• Corrosion Science and Technology
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• v.20 no.1
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• pp.7-14
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• 2021

PosMAC^® is a brand of Zn-Mg-Al hot-dip coated steel sheet developed by POSCO. PosMAC^® can form dense surface oxides in corrosive environments, providing advanced corrosion resistance compared to traditional Zn coatings such as GI and GA. PosMAC^® 3.0 is available for construction and solar energy systems in severe outdoor environments. PosMAC^®1.5 has better surface quality. It is suitable for automotive and home appliances. Compared to GI and GA, PosMAC^® shows significantly less weight reduction due to corrosion, even with a lower coating thickness. Thin coating of PosMAC^® provides advanced quality and productivity in arc welding applications due to its less generation of Zn fume and spatters. In repeated friction tests, PosMAC^® showed lower surface friction coefficient than conventional coatings such as GA, GI, and lubricant film coated GA. Industrial demand for PosMAC^® steel is expected to increase in the near future due to benefits of anti-corrosion and robust application performance of PosMAC^® steel.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.201-206
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• 2002

The purpose of this study is to improve the anti-corrosive properties of coated reinforcing bar using polymer cement slurry. Poymer cement slurry are prepared with three types of polymer dispersions and corrosion inhibiting admixture. And tested for corrosion accelerating tests such as immersion in NaCl 10% solution NaCl 10% solution spray, high temperature and pressure steam in condition of 8cycles, carbonation before and after, penetration of NaCl solution. From the test results, it is concluded that the anti-corrosive properties are considerably improved by coating using polymer cement slurry at surface of reinforcing bar. And this trend is marked by adding of corrosion inhibiting admixture. The difference of the anti-corrosive properties is hardly recognized according to types of polymer dispersions. The anti-corrosive properties of coated reinforcing bar using polymer foment slurry are improved to a great extent compared to those of plain reinforcing bar accordiy to increasing content of chloride ion in cement concrete.

• Steel and Composite Structures
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• v.50 no.3
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• pp.363-374
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• 2024

The fatigue life of steel wire is affected not only by fatigue load, but also by corrosion environment in service period. Specially, the corrosion pit will lead to stress concentration on the surface of steel wire inducing the formation of fatigue cracks, and the fatigue cracks will accelerate the corrosion process. Therefore, the corrosion fatigue of steel wire is a coupling effect. In this study, the corrosion-fatigue coupling life curve is derived with considering corrosion-fatigue pitting stage, corrosion-fatigue short crack stage and corrosion-fatigue long crack stage. In addition, the stress concentration factors of different corrosion pits are calculated by COMSOL software. Furthermore, the effect of corrosion environment factors, that is, corrosion rate, corrosion pit morphology, frequency and action factor of fatigue load, on fatigue life of steel wire is analyzed. And then, the corrosion-fatigue coupling life curve is compared with the fatigue life curve and fatigue life curve with pre-corrosion. The result showed that the anti-fatigue performance of the steel wire with considering corrosion-fatigue coupling is 68.08% and 41.79% lower than fatigue life curve and fatigue life curve with pre-corrosion. Therefore, the corrosion-fatigue coupling effect should be considered in the design of steel wire.

• Corrosion Science and Technology
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• v.13 no.5
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• pp.195-203
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• 2014

Modern industry has a wide variety of application areas such as ocean industry, construction and automobile industry. With the current circumstances, the need for anti-corrosion technology that can be used on materials to withstand in harsh environments, is increasing. In this study, we have sought to develop a metal coating technology with zinc and aluminum powders as a potential anti-corrosion material. To make a coating on metal products, a thermal diffusion coating method was used under the conditions of $350^{\circ}C$ for 30 minutes. Optical microscope, Field emission scanning electron microscope (FE-SEM&EDX) and X-ray diffraction analysis were used to analyze a coating layer. As a result, we have confirmed that the generated amount of rust on metal parts coated with thermal diffusion coating method decreased dramatically compared with non-coated metal parts. Furthermore, the anti-corrosion performance was evaluated according to the different ratio of zinc and aluminum. Finally, we confirmed the possibility of application and commercialization of our coating technique on metal parts used in harsh industrial based on the results of these performance.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.11
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• pp.736-739
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• 2014

