• Journal of Ocean Engineering and Technology
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• v.2 no.2
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• pp.87-95
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• 1988

This paper is studied to know corrowive wear characteristics of austempered ductile cast ironin corrosive environments against mating SM45C hardened two test pieces in distilled water and NaCl aqueous solution. The corrosive wear mechanism was investigated by scanning electron microscopy and retained austenite volume fraction was investigated by X-ray diffractometer. The experimental result show that the corrosive wear characteristics depend largely on the $\textrm{Fe(OH)}_{3}$which is influenced by the critical sliding distance $L_{cr}$ and $L_{cr}$ shorted with increasing NaCl concentration. It was found that the carbides in matrix have a significant effect on their corrosive wear resisance and the fine acicular bainite showed corrosive wear resistance stronger than that of the coarse acicular and platelet bainite. From above results the model of corrosive wear mechanism in corrosive environments is proposed.

• Corrosion Science and Technology
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• v.8 no.6
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• pp.238-242
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• 2009

Corrosion of metallic materials occurs by the reaction with corrosive environment. In general, corrosive environments are classified as atmospheric, marine, soil etc. and regardless of any corrosive environments, reduction of thickness and cracking and degradation are induced by corrosion. Among several corrosive environments, knowing the atmospheric corrosiveness of a region, city, or country is considered of ultimate importance for major industrialists and investors who require knowledge of the corrosive impact of the atmosphere on everyday materials such as carbon steel, weathering steel, zinc, copper, and aluminium. This is why the atmospheric corrosiveness map is needed. This paper dealt with corrosion properties between several waters in the region and carbon steel, weathering steel, galvanized steel, pure copper, and pure aluminium at the representative rural area of Korea - Andong.

• Journal of the Korean Society for Railway
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• v.4 no.2
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• pp.62-70
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• 2001

Pure copper, Cu-1.1wt%Cd and ACSR(Aluminum Conductor Steel Reinforced) have been used as catenary materials of the electric railway system. Since these materials may be exposed to the corrosive environments like polluted air, acid rain and sea water, it is important to investigate the corrosion rates in various corrosive environments. The aqueous corrosion characteristics of catenary materials in aerated acid, neutral and alkali solutions were studied by using immersion corrosion tests, electrochemical measurements and analytical techniques. In order to examine corrosion characteristics according to the dissolved oxygen content, pH, chloride ion concentration ion, and the addition of Cd to Cu, a series of tests such as potentiodynamic polarization, a.c impedance spectroscopy and galvanic corrosion tests were carried out with these materials. Results showed that the addition of Cd to Cu and chloride ion in the solution have an adverse effects on the resistance to corrosion. Additionally, Galvanic currents between Al and steel wires of ACSR were confirmed by using ZRA(zero resistance ammeter) method.

• Journal of the Korean Ceramic Society
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• v.27 no.2
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• pp.161-168
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• 1990

To evaluate the corrosion behavior of reaction bonded silicon carbides, corrosion test was studied for various corrosive environments. Corrosion test for reaction bonded silicon carbides was conducted at 900$^{\circ}C$ under four different gas atmospehres ; air, So2-air, Cl2-O2-Ar, Cl2-N2 and investigated these samples using weight loss, bending strength, XRD, optical micrographs and EDS respectively.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.6
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• pp.1404-1411
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• 1993

This study was undertaken to investigate the corrosive wear charateristics upon various transformation condition of austempered low-alloy ductile cast iron in corrosive environments against mating specimen made of the hardened SM45C. The corrosive wear test was carried out by rubbing the annular surface of two test pieces in distilled water and aqueous solution at constant sliding speed of 0.5m/s. In severe wear region, the corrosive wear rate Wc increased hastily with NaCl concentration owing to intermetallic adhesion but Wc went down slowly in mild wear region due to lubricating effect of the corrosion product. The critical sliding distance decreased with increasing NaCl concentration due to increased generation rate of the corrosion product and the specific corrosive wear rate has maximum in 1% NaCl aqueous solution at mild wear region. With the variation of matrix, the corrosive wear resistance of the fine acicular bainite was higher than that of coarse upper bainite because of reducing the local cell reaction by carbides. A growth in volume fraction of retained austenite in matrix increased the Wc due to soften surface, but has a declining tendency of Wc in mild wear region.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.680-685
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• 2004

