• Corrosion Science and Technology
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• 제22권5호
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• pp.305-313
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• 2023

The objective of this study was to investigate the effectiveness of sodium dodecyl benzene sulfonate (SDBS) as a corrosion inhibitor on the pitting corrosion behavior of aluminum alloys used in electric vehicle battery cooling systems within a mixture of ethylene glycol and water (EG-W) coolant. Potentiodynamic polarization testing revealed unstable passive film formation on the aluminum alloys in the absence of SDBS. However, the addition of SDBS resulted in a robust passive film, enhancing the pitting corrosion resistance across all examined alloys. Pitting corrosion was predominantly observed near intermetallic compounds in the presence of Cl? ions, which was attributed to galvanic interactions. Among tested alloys, A1040 demonstrated superior resistance due to its lower areal fraction of precipitates and donor density. The incorporation of SDBS inhibitors mitigated the overall pitting corrosion process by hindering Cl? ion penetration. These findings suggest that SDBS can significantly improve pitting corrosion resistance in aluminum alloys employed in battery coolant environments.

• 대한기계학회논문집A
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• 제21권9호
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• pp.1422-1431
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• 1997

When the structures are exposed to their own an application for a long period, a number of variables such as strength properties and corrosion resistance, so on are expected to change. In the present investigation the corrosion behavior and resistance for the original and degraded materials of Ni-Cr-Mo-V steel were evaluated under the conditions of pH 3, 6, 9 and 12 in a distilled water environment. The electrochemical polarization technique was employed in this investigation. Based upon the experimental results obtained, the following conclusions were drawn. A severe and uniform corrosion was observed for both original and degraded materials under the condition of pH 3. At pH 6 and pH 9, these materials showed the degradation by a pitting corrosion. The materials under pH 12 environment were degraded by a uniform corrosion. The corrosion rate per year were the highest in the pH 3 environment, followed by pH 12, pH 6 and pH 9 environment in order. The corrosion resistance was decreased from the original material, slow cooled material (10.deg. C/hr) and step cooled material in order.

• Corrosion Science and Technology
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• 제7권6호
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• pp.324-327
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• 2008

Stainless steels have been widely used as a building exterior materials in Asian countries for the last decade. It is required for the materials in this field to have an aesthetic appearance, a relatively high strength, and an excellent corrosion resistance. Other metallic materials such as copper, aluminum, and carbon steels have been also used as the exterior materials. Considering the cost of maintenance, stainless steel, having the outstanding corrosion resistance, is replacing other materials in the several parts in the building exteriors. Ferritic stainless steel has been applied as the roofing materials because its thermal expansion is much smaller than that of austenitic stainless steel. Therefore, it is suitable for the large-scale construction such as airport terminal, convention center, and football stadium. To improve the corrosion resistance of the ferritic stainless steels, the modification of alloy composition has been studied to develop new grade materials and the progress in the surface technology has been introduced. Corrosion properties of these materials were evaluated in the laboratory and in the field for longer than two years. High-Cr ferritic stainless steel showed excellent corrosion resistance to the atmospheric environments. In the region close to the sea, the corrosion resistance of high-Cr ferritic stainless steel was much superior to that of other materials, which may prove this steel to be the appropriate materials for the construction around seashore. In some of the large constructions around seashore in South Korea, high-Cr ferritic stainless steels have been used as the building exterior materials for six years.

• Corrosion Science and Technology
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• 제20권4호
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• pp.196-203
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• 2021

To improve corrosion resistance and reduce the hydrogen uptake of 22MnB5, up to 5% Mg was added to the AlSi coating of 22MnB5. After hot-stamping and electrocoating were done on the metallic-coated specimen, the surface characteristics of the steel, hydrogen uptake content, and corrosion resistance were examined by transmittance electron microscopy, thermal desorption spectrometry, cyclic corrosion testing, and electrochemical impedance spectroscopy. Mg was investigated as MgO on the surface layer after hot-stamping while it existed as Mg₂Si before hot-stamping. The total hydrogen content of 22MnB5 was decreased along with the Mg content. However, there was no difference at 0.2 wt% or more. When a small amount of Mg was added, the coating corrosion resistance was decreased, but when it was added at around 1.0 wt%, the greatest corrosion resistance increase was seen. However, when 3 wt% or more was added excessively, the corrosion resistance was decreased. MgO on the surface was considered to suppress H uptake by the AlSi melting solution and increase the barrier effect of the coating.