In this paper, we propose a enhanced anti-corrosion property of the ground system by coating the CNT/PVDF composite film on it. Polymer material used for preventing the corrosion of ground system is polyvinylidene fluoride (PVDF), and conducting filler for obtaining conductivity of the composite film is multi-walled carbon nanotubes (MWCNTs). The MWCNTs were dispersed in the organic solvent of methyl ethyl ketone 2-butanone (MEK) with different concentration ratios, and the PVDF was solved in the MEK solvent with constant concentration ratio of 1 wt%. The CNT/PVDF composite solution was perpared by mixing and re-dispersing the CNT solution and the PVDF solution. Finally, the CNT/PVDF composite films were fabricated by the spray coating method using the above composite solution. Electrical conductivity, surface states, and anti-corrosion property of the CNT/PVDF composite films coated on the Cu substrate were evaluated. We found that the CNT/PVDF composite film showed relatively low resistance, hydrophobic surface state, and chemical stability. Consequently, we could improve the anti-corrosion property and maintain the electrical conductivity of the ground system by coating the CNT/PVDF composite film on it.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.232-233
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• 2014

Recently, water treatment facility is usually eastablished in underground, and waterproofing and anti-corrosion materials for concrete structures applied water treatment tank is developing in various ways. However, as the limit of research focused on durability improvement of top coating material, it is insufficient to study on the adhesion strength between the concrete surface and primer. Therefore, there is to confirm the adhesion of between concrete surface and the three primers used as anti-corrosion waterproofing materials, and to investigate the properties of adhesion strength according to the condition such as wet codition and water pressure condition of the concrete surface in this study.

• Corrosion Science and Technology
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• v.12 no.5
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• pp.209-214
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• 2013

In the industry, accelerated corrosion test is used for the life time prediction. When anti-corrosion test proceeds in real environments, it is difficult that we predict and evaluate the corrosion life time because of the long test time such as 10 years or more time. Accelerated corrosion test and Salt spray test are able to test corrosion life time of products in the laboratory instead of outdoor corrosion test. Experimental procedure is selected for the corrosion standard specimen, exposure of the specimens, measurements of the mass loss and evaluating the mass loss data. As a result, the acceleration factor of the accelerated corrosion test to the outdoor corrosion test is 414.8. Therefore we can predict the corrosion life time of carbon steel during a short time period.

• Journal of the Korean Society for Heat Treatment
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• v.16 no.6
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• pp.335-340
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• 2003

To improve properties of wear resistance and anti-corrosion of the trivalent chromium platings, oxinitrocarbunsing and steam oxidation were conducted. Armophous trivalent Cr platings could be transformed to chromium carbides of high hardness, that showed low friction and wear rate. Even though micro-cracks were within as platings, superior anti-corrosion property was obtained by these treatments due to healing of cracks at the interface between the trivalent chromium platings and substrate.

• Corrosion Science and Technology
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• v.18 no.6
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• pp.228-231
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• 2019

Aluminum and its alloys have been widely used in various fields because of low weight, high strength, good conductivity, and low price. It is well known that aluminum alloys that cause natural oxide film can inhibit corrosion in wet, salty environments. However, these oxides are so thin that corrosion occurs in a variety of environments. To prevent this problem, an electrochemical anodizing technique was applied to the aluminum alloy surface to form a thick layer of oxide and a unique oxide shape, such as a hierarchical pore structure simultaneously combining large and small pores. The shape of the structures was implemented using stepwise anodization voltages such as 40 V for mild anodizing and 80 V for hard anodizing, respectively. To maximize water repellency, it is crucial to the role of surface structures shape. And a hydrophobic thin film was coated by 1H, 1H, 2H, 2H-Perfluorodecyltrichlorosilane (FDTS) to minimize surface energy of the structure surface. Thus, such nanoengineered superhydrophobic surface exhibited a high water contact angle and excellent corrosion resistance such as low corrosion current density and inhibition efficiency.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.359-364
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• 2001

The purpose of this study is to develop the repair system for RC members with damaged by rebar corrosion using new corrosion inhibitor which was high nitrite content. In the experiments, the acceleration corrosion test of rebar was conducted using the specimen which was applied by various repair system. As a result, it was confirmed that the new repair system without concrete patching had high anti-corrosion property compared with other repair systems and was very effective as a spray type corrosion inhibitor in concrete containing chloride (0.1% of NaCl).