The effects of acid rain and salt content on corrosion behavior were investigated with rolling stock structural steels be caused by environmental. Since these materials are exposed to the corrosive environments like polluted air, acid rain and sea water, it is important to investigate corrosion behaviour in various corrosive environments. The aqueous corrosion of the characteristic materials in aerated acid rain and neutral solution were studied by using immersion tests, electrochemical measurements and analytical techniques. In order to examine corrosion characteristic, structural steels were electrochemically evaluated with respect to the dissolved oxygen content, pH, chloride ion concentration.

• Journal of the Korean Society for Railway
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• v.5 no.1
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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.

• Magazine of the Korea Concrete Institute
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• v.11 no.2
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• pp.251-259
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• 1999

Recently, large scale concrete structures exposed to severe environments are increasingly built in various locations, The corrosion may severely affect the durability and service life of such a concrete structure. It is, therefore, necessary to develop a method to enhance the corrosion resistance of a concrete, The purpose of this paper is, therefore, to investigate the corrosion resistance and bond strength characteristics of anti-corrosive cement coated reinforcements. To this end, a comprehensive experimental study has been done to explore the corrosion and bond behavior of those coated reinforcements. The test results indicate that the anti-corrosive cement coated reinforcements do not exhibit any corrosion after corrosion tests and the bond strengths are very good as much as plain bar. It is seen that the anti-corrosive cement coated reinforcements can be efficiently used to enhance the durability of reinforced concrete structures.

• Journal of the Korean institute of surface engineering
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• v.32 no.3
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• pp.195-207
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• 1999

The use of multilayered electrodeposits, to enhance coating performance especially in corrosive environments, has uncertain origins but has been systematically practiced and optimized since the 1950s. The background to such systems will be traced, examples given of their usage, and the recent development of nanometre multilayers by pulsed plating techniques described.

• Journal of the Korean institute of surface engineering
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• v.51 no.2
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• pp.95-103
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• 2018

Recently, many types of constructional steels have been often exposed to under severe corrosive environments due to acid rain with increasing environmental contamination. In order to inhibit their corrosion in severe corrosive environments, a painting method has been widely applied to numerous constructional steels of land as well as marine. Therefore, development of paint having a good quality of corrosion resistance is considered to be very important. In this study, four types of anti-corrosive paints (AP: Phenol epoxy, AC: Ceramic epoxy, AT: Coal tar epoxy, AH: High solid epoxy) were coated to the specimens, and then, were immerged in various salt solutions (0.1, 0.3, 3, 6, 9 and 15% NaCl solutions) for 11 days. And, the corrosion resistance of these samples by effect of osmotic pressure with salt concentration was investigated with electrochemical methods such as measurement of corrosion potential, impedance and corrosion current density. The corrosion current densities of all samples (AC, AT and AH) submerged in 3% NaCl solution exhibited the smallest values compared to other salt solutions. However, in the case of lower values of salt solutions than 3% NaCl solution, the corrosion current density increased again because it makes easier for water, dissolved oxygen and chloride ion etc. to invade toward inner side of coating film due to increasing of the osmotic pressure than 3% NaCl solution, but in the case of higher values of salt solutions than 3% NaCl solution, the coating film is easily deteriorated due to high concentration of chloride ion rather than the osmotic pressure, which resulted in increasing the corrosion current density. In particular, the AC sample indicated the best corrosion resistance in 6% NaCl solution compared to other samples. Consequently, it is considered that the corrosion mechanism of the coated steel plate is completely different from bare steel plate, and the corrosion resistance of coating film by osmotic pressure and chloride ion depend on various types of epoxy of paint in NaCl solution.