• Corrosion Science and Technology
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• v.17 no.1
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• pp.6-11
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• 2018

Outdoor exposure tests using of 7B04 aluminium alloy samples including plate, tensile and various SCC samples were carried out in Tuandao station, Shandong province (East of China) and Wanning station, Hainan province (South of China). Corrosion characteristics including weight loss, microstructure, tensile strength and SCC susceptibility were investigated. The corrosion rates in Tuandao and Wanning showed high to low and the corrosion rates changed to the following equation of $w=at^b$ (b<1). The corrosion of 7B04 aluminium alloy in Wanning was more serious than that in Tuandao. Pitting appeared at early stage of expose test, and it can be changed to general corrosion with test time extension. The 7B04 aluminium alloy of which specimen shapes are forging and thick plate also showed SCC (Stress corrosion cracking) in the marine atmosphere. The higher SCC sensitivity was observed in Wanning station than in Tuandao station. The 7B04 aluminium alloy with a high stress level was more sensitive to SCC. Intergranular and transgranular or a mixed mode of cracking can be observed in different marine exposure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.162-165
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• 2003

The corrosion characteristics of diffusion barrier in Copper CMP has been investigated. Key experimental variables that has been investigated are the corrosion rate by different agents containing slurry of Cu CMP. Whenever Cu and Ta films were corroded adding each oxidizer, the corrosion rate of Ta was much lower than that of Cu. That is, the difference in the corrosion rates of Ta by oxidizer was not larger as compared with Cu. As corroded by complexing agents, the corrosion rate of Ta was close to O. The corrosion rate of Ta increased as added $HNO_3$ and $CH_3COOH$ compared with the reference slurry; on the other hand, it decreased with addition of HF. In addition, resulting corrosion rate went up with lower pH of agent. The corrosion rates by agents were however significant small; hence, it doesn't affect on the removal rate of Cu CMP practically. Consequently, this can be explained by assuming that the mechanical effect dominates than the chemical effect on the polishing rate of Ta(TaN).

• Corrosion Science and Technology
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• v.15 no.2
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• pp.43-53
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• 2016

In this study, electrochemical impedance spectroscopy (EIS) was used to examine the changes in the electrochemical properties of biodegradable pure magnesium implanted into Sprague-Dawley rats for three days. The in vivo test results were compared with those of the in vitro tests carried out in Hank's, dilute saline and simulated body fluid (SBF) solutions. The in vitro corrosion rates were 20~1700 fold higher, as compared to the in vivo corrosion rates. This discrepancy is caused by biomolecule adsorption on the surface, which prevents the transport of water into the magnesium surface on in vivo testing. Among the in vitro experimental conditions, the corrosion rate in SBF solution had the least difference from the in vivo implanted specimen.

• Journal of Environmental Science International
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• v.22 no.11
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• pp.1383-1388
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• 2013

The pilot plant experiment was performed to investigate phosphorus and nitrogen removal from domestic wastewater by MLE process combined with aluminum corrosion reactor. When operating 0.5Q and 1Q to internal recycle and sludge recycle in the MLE process, the effluent $COD_{Mn}$ concentration of internal recycle 0.5Q were higher than internal recycle 1Q, the removal efficiency rates of $NH_3$-N in the internal recycle 0.5Q were was higher than internal recycle 1Q. Denitrification rates were about 86.8% in internal recycle and sludge recycle 0.5Q. When operating 0.5Q to internal recycle and sludge recycle in the MLE process, the removal efficiency rates of total nitrogen was the highest. The removal efficiency rates of total phosphorus was about 91.5% in the aluminum corrosion reactor.

