• Journal of Hydrogen and New Energy
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• v.20 no.6
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• pp.534-539
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• 2009

One of the most efficient techniques improving the heat transfer performance of a diesel electric generation is a corrosion control in jacket cooling water system. The environmental parameters most affecting corrosion are dissolved salt concentration, temperature, and pH of cooling water. No corrosion occurs in carbon steel probe at pH 11 in normal operating condition of diesel electric generation cooling water. pH control agent in this study is trisodium phosphate. pH control appears to be the most convenient way to enhance the thermal performance of a diesel electric generation.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.177-178
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• 2015

Recently, Advanced water treatment facilities with Ozone are being introduced owing to domestic water pollution. However, waterproofing/corrosion prevention construction method of concrete structure for existing advanced water treatment makes waterproofing/corrosion prevention materials and concrete deteriorated because of strong oxidation of ozone. it causes increase of maintenance cost and water quality degradation. Therefore, in this study, it will figure out problems of waterproofing/corrosion prevention construction method being applied to through existing studies.

• Corrosion Science and Technology
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• v.12 no.3
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• pp.149-157
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• 2013

In corrosion-sensitive areas of exsisting unpainted weathering steel bridges with closed box girder structures. there are some serious local corrosion problems because of rain water or dew water which can not be solved by exsisting maintenance methods. These problems must be controled technically because of bad. influence on the safety of bridge. This study is the first stage of developing the economic corrosion control manual for these local corrosion problems. Through the injection of tar sealant into the crevice of mock-up equipment, it was prooved that the corrosive sealant can be useful to corrosion control at crevice of corrosion sensitive area.

• Corrosion Science and Technology
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• v.19 no.6
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• pp.296-301
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• 2020

Failure analysis on the welded type 304 pipe used for cooling water piping in the district heating primary side was conducted. Inorganic elements and bacteria in the cooling water and in corrosion products were analyzed, and the weldment was inspected by microscopy and a sensitization test. Corrosion damages were observed in the heat-affected zone, on weld defects such as incomplete fusion or excessive penetration caused by improper welding, or/and at the 6 o'clock position along the pipe axial direction. However, the level of concentration of chloride in the cooling water as low as 80 ppm has been reported to be not enough for even a sensitized type 304 steel, meaning that the additional corrosive factor was required for these corrosion damages. The factor leading to these corrosion damages was drawn to be the metabolisms of the types of bacteria, which is proved by the detection of proton, sulfur containing species, biofilms, and both bacteria and corrosion product analyses.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4117-4123
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• 2013

In the present study, coating corrosion characteristics of the heat exchanger for sea water are experimentally investigated. Coating types by a teflon, an electrodeposition and a ceramic+silicon were tested and compared with the corrosion characteristics of an aluminum. For the acceleration of corrosion by sea water, the temperature of sea water $70^{\circ}C$ and the concentration of salt 3.5% were considered. And the specimens were immersed in sea water during 9 weeks. Coating corrosion characteristics were measured by using the impedance method and SEM. Experimental results showed that polarization resistances obtained from Bode plot were related to the corrosion resistance of coating types, and the corrosion resistance of double coating were maintained during 4 weeks. From SEM photograph, we saw that blisters was generated on the interface between metal and coating.

• Nuclear Engineering and Technology
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• v.56 no.10
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• pp.4404-4411
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• 2024

The dissolved oxygen in a coolant can affect the oxidation properties of structural materials. A desirable oxide phase formation is achieved by manipulating the oxygen level in the coolant, which can mitigate structural material degradation in nuclear power plants. Therefore, the role of dissolved oxygen in the corrosion of structural materials in aqueous environments needs to be understood. In this study, a short-term corrosion test (up to 300 h) of Ferritic/Martensitic steels (F/M steels; FeCrW model alloys), namely, Fe12Cr1W, Fe9Cr1W, and Fe9Cr, in stagnant water at 360 ℃ was performed in a pressurized autoclave with the dissolved oxygen concentration controlled to 1 ppm or a very low level (<1 ppm). The results of the corrosion tests showed that an increase in the oxygen level in the water elevated the corrosion potential, allowing the phase transition of iron oxide from magnetite (Fe₃O₄) to hematite (Fe₂O₃), whereas there was no significant correlation between the concentrations of the alloying elements Cr and W and the oxide growth rate. In addition, hematite was found to mitigate further oxide growth. Finally, a mechanism for the growth of the initial oxide layer was proposed based on the experimental results.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.2
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• pp.228-237
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• 2005

