• Corrosion Science and Technology
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• 제8권3호
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• pp.126-131
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• 2009

The interaction between wear and corrosion can significantly increase total material losses in water chemistry environment. The corrosive wear tests of a PWR steam generator tube material (Alloy 690) against the anti vibration bar material (409 SS) were performed at room temperature. The tests were performed in alkaline water chemistry conditions. NaOH solution was selected for test condition to investigate the corrosive wear effect of steam generator tube material in alkaline pH condition without other factors. The flow induced vibration can caused tube damage and the corrosion can be occurred by water chemistry. The test results showed that, in the alkaline solution at pH 13.9, the corrosion current density was increased about ten times than that in the distilled water. And wear rate at pH 13.9 was increased about ten times from that at neutral condition. However, the wear rate was decreased with time. The decrease would be attributed to the change in roughness of specimen or sub-layer of the worn surface with time. From microstructure observation, severe abrasive shape and several wear debris were found. From those results, it could infer that the oxide film on Alloy 690 changed to easily breakable one in the alkaline water, and then abrasion with corrosion became the main wear mechanism.

• 한국환경과학회지
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• 제24권7호
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• pp.907-915
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• 2015

The tap water is generally known to be corrosive in the pH range at 6.5 ~ 7.5. And the degree of corrosion varies depending on the types of raw water such as river surface water or lake water of the dam. Although several corrosion index represents the corrosivity of tap water, the typical corrosion indexes such as Langelier saturation index (LI) and calcium carbonate precipitation potential (CCPP) were calculated to monitoring the corrosive water quality about raw and tap water in water distribution system. To control the corrosive water quality, the correlation between corrosion index and water quality factors were examined. In this study, corrosion index (LI, CCPP) and the pH was found to be most highly correlated.

• 한국물환경학회지
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• 제33권3호
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• pp.359-369
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• 2017

Water distribution systems supply drinking water to consumers' taps. Internal corrosion of metallic pipe used in drinking water distribution systems has reduced water quality and led to increased levels of toxic heavy metals such as lead, copper and nickel. These problems have been experienced to varying degrees by water utilities in many countries. North America has successfully managed and controlled pipe corrosion and corrosive water in water distribution system based on various policies, regulations and rules. Practical and engineering guidelines for evaluation of pipe corrosion and determination of treatment options are also provided to assist drinking water supplies. In addition, the corrosion mechanism in water distribution systems, such as the complex effects of physical and chemical parameters on the corrosion pipes has been improved to accurately predict corrosion rates of metallic pipes in actual water distribution systems. This paper reviews various regulations, policy statement, and treatment produces on controlling corrosion in drinking water distribution systems in US and Canada and then offers suggestion for management of corrosive water and pipe corrosion in drinking water distribution system in Korea.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.187-187
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• 2011

Nowadays, the issue of solar cell durability in local weather and environment is a crucial issue. Above all, surface corrosion on solar cell multilayers is a major factor that determines the durability of commercial solar cells; corrosive chemical interactions between air, humidity and chemical species and solar cell multilayers can unfavorably affect the durability. Here, we study microscopic and spectroscopic surface techniques to investigate the corrosive interaction on the antireflective layers of solar cell multilayers under various conditions such as acid, base, constant temperature and humidity. Surface morphology and adhesion force were characterized with atomic force microscopy before and after chemical treatment. Chemical composition, and transmittance factors were studied with X-ray photoelectron spectroscopy, and ultraviolet-visible spectroscopy, respectively. Based on these studies, we suggest the dominant factors in the corrosive chemical processes, and their influences on the structural, compositional, and optical properties of the antireflective layers.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.551-560
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• 2009

Introduced was a new anti-corrosive method with improved ease of construction, economy, and durability that could be applicable for steel-composite drilled shaft. The feasibility and economy of sea-water-resistant steel was evaluated under the assumption that it was to substitute carbon steel for steel casing of drilled shaft foundation as a load carrying structural member not just as a sacrifice casing, and that anti-corrosive protection measures as required by the domestic standards was applied. Sea-water-resistant steel was found to cost 30% to 55% more, depending on pile diameter and the type of applied anti-corrosive measures, than carbon steel for the service life time of 70 years: 50% to 90% more for 100 years of service life.

