• Corrosion Science and Technology
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• v.4 no.2
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• pp.56-59
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• 2005

In rebar concrete structure, the corrosion of rebar can arise the deterioration of concrete structure and may affect the safety of the whole system. Recently, several methods for corrosion protection have been used and are more important for concrete structure using the sand including chloride ion. Among several protections, electrical cathodic protection has been expected to be one of the most useful methods in corrosion protection for reinforcement of concrete structures. The anode for cathodic protection needs high current density, high corrosion resistance and low overvoltage. To fill up the special qualities, the insoluble anodes were developed and these anodes were coated with metal oxide of $TiO_2$, $ZrO_2$, $RuO_2$, and $IrO_2$. Lifetime of these anodes can be one of the important factors affecting the lifetime of concrete structure in cathodic protection. In this work, several anodes were made by sol-gel method and thermal decomposition method and the lifetime of these anodes was evaluated by NACE international standard test method, TM 0294-94. Also, we did analyze the properties of coated metal oxides.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.2
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• pp.213-220
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• 1999

The purpose of this study is to apply cathodic protection to reinforced concrete structure and provide fundamental data to prevent the corrosion. The theory of cathodic protection of steel in concrete is to apply sufficient direct current so that corroding anodes on the steel are prevented from discharging ions. Two methods are used to supply the external current. In one, the protected metal is the cathode by connecting it to a more active metal. In the second, an external direct current power source supplies the current. The first is the sacrificial-anode system and the second the impressed-current system. The study results showed that the corrosion of the reinforcing steel in concrete could be enormously decreased by using protective current. The sacrificial anode and concrete nave to be adhered closely each in order to prevent the corrosion of reinforcing steel.

• Journal of Navigation and Port Research
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• v.30 no.4
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• pp.291-294
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• 2006

Corrosion is never avoided in the use rf materials with various environments. The underwater hull is normally protected against rusting by several coatings of anti-corrosive paint. The purpose of ICCP(Impressed Current Cathodic Protection) system is to eliminate the rusting or corrosion, which occurs on metal immersed in seawater. This thesis is about the ICCP control and monitoring system, which brings protection against the corrosion of the ship's hull in the sea environments. The test system for ICCP is composed of a power supply, anode, reference electrode and controller. The test system is composed power supply, anode, ref electrode, shunt and etc. The protection current is sent to the protection area though anode. Reference electrode senses whether or not the detected potential is within a range of protection of test equipment and then it is automatically controlled to increase or decrease the amount of protective current to be sent to the anode by controller. The monitoring system with LabView is also detected in order to check the normal state of the system at operation period, because an operator does not always watch over this system and thus the system cannot operate well because rf his or her negligent management. This paper was studied the variation of potential and current density with environment factors, velocity and time, and the experimental results will be explained Also, It is suggested that this system can accommodate a ship's automation for SCMS(Ship Control and Management System) and will be very useful.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.104-106
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• 2004

There are many under grounds facilities like oil pipes, gas pipes, water pipes, oil tanks, etc. and severe corrosion of these facilities made big problems. Fire, wide area water and soil pollution, massive and hazardous explosion, etc. can make big problems and cause big economical loss. So, various technologies were developed to keep these undergrouns facilities safely, and cathodic protection is one of it. For cathodic protection, one must detect potential of pipes, and there are so many test box to check pipes potentials. In this thesis, we describe on the development of small size corrosion monitoring system that measure pipes potentials easily and economically.

• Tribology and Lubricants
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• v.11 no.1
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• pp.58-65
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• 1995

When marine lubricating oil began to be emulsified and oxidized through ingressive water that have leaked from cooling pump seal systems, cooler, purifier system and piping system, the cavitation erosion-corrosion in alloy metals of bearings remains to the various troublesome problem at effective engine performance. Therefore, applied the cathodic protection to the control test of cavitation erosion-corrosion, and appointed the marine system oil containing 3% sea water as test environments, with different conductibility. Also, used the piezoelectric vibrator with 20 KHz, 24 $\mu$m as the cavity generation apparatus, and examined the weight loss, potential value, current density etc. in specimens with those condition. According to this testing data, investigated influence of cathodic protection on the control characteristics of cavitation erosion-corrosion, and will serve those as an elementary design data of marine bearing.