• Corrosion Science and Technology
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• v.14 no.1
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• pp.25-32
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• 2015

The alloy content of structural materials of nuclear power plants has been recognized an important factor in predicting flow accelerated corrosion (FAC). In particular, many literature data reported that chromium content is one of the most important alloying element and even a small amount of chromium is effective to suppress FAC. This report reviewed and compared chromium models of Ducreux, Bouchacourt, and Kastner which were used in predicting FAC rates. The plant data indicate that Ducreux model may be conservative for the specimen containing 0.15 wt% chromium. The related articles were reviewed as follows. Combined effects of chromium content, pH, temperature, dissolved oxygen (DO), flow velocity, test time, and kinds of amine on the FAC rate were described. 0.1 wt% chromium in steel did not affect the FAC rate with changes in pH. The FAC rates pronounced with higher flow rate and increased with increasing test duration(600 d) for 0.013 wt% chromium. The FAC rates in mixed amine chemistry were higher than in ammonia chemistry, which may be lessened by the addition of chromium to the steel.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.4
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• pp.437-445
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• 2022

This paper presents an experimental study on the main management factors of the condenser contamination such as fouling and corrosion for the R-134a turbo-chiller to save energy, reduce corrosion rates, and reduce maintenance costs through the application of condenser non-cleaning water treatment chemical. The series of experiment is conducted using combining oxidative microbial sterilizers, non-oxidizing microbial sterilizers, and anti-corrosion agents. The leaving temperature difference and corrosion rates for three different combination of chemicals are collected and analyzed. The experimental results show that the cost reduction (4,066,000 Won/year) of the disinfectant (FT-830) can be achieved by adding the oxidative disinfectant (NaOCl) and the non-oxidizing disinfectant (NX-1116). The LTD value is maintained at 1.9℃, and the corrosion rates of copper and carbon steel specimens are 0.07 mpy and 1.61 mpy, respectively.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.6
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• pp.965-971
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• 2001

To estimate the reliability of 12Cr alloy steel, the material of turbine blade in the steam power plant, Its corrosion susceptibility and fatigue characteristics in NaCl and Na$_2$SO$_4$solution with the difference of concentration and temperature was investigated. The polarization tests recommended in ASTM G5 standard for corrosion susceptibility in the various corrosive solutions was estimated. It showed that the higher temperature, the faster corrosion rates and corrosion rates were the fastest in 3.5 wt.% NaCl and 1M Na$_2$SO$_4$solution. From these results, the degradation conditions were determined in distilled water, 3.5 wt.% NaCl and 1M Na$_2$SO$_4$solution at room temperature, 60$\^{C}$ and 90$\^{C}$ during 3, 6 and 9 months. Its surface had a few pits for long duration. But, it was not susceptible in sulfide and chloride condition of several temperatures. If the degraded 12Cr alloy steel and non-degraded one were compared with fatigue characteristics, Any differences were not found regardless of temperature and degradation period.

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.276-281
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• 2006

Although fireside corrosion of heat transfer surfaces in coal fired steam generators has been a problem to some extent for a number of tears, with the advent of low NOx firing systems these surfaces can be exposed to conditions that will exacerbate wastage rates. Numerous reports of waterwall wastage in coal fired boilers have appeared in the literature. It is believed that wastage results both from gaseous phase attack of metal surfaces and from deposition of ash and unburned fuel. Gaseous phase attack is known to occur in the presence of reducing sulfur species such as $H_2S$ and in the presence of fuel chlorine. The highest wastage rates are thought to be due to deposition of unoxidized material and the presence of fuel chlorine. Localized wall and near wall conditions that may exacerbate wastage include reducing conditions, high temperatures, high heat fluxes, and a high fraction of unoxidized material deposited. So, this study is directed at developing an advanced corrosion model in coal-fired utility boilers.

• Proceedings of the KWS Conference
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• 1997.05a
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• pp.35-38
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• 1997

In order to investigate quantitative behavior of galvanic corrosion in the weld joint between stainless steel and carbon steel, electrochemical polarization experiments are performed for various pH, water temperature with boric acid concentration 4000ppm. The corrosion rate of stainless steel was almost independent of the variation of pH. The significant corrosion rates of carbon steel and the weld joint of carbon-carbon steel were observed at pH 4. The corrosion rates in the weld joint of the carbon-stainless steel were observed depending on the variation of pH level.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.545-548
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• 2006

This study includes the experimental investigation on the fatigue-bond behavior with respect to the various rates of steel corrosion. Major criteria of test variables are the rates of steel corrosion by chloride ion and the ratio of the applied stress to the bond failure stress. According to the test results, the slip versus number of load cycles relation was found to be approximately linear in double logarithmic scale, not only without steel corrosion but also with steel corrosion. This research will be helpful for the realistic durability design and condition assessment of reinforced concrete structures.