The main purpose of this study was to investigate the red water reducing effects of phosphate based inhibitor when it was applied to water distribution system. The effects of pH, alkalinity, calcium concentration in the reduction of the red water also studied. The most finished water in Korea showed relatively high corrosiveness and was required to introduce some types of corrosion reducing methods such as addition of alkalinity. The precipitation of $CaCO_3$ by addition of $Ca(OH)_2$ formed porous film on the surface of the carbon steel pipes and was displaced easily from the surface of the pipes; on the other hand, addition of zinc phosphate (ZOP) formed reliable film on the surface and reduced iron release and color. Although the main function of ZOP was to suppress the release of Pb and Cu, it also reduced iron concentration released from water distribution pipes.

• Corrosion Science and Technology
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• v.19 no.4
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• pp.196-202
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• 2020

The air vent connected to a heat supply pipeline in the district heating system has been used to eliminate the existing air in the pipe, which has a detrimental effect on corrosion durability and heat efficiency. Recently, the air vent installed under a manhole for 22 years was corroded and several pinholes were detected in the front-end of the air vent. To identify the cause of the failure, thickness reduction, corrosion products, and water quality were examined. The corrosion damage was significant at the outside of the front-end of the air vent where the insulator was covered. While a thin oxide layer was formed in the interior of the tube, the coarse and porous corrosion products consisting of magnetite and hematite were found externally. Water flowing into the thermal insulator was absorbed by the insulator following hydrolysis. The hydrolyzed insulator ejected the corrosion factors such as Cl^-, SO₄^2-, and NH₄⁺. The findings suggest that the corrosion under insulation due to rain water is the main cause of the underlying failure in the air vent.

• Journal of environmental and Sanitary engineering
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• v.7 no.1
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• pp.1-16
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• 1992

Corrosion of pipes Is one of the most serious problems in the maintenance of water worlds. Corrosion is promoted not only by physical factors such as temperature, but also by electrochemical factors including concentration of soluble metal ions, chlorine ion, pH, DO and microorganisms. Corrosion products also affect corrosion rate. In this research, study results are summarized as follows ; 1) Corrosion test was performed for 4 weeks at $70^{\circ}C$, pH 7.0 with specimens of 4 types of metal materials used as service pipes. Corrosion rate and S.E.M were analyzed. The results were showed that corrosion 1.ate of carbon steel pipe was 4.10~5.22 $mg/\textrm{cm}^2$ . week, galvanized steel pipe 0.98~1.34$mg/\textrm{cm}^2$. week, Copper pipe 0.02~0.04$mg/\textrm{cm}^2$. week, stainless steel pipe 0.05~ 0.10$mg/\textrm{cm}^2$ . week. 2) When corrosion rate was tested for tile types of pipes at pH 7 and both $25^{\circ}C$ and $75^{\circ}C$, avaerage corrosion rate for 6 weeks at $25^{\circ}C$ Ivas 2.26$mg/\textrm{cm}^2$ . week in carbon steel pipe, 1.99$mg/\textrm{cm}^2$. week in galvanized steel pipe, 0.26 $mg/\textrm{cm}^2$. week in stainless steel pipe. At $87^{\circ}C$, average corrosion rate for 4 weeks u.3s 4.56 $mg/\textrm{cm}^2$. week in carbon steel pipe,

• Corrosion Science and Technology
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• v.21 no.5
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• pp.390-411
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• 2022

Any design engineer or coating formulator's primary objective is to protect metals. Large investments in terms of money, time, labour, and other resources are necessary for constructing large-scale machinery and structures. In terms of economy, the structure's lifespan should be as long as feasible to create revenue. It is becoming essential to protect metal substrates from corrosion to prolong the lifespan of such huge structures. One of the most exciting, durable, useful, and effective methods to protect metals from corrosion is the application of corrosion-resistant coating. Graphene is a novel material with a wide range of applications because of its extraordinary features. The use of graphene in coating creates an obstacle and complicates the path for corrosive medium to reach the metal. As the path to the metal elongates, the corrosion medium takes longer to reach the metal. Thus, metal corrosion can be avoided. In this paper, the importance of graphene in coating formulation is discussed, including chemical modifications of graphene, the effect of graphene concentration on corrosion inhibition, and the contact angle of coating. This review also highlights the significance of water-based corrosion-resistant coating for preventing environmental damage.