₃O₄ and CoFe₂O₄ nanoparticles were determined by performing electrochemical measurements for bare AA2024-T3 aluminum alloys in 0.05 M NaCl + 0.1 M Na₂SO₄ solution containing Co₃O₄ or CoFe₂O₄ nanoparticles. Corrosion protection for AA2024-T3 aluminum alloys by a water-based epoxy with or without the synthesized Co₃O₄ or CoFe₂O₄ nanoparticles was investigated by electrochemical impedance spectroscopy during immersion in 0.1 M NaCl solution. The corrosion protection of epoxy coating deposited on the AA2024-T3 surface was improved by incorporating Co₃O₄ or CoFe₂O₄ nanoparticles in the coating. The corrosion protection performance of the epoxy coating containing CoFe₂O₄ was higher than that of the epoxy coating containing Co₃O₄.

• 한국항만학회지
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• 제12권1호
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• pp.145-154
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• 1998

Protection characteristics of the corroded steel pile which was served as a pier structure over 8 years in seawater have been examined in terms of corrosion potential, electrochemical impedance spectroscopy(EIS) and anodic/cathodic polarization curves. The steel structure was sectioned into two parts, waterline(splash zone, just above the seawater surface) and in-water(underwater), and protection characteristics for the two parts were investigated with the application of cathodic protection(CP) by sacrificial anodes using Zn and Al alloys. The main results obtained were as follows; (1) The corrosion potential of waterline zone was higher than that of in-water, which implied that the corrosion of waterline was more severe than that of in-water, (2) As a result of EIS examination, the transition period from the apparent CP to the substantial CP took about twenty to thirty days according to the corrosion condition.

• 수산해양교육연구
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• 제17권1호
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• pp.106-114
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• 2005

This paper is a study on the prevention of crevice corrosion for a stainless steel heat exchanger in various pH solutions and with Cl ion concentrations. The electrochemical polarization test and crevice corrosion test of STS 304 for a heat exchanger were carried out. The crevice corrosion aspect, a passive behavior, crevice corrosion behavior, and corrosion protection characteristics of STS 304 using Al-alloy and Mg-alloy galvanic anode were considered. The main results are as follows: 1. The crevice corrosion of STS 304 occurs in the crevice and this corrosion increases pitting according to depth direction. On the other hand, the exterior crevice becomes passive. 2. With changing from a neutral to acid environment and increasing Cl ion concentration, the pitting potential of STS 304 lowers, and thus the crevice corrosion of STS 304 is sensitive. 3. The cathodic protection potential of STS 304 in the crevice is cathodically polarized by increasing Cl ion concentration. Therefore, an Al-alloy galvanic anode is more suitable than a Mg-alloy galvanic anode to protect the crevice corrosion of STS 304.

• 콘크리트학회지
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• 제11권2호
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• pp.221-230
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• 1999

콘크리트 구조물에 균열이 생겨 물과 산소의 침투확산이 용이해 지거나 또는 외부로부터 염소이온과 같은 염화물이 침투확산되어 콘크리트 중의 철근까지 도달할 경우 및 콘크리트의 중성화가 철근위치까지 진행될 경우 철근의 부동태 피막은 파괴되어 부식이 급진전 되며 콘크리트의 박리 및 탈락현상이 수반될 뿐만 아니라 구조물의 내구성이 크게 저하된다. 본 연구에서는 콘크리트 중의 철근부식을 억제하기 위한 한 방안으로 적용되는 전기방식의 이론적인 고찰과 콘크리트 내부에 다량의 염화물을 함유시키거나 또는 균열을 발생시킨 시험체에 대하여 외부전원법을 활용한 실내실험을 실시하여 철근의 방식효과에 대해 고찰하였다. 외부전원법에 의한 전기방식을 실시하여 복극량을 측정한 결과 대상 시험체 모두 NACE의 방식기준을 만족하였으며, 부식면적율의 측정결과 34 ~84%, 단면감소의 경우 84 ~ 86%의 방식효과를 확인하였다.

• Corrosion Science and Technology
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• 제6권3호
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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.

• 조명전기설비학회논문지
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• 제24권11호
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• pp.23-29
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• 2010

The principal factor determining an optimum design method for cathodic protection is finding the protection current for preventing the corrosion of existing, already laid pipe. Some factors currently used to test designs include the sizes and lengths of pipes, soil resistivity, and the coating damage rate. We believe this method and current formulae are not optimum due to the uncertainty of determining the coating damage rate and the corrosion protection current's density. This paper analyzes the amount of protection current obtained by performing a temporary current test using data describing existing laid pipe. We then propose determining the corrosion protection current by using the temporary current test after modifying the formula. In addition, we suggest a way to choose optimized cathodic protection and the process of design by executing the design and taking account of such factors as a site condition of 34km-long non-protected water supply pipe lines (stages I and II) in ${\bigcirc}{\bigcirc}$ region, climate, interferences, and durability.

• 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.

• 한국표면공학회지
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• 제49권5호
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• pp.408-415
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• 2016

The offshore structures exposed to harsh corrosive such as the marine environment is essential for the quality management technique throughout the life cycle of initial design, construction and operation. Also, it should satisfy the design life and ensure the safety of the substructure with optimization of design process. This study focused on optimization of design condition for corrosion protection of wind turbine structure and computational analyzing was performed to evaluate the performance of corrosion protection with utilizing practical experimental data. We expect this analytical study contribute to improve the corrosion maintenance stability and economical efficiency of designing wind turbine structures. As a result, the design of cathodic protection system using sacrificial anodes required accurate identification of current density in order to meet the long term design life, which can be seen that a change of structure surface's coating breakdown factor is one of the key influencing factors.