• 콘크리트학회지
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• 제11권2호
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• pp.251-259
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• 1999

최근 다양한 침해환경에 건설되는 구조물이 증가함에 따라 철근 및 강재의 부식위험성이 높아지면서, 철근 콘크리트 구조물의 내구성 저하문제가 큰 관심으로 떠오르고 있다. 특히 해양 환경하에 건설된 철근 콘크리트 구조물의 경우 구조물 외부로부터 침투되는 염분의 영향으로 인한 철근부식이 발생 및 진행되어 콘크리트 구조물에 균열, 박리 등의 손상을 받게된다. 그러므로 해양콘크리트 구조물은 염해에 대해 내구성 및 신뢰성 확보가 중요시되고 있다. 따라서, 본 연구에서는 철근의 부착강도를 크게 감소시키지 않게 하는 방법으로서 시멘트 계통의 방청시멘트를 철근에 도막한 후 내부식성능과 부착강도특성을 실험적으로 연구하였다. 본 연구결과, 방청시멘트 도막철근은 소요의 내부식성능을 갖고 있으면서도 부착강도특성도 일반철근과 유사하였으며, 앞으로 실구조물의 내구성증진을 위해 효율적으로 사용될 수 있는 토대가 될 것으로 사료된다.

• 상하수도학회지
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• 제23권1호
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• pp.77-87
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• 2009

In existing systems, the best method inhibiting corrosion control in water distribution systems is to reduce water corrosiveness. Water corrosion can be decreased by controlling water quality through simple water treatment in treatment plants. On this research, we study the characteristics of tab water qualities in domestic areas, assessment of corrosive water quality and the method of water quality monitoring. This review presents the method of water quality monitoring which is the most applicable. Monitoring for corrosion control in waterworks system is the most proper method; It can prevent serious accidents economically and reduce civil appeals. Surely we should assess corrosive water quality in tab water, and introduce water treatment methods to control corrosive water quality before monitoring for corrosion. According to a lot of researches, it has been proved that simple water treatments can reduce the pipe corrosion. In this review we should indicate that we do not control of the corrosive water quality due to domestic conditions, we should monitor the water quality basically. Therefore, we recognize how the existing water quality can cause problems on pipeline corrosion, how to deal with it. Then it will be possible to apply water quality monitoring for corrosion control in water distribution system. Monitoring for corrosion control can be expressed by LI index, it is already known in literatures. This review presents more simple method than existing methods than existing ones we expect to apply these methods to SCADA in the future.

• 한국해양공학회지
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• 제23권4호
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• pp.64-68
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• 2009

It has been observed that coated steel structures deteriorate more rapidly than the designed lifetime due to acid rain caused by air pollution, etc. Therefore, improving the corrosion resistance of anti-corrosive paint is very important in terms of safety and the economic point of view. In this study, the corrosion resistance of five kinds of anti-corrosive paints, including the Acryl, Fluorine, and Epoxy resin series, were investigated with electrochemical methods, such as corrosion potential measurements, polarization curves, diffusion limiting current density, etc. As a result, the corrosion resistance of the F101 specimen with the fluorine resin series was found to be superior to the other specimens, while E100 with the epoxy resin series also showed a somewhat good corrosion resistance. Furthermore, it was observed that the amount of water and oxygen entering the inner side of a painted film increased with an increase in immersion time, irrespective of the kind of resin series. However, the oxygen diffusion limiting current density of a specimen with good corrosion resistance was relatively decreased compared to other specimens, because of the difficulty of oxygen diffusion penetrating to the inner side of the film. Consequently it is suggested that we can qualitatively evaluate the corrosion resistance of an anti-corrosive paint by measuring the diffusion limiting current density as an electrochemical method.

• 한국해양공학회지
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• 제17권6호
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• pp.77-82
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• 2003

The absorption of water into an anti-corrosive organic coating, such as alkyd and urethane resin coating, was investigated, using a quartz crystal microbalance (QCM). Anticorrosive properties of the coatings were also measured, by means of electrochemical impedance spectroscopy (EIS). The overall absorption of water in the coating is determined by the chemical nature of resin, and decreases with increasing thickness. The enhancement of anti-corrosive performance, through increase of coating thickness, was more remarkable in the case of the coating that hadlower equilibrium water absorption. The absorption kinetics curves were Fickian in nature. The EIS analysis confirmed that the resin, having lower equilibrium water absorption, shows higher anti-corrosive performan.

• 한국철도학회논문집
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• 제5권1호
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• pp.32-39
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• 2002

As most railways are gradually electrified with modernized electric cars, the demand for catenary wires and their facilities are also increased. Catenary Wires are exposed to the marine area with air-borne salt or severely polluted industrial area with much corrosive emission gases depending on the locations. Corrosion of catenaty wires can make their actual lifetime shorter than that originally designed. Thus, the messenger and ACSR wires, kinds of catenary wire system, were investigated with respect to corrosion, which include new and used ones collected at the field. Tensile strengths and elongations appeared to decrease when the wires were exposed to corrosive environments. The amount of decrease was more prominent as environmental conditions became more corrosive. They are also vibrated with some amplitude everytime pentographs touch contact line. The frequent cyclic load on the wire may result in a fatigue damage. Surface damage by corrosion can make fatigue crack initiate with ease. In the present study, the fatigue life of the used wire was measured 50 to 60% compared with that of new one in average.