• Corrosion Science and Technology
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• v.10 no.3
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• pp.101-107
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• 2011

Marine ships have played an important role as a carrier, transporting much more than 80% of all international trading, and marine transportation is an internationally competitive, strategic, and great national important industry. However, those marine ships have the characteristics such as voyage of long distance, large-volume and lower speed than the other carry system. Therefore, it is important to manufacture a larger and faster ship, however, the steel plates which are consisted with most of those ships has brought about many corrosion problems in sea water such as general corrosion, localized corrosion, cavitation and erosion corrosion etc.. Most hulls of the ships have been protected with paintings, sacrificial anode, marine growth prevention system, and impressed current cathodic protection methods against numerious corrosion problems mentioned above. However, these conventional methods are not very effective because the rudder of ships stern are exposed to very severe corrosive environment such as tides, speeds of ships, cavitations and erosion corrosion, etc.. In this study, electrochemical and cavitation characteristics was investigated for the rudder material of ship which is exposed to serious corrosive environment. As a result, it is considered that the optimum cathodic protection potentials of rudder material is the range of -0.6 V ~ -0.8 V(Ag/AgCl) in static seawater.

• Corrosion Science and Technology
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• v.4 no.4
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• pp.140-146
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• 2005

Fossil fired power plant produces the electric energy by using a thermal energy by the combustion of fossil fuels as like oil, gas and coal. The exhausted flue gas by the combustion of oil etc. contains usually many contaminated species, and especially sulfur-content has been controlled strictly and then FGD (Flue Gas Desulfurization) facility should be installed in every fossil fired power plant. To minimize the content of contaminations in final exhaust gas, high corrosive environment including sulfuric acid (it was formed during the process which $SO_2$ gas combined with $Mg(OH)_2$ solution) can be formed in cooling zone of FGD facility and severe corrosion damage is reported in this zone. These conditions are formed when duct materials are immersed in fluid that flows on the duct floors or when exhausted gas is condensed into thin layered medium and contacts with materials of the duct walls and roofs. These environments make troublesome corrosion and air pollution problems that are occurred from the leakage of those ducts. The frequent shut down and repairing works of the FGD systems also demand costs and low efficiencies of those facilities. In general, high corrosion resistant materials have been used to solve this problem. However, corrosion problems have severely occurred in a cooling zone even though high corrosion resistant materials were used. In this work, a new technology has been proposed to solve the corrosion problem in the cooling zone of FGD facility. This electrochemical protection system contains cathodic protection method and protection by coating film, and remote monitoring-control system.

• Corrosion Science and Technology
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• v.6 no.5
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• pp.239-244
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• 2007

Corrosion protection of automotive steels has traditionally been assured by using a zinc phosphate metal pretreatment followed by the deposition of a cathodic electrocoat system. This system has been developed and optimized over the years into a highly robust and dependable system with a high performance. However, in terms of efficiency and use of resources and energy, the need is now felt to develop a simpler system with fewer steps, shorter lines, less energy requirements (curing and e-coat deposition) and less stringent waste disposal requirement (phosphate sludge). We report here on the development of a one-step system that can possibly replace both the zinc phosphate and the e-coating processes. Such a system is based on the so-called superprimer concept that we have recently developed for the replacement of chromate pretreatment and chromate-containing primers in the aerospace industry. With some modifications, such systems can also be adapted for use in the automotive industry.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.1207-1212
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• 2001

Reinforced concrete has defects in durability due to carbonation, freezing and thawing, and penetration of chloride ions with elapse of time in spite of super structure. Especially steel corrosion in concrete due to penetration of chloride ions has result in a severe decline in service life. The principal purpose of this study is to estimate effects of sacrificial anode cathodic system, one of the electrochemical methods in order to control of steel corrosion in concrete. There are chloride content in concrete in cracked and non cracked specimen with cathodic protection. To investigate the effect of sacrificial anode cathodic protection, potential-decay with current density, corrosion ratio, etc. are measured. We have the excellent effect for control steel corrosion adaption sacrificial anode cathodic system.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.281-284
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• 1999

Bridge structure is known as one of important infrafacilities for comfortable human life. Recent long-span bridges, such as Kwang-Ahn Grand bridge, S대-Hae Grand Bridge, Young-Jong Grand Bridge, etc, have been designed and constructed near the seaside without in-depth consideration of concrete durability problems, It is in particular noted that corrosion of reinforcement steel in concrete is very important for the durability enhancement of concrete structures. The objective of this experimental study is to investigate the corrosion degree of reinforcing steels in concrete specimens which are exposed to cyclic wet and dry saltwaters, and then to develop pertinent corrosion protection system such as rational cover depth, corrosion inhibitors, cathodic system for reinforced concrete bridges exposed to marine environment.