• Corrosion Science and Technology
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• 제20권3호
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• pp.152-157
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• 2021

Stainless steel is a metal that does not generate rust. Due to its excellent workability, economic feasibility, and corrosion resistance, it is used in various industrial fields such as ships, piping, nuclear power, and machinery. However, stainless steel is vulnerable to corrosion in harsh environments. To solve this problem, its corrosion resistance could be improved by electrochemically forming an anodized film on its surface. In this study, 316L stainless steel was anodized at room temperature with ethylene glycol-based 0.1 M NH₄F and 0.1M H₂O electrolyte to adjust the thickness of the oxide film using different anodic oxidation voltages (30 V, 50 V, and 70 V) with time control. The anodic oxidation experiment was performed by increasing the time from 1 hour to 7 hours at 2-hour intervals. Corrosion resistance according to the thickness of the anodic oxide film was observed. Electrochemical corrosion behavior of oxide films was investigated through polarization experiments.

• 한국표면공학회지
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• 제36권5호
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• pp.398-405
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• 2003

The stainless steel wire requires good corrosion resistance and mechanical properties, such as drawing ability, combined with a high resistance to corrosion. For increasing drawing ability of stainless steel, Ni coating methods have been used in this study. However, there is no information on the electrochemical corrosion behavior of drawed wires after Ni coating. To investigate corrosion resistance and mechanical property of drawed wire, the characteristics of Ni coated wires have been determined by tensile strength tester, hardness tester, field emission scanning microscope, energy dispersive x-ray analysis and potentiodynamic method in 0.1 M HCl. The drawed stainless steel wires showed the strain-induced martensitic structure, whereas non-drawed stainless steel wire showed annealing twin in the matrix of austenitic structure. The hardness and tensile strength of drawed stainless steel wire were higer than that of non-drawed stainless steel wire. Electrochemical measurements showed that, in the case of drawed stainless steel o ire after Ni coating, the corrosion resistance and pitting potential increased compared with non-coated and drawed stainless steel wire due to decrease in the surface roughness.

• 한국표면공학회지
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• 제45권4호
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• pp.162-167
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• 2012

Ni-P/C multi-layer was synthesized by electroless plating and paste coating for better corrosion and surface conductance as a metallic bipolar plate. The Ni-P layer could be synthesized with the range of 2.6~22.4 at.% P contents and it's surface morphology and corrosion resistance depend on content of P. Corrosion resistance of the Ni-P layer in sulfuric acid by electrochemical test is similar with pure Ni. Surface resistance of pure Ni after corrosion was increased about 8% compared to pure Ni. On the other hand, that of the Ni-P/C composite with 20% carbon content was increased only 1%.

• 소성∙가공
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• 제28권2호
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• pp.77-82
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• 2019

Corrosion occurs well on surface of roll formed and Zn alloy subsequently electro-deposited on steel bolt under wet condition. In this study, variations in corrosion resistance were investigated through the measurement of polarization curves on steel bolts which were roll formed and subsequently coated with various types of coating methods. According to the measured polarization curve, Ni-P electroless deposits on roll formed steel increased the resistance to corrosion. The corrosion resistance of Zn alloy powder coated steel bolt was found to be better than that of Zn-Ni electro-deposited sample.

• Corrosion Science and Technology
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• 제5권3호
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• pp.112-116
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• 2006

This study has been conducted to monitor the corrosion rate of cathodically protected structure and corrosion inhibited system using multi-line thin-film electrical resistance (TFER) sensor in various environments. The field test data of TFER sensor for the corrosion monitoring of cathodically protected underground pipeline in soil environments and of corrosion inhibited gas heaters were also presented. The sensor was found to be a powerful method to commit the sensitive pick-up of small corrosion rate which can be observed in the cathodically protected and corrosion inhibited systems.

• 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.