• Proceedings of the Korea Concrete Institute Conference
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• 1998.10c
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• pp.223-228
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• 1998

This study is to investigate on the remaining life of reinforced concrete apartment by using the probability of a reinforcing-steel corrosion and the carbonation tendency of domestic reinforced concrete apartments by using the statistic method. The results are as follow. ·To compare with the carbonation velocity of Kishitani's formula (x=3.727{{{{ SQRT { t} }}) when water-cement ratio is w=0.6, R=1, it is founded out that the carbonation velocity is slow a little in all area investigated and inland area, and fast a bit in coastal area. ·In the influencing factors in regard to the probability of reinforcing-steel corrosion, It seems that the influence of elapsed time is more effective than that of region. Therefore, it is necessary that it makes sure of the cover depth under apartment construction in recent so far as the durability is considered.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.1193-1198
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• 2001

The glass of Ground Granulated Blast Furnace Slag(GGBFS) was released by the hydroxyl ions during the hydration of the Portland cement. That results in relatively less $Ca(OH)_{2}$ in the concrete replaced with GGBFS than in ordinary portland cement concrete(OPCC). As the quantity of $Ca(OH)_{2}$ is decreased, the rate of carbonation in the concrete replaced GGBFS is faster than OPCC. Therefore, it has been misunderstood that the concrete replaced GGBFS has negative effect on the corrosion of steel by carbonation. Therefore, this study aimed at the relation between carbonation and rebar corrsion in the concrete with GGBFS, measuring air.water permeability, half cell, and corrosion rate by the depth of carbonation.

• New & Renewable Energy
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• v.3 no.1 s.9
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• pp.75-82
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• 2007

Aluminum was used as metallic bipolar plate material to reduce a stack weight. The functional materials such as conductive material, Au and nonconductive material, PTFE [polytetrafluoroethylene] were coated on the bipolar plate to enhance electrical contact and corrosion prevention in PEMFC. The active area of bipolar plate is divided into the top layer part that electric current mainly passes, and the bottom layer part that gas and water pass. The bottom layer part in the flow channel needs not to have electrical conductivity because it doesn't pass electric current directly. In this reason, Au on the top layer and PTFE on the bottom layer were coated to apply high electrical conductivity and/or good corrosion resistance. Although the single cell performance using Au-PTFE/Al bipolar plate was shown 78% in comparison with that of graphite, specific power of Au-PTFE/Al bipolar plate(0.4 W/g) was twice as much as graphite bipolar plate.

• Journal of the Korean Society of Safety
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• v.23 no.4
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• pp.59-66
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• 2008

Recently, the deterioration of reinforced concrete structures, primarily due to corrosion of steel reinforcement, has become a major concern. Chloride-induced deterioration is the most important deterioration phenomenon in reinforced concrete structures in harsh environments. For the realistic prediction of chloride penetration into concrete, a mathematical model was developed in which the effects of diffusion, chloride binding and convection due to water movement can be taken into account. The aim of this research was to reach a better understanding on the physical mechanisms underlying the deterioration process of reinforced concrete associated with chloride-induced corrosion and to propose a reliable method for estimating these effects. Chloride concentrations coming from de-icing salts are significantly influenced by the exposure conditions such as salt usage, ambient temperature and repeated wet-dry cycles.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.789-792
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• 1999

Reinforced concrete structures covered creek for road vehicle located in urban areas have been experiencing corrosion of concrete and reinforcing steel caused by $H_2S$ gases generated by anaerobic bacterial. H2S gases react with oxygen and water to form sulfuric acid ($H_2SO_4$). This acid chemically attacks concrete, and sulfate ions penetrate into the concrete, causing rebar corrosion. In this work, to determine the conditions of RC culvert boxes which were constructed in the 1970s, various tests were conducted, including carbonation depth, compressive strength, half-cell potential measurements, and XRD analyses. Results indicated that the concrete deterioration was caused by sulfate attack and rebar corrosion. This paper discusses the evaluation on the durability of reinforced concrete structures covered creek for road vehicle.

• Journal of Surface Science and Engineering
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• v.49 no.5
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• pp.395-400
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• 2016

This article reports improved corrosion resistance and adhesion of electro-paint (E-paint) with fluoride conversion coating (FCC) on AZ31 Mg alloy for the first time. These improvements were observed in comparison to chemically polished samples with no chemical conversion coating and samples with cerium conversion coatings (CeCC). FCCs were prepared in a hydrofluoric acid (HF) solution for four different times; 10, 30, 60, and 120 s. The colour of the samples changed from light gold to brown with increasing immersion time, indicating the formation of thicker FCC coatings with increasing immersion time. The adhesion of the E-paint on FCC-coated AZ31 Mg alloy was tested after 500 h of immersion in deionized (DI) water. Salt spray test (SST) results revealed delamination of E-paint on the chemically polished sample, severe blistering on the samples with CeCC, but no delamination and no blistering on the samples with FCC.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.189-189
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• 2015

In this study, the corrosion resistance and adhesion of electrophoretic paint (E-paint) were studied on AZ31 magnesium alloy pretreated in cerium chemical conversion coating solutions with the addition of various ethanol concentrations. It was found that with increasing ethanol concentration from 0 to 90 percent can decrease the formation of $Mg(OH)_2/MgO$ and increase the formation of nano-crystalline cerium oxides on the coating. Both corrosion resistance and adhesion of E-painted AZ31 increased with increasing ethanol concentration. The best E-paint sample was observed on the sample pretreatment in cerium chemical conversion coating solution with the addition of 80 percent of ethanol. This sample showed an excellent adhesion without paint detached after water immersion test for 500 h at $40^{\circ}C$, and only a few blisters observed at the near scratched sites after 1000 h salt-spray test.

• Journal of the Korea Safety Management & Science
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• v.2 no.3
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• pp.197-210
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• 2000

In this paper, sensor ring for antilock brake system was studied using the 400 series ferrite stainless steel powder. Because of more excellent corrosion resistance and mechanical characteristics than iron, sensor ring has been manufactured by P/M(Powder Metallurgy) method 400 series ferrite stainless steel. the results are following. 1, Compared with sensor ring made by iron, 400 series ferrite stainless steel has shown a good corrosion resistance without an addition surface treatment. thus the decreasing production process has been obtained. 2. The products before sintering are much more corrodible in the condition of spray test of salt water and ammonia than humidity and nitrogen condition.

• Journal of Ocean Engineering and Technology
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• v.29 no.6
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• pp.475-480
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• 2015

In this study, we developed a Cr-free organic/inorganic hybrid solution and investigated its coating properties on degraded STS316L. Both the OIBD-1 solution and OIBD-2 solution had excellent corrosion resistance and adhesion ability. However, the solution had some problems in a boiling water environment. In addition, the flexibility was excellent, and the scratch resistance was relatively good.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.488-490
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• 2003

As aluminum becomes more widely used in power distribution systems, so the corrosion caused by bimetallic contacts of aluminum and copper becomes more serious problem. In particular, the poor contact of the commonly used compression type bimetal connections may bring about the disastrous interruption of the power supply resulted from the increased corrosion within the joints, which is accelerated by the permeation of water and electrolyte into the interface. In this paper, the corrosion characteristics of aluminum and copper are investigated to improve the reliability of Al-Cu connectons.