한국부식방식학회

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압력용기 클래드 보수용 전해니켈도금 인자 관계 연구
Pure nickel with a thickness of 1 mm was plated on type 304 stainless steels and low alloy steels (JIS G3131 SPHC) by electrolytic plating method in a circulating plating bath. Plating performance, mechanical properties, and surface haracteristics were evaluated in terms of pretreatment process, anode material, pH, current density, and flow rate of the plating solution. Addition of hydrochloric acid during pre-treatment process improved the adhesion performance of plating. To improve plating efficiency, it is desirable to use S-nickel rather than electrolytic nickel. The use of S-nickel was also confirmed to be desirable for maintaining the pH and concentration of the plated solution. The defect of the plating using S-nickel anode produced pit on the surface. However, it is believed that proper control can be obtained by increasing the flow rate. Internal stress and hardness values of electrolytic nickel plating according to current density need to be carried out with further studies.
KEYWORDs : Nuclear power plant, Reactor vessel, Cladding, Corrosion, Ni plating
AUTHORs : 김민수·황성식†·김동진·이동복

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원자력발전소 2차측 습증기계통 주요지점별 부식 발생현황 분석
Pipes and components of the secondary system in the pressurized water reactor (PWR) are mainly comprised of manufactured carbon steel. Thus, the generated carbon steel corrosion products are transported into the steam generator and deposited, thereby deteriorating the integrity of the steam generator. Environmental
condition in the secondary system of the PWRs differs across different locations. So, the corrosion rate and types of corrosion products depend on specific locations in the secondary system. In this study, the quantity and chemical compositions of corrosion products generated in various locations that vary in different temperatures and chemistry conditions were investigated. As a result of evaluating the PWR “Unit A” that is in current operation, the amount of corrosion products generated in the section of high temperature feedwater system was identified as the largest source in the secondary system. Major components of corrosion products were iron oxides such as magnetite, hematite, and lepidocrocite.
KEYWORDs : Carbon steel, Corrosion products, Iron oxides, Magnetite, Hematite
AUTHORs : 이경희†· 한호석·신성용·성기방·이영우†

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Effects of NaCl Concentration and Solution Temperature on the Galvanic Corrosion Between CFRP and A516Gr.55 Carbon Steel
CFRP (Carbon Fiber Reinforced Plastics) is composed of carbon fiber and plastic resin, and is approximately 20 - 50% lighter than metallic materials. CFRP has a low density, higher specific stiffness, specific strength, and high corrosion resistance. Because of these excellent properties, which meet various regulation conditions
needed in the industrial fields, CFRP has been widely used in many industries including aviation and ship building. However, CFRP reveals water absorption in water immersion or high humidity environments, and water absorption occurs in an epoxy not carbon fiber, and can be facilitated by higher temperature. Since these properties can induce volume expansion inside CFRP and change the internal stress state and degrade the chemical bond between the fiber and the matrix, the mechanical properties including bond strength may be lowered. This study focused on the effects of NaCl concentration (0.01 - 1% NaCl) and solution temperature (30 - 75 oC) on the galvanic corrosion between CFRP and A516Gr.55 carbon steel. When
NaCl concentration increases 10 times, corrosion rate of a specimen was not affected, but that of galvanic coupled carbon steel increased by 46.9% average. However, when solution temperature increases 10 oC, average corrosion rate increased approximately 22%, regardless of single or galvanic coupled specimen.
KEYWORDs : CFRP, Carbon steel, Galvanic corrosion, NaCl concentration, Temperature
AUTHORs : Seung Young Hur, Ki Tae Kim, and Young Sik Kim†

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Corrosion Prediction of Metallic Cultural Heritage Assets by EIS
Electrochemical Impedance Spectroscopy (EIS) was used to predict corrosion behaviour of metallic Cultural Heritage assets in two monitoring campaigns: 1) an iron bar chain exposed indoor from over 500 years in the Notre Dame Cathedral in Amiens (France); and 2) a large weathering steel sculpture exposed outdoor from tens of years in Ferrara (Italy). The EIS portable instrument employed was battery operated. In situ EIS measurements on the iron chain could be used to investigate the phenomena involved in the electrochemical interfaces among various corrosion products and assess and predict their corrosion behaviour in different areas of the Cathedral. Meanwhile, the sculpture of weathering steel, like most outdoor artefacts, showed rust layers of different chemical composition and colour depending on the orientation of metal plates. The EIS monitoring campaign was carried out on different areas of the artefact surface, allowing assessment of their protective effectiveness. Results of EIS measurements evidenced how employing a simple test that could be performed in situ without damaging the artefacts surface is possible to quickly gain knowledge of the conservation state of an artefact and highlight potential danger conditions.
KEYWORDs : Electrochemical impedance spectroscopy (EIS), Cultural heritage, Weathering steels, Ancient iron, Atmospheric corrosion
AUTHORs : E. Angelini, S. Grassini, M. Parvis, and F. Zucchi

Page : 117 - 120 DOWNLOAD
A Research on Stray-Current Corrosion Mechanism of High Voltage Cable Connector on Electrification Vehicles
Considering the tendency of development of electrification vehicles, development and verification of new evaluation technology is needed because of new technology applications. Recently, as the battery package is set outdoors of an electric vehicle, such vehicles are exposed to corrosive environments. Among major components connected to the battery package, rust prevention of high-voltage cables and connectors is considered the most important issue. For example, if corrosion of high voltage cable connectors occurs, the corrosion durability assessment of using an electric vehicle will be different from general environmental corrosion phenomena. The purpose of this study is to investigate the corrosion mechanism of high voltage cable connectors of an electric vehicle under various driving environments (road surface vibration, corrosion environment, current conduction by stray current, etc.) and develop an optimal rust prevention solution. To improve our parts test method, we have proposed a realistic test method to reproduce actual electric vehicle corrosion issues based on the principle test.
KEYWORDs : Stray current corrosion, High voltage cable, Electrification vehicle, Fretting
AUTHORs : Hwi Yong Lee, Seung Ho Ahn†, and Hyun Taek Im

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