• Title, Summary, Keyword: Galvanic corrosion

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Galvanic Corrosion between Carbon Steel 1018 and Alloy 600 in Crevice with Boric Acid Solution

  • Kim, Dong Jin;Macdonald, Digby D.;Kim, Hong Pyo;Kim, Joung Soo
    • Corrosion Science and Technology
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    • v.4 no.3
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    • pp.75-80
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    • 2005
  • This work dealt with the evaluation of galvanic corrosion rate in a corrosion cell having annular gap of 0.5 mm between carbon steel 1018 and alloy 600 as a function of temperature and boron concentration. Temperature and boron concentration were ranged from 110 to 300 $^{\circ}C$ and 2000~10000 ppm, respectively. After the operating temperature of the corrosion cell where the electrolyte was injected was attained at setting temperature, galvanic coupling was made and at the same time galvanic current was measured. The galvanic corrosion rate decreased with time, which was described by corrosion product such as protective film as well as boric acid deposit formed on the carbon steel with time. From the galvanic current obtained as a function of temperature and boron concentration, it was found that the galvanic corrosion rate decreased with temperaturewhilethe corrosionrate increasedwith boronconcentration. The experimental resultsobtained from galvanic corrosion measurement were explained by adhesive property of corrosion product such as protective film, boric acid deposit formed on the carbon steel wall and dehydration of boric acid to be slightlysolubleboric acid phase.Moreoverthe galvaniccorrosionrate calculatedusing initialgalvaniccoupling current instead of steady state coupling current was remarked, which could give us relatively closer galvanic corrosion rate to real pressurized water reactor.

Study on Prevention of Galvanic Corrosion between Carbon Steel Rivets and Graphite Used in Aluminum Matrix Automobiles (알루미늄 기지 자동차에 쓰이는 탄소강 리벳과 그라파이트간의 갈바닉 부식 방지 연구)

  • Seo, Dong-Il;Lee, Jae-Bong
    • Corrosion Science and Technology
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    • v.16 no.3
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    • pp.128-140
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    • 2017
  • Aluminum alloy matrix may be used for manufacturing lighter automobiles. However, galvanic corrosion may occur between the rivet joint combining aluminum alloy matrix and a CFRP (carbon fiber reinforced plastic) laminate. The possibility of galvanic corrosion may be investigated by measuring galvanic couple currents. Two types of galvanic current measuring methods were used. One method is to use potentiodynamic polarization curves and the other is the ZRA (zero resistance ammeter) method. For galvanic corrosion experiments graphite, a major component of CFRP, was used with carbon steel (rivets) and 6061 aluminum alloys. Regardless of carbon steel, Ni deposited carbon steel, and 316L stainless steels we also investigated the possibility of reduction in galvanic corrosion. Results revealed that even though Ni deposited carbon steel or 316L stainless rivet may slightly increase galvanic current density between those and Al matrix, substitute rivets for carbon steel may be considerably useful for reducing overall galvanic corrosion.

A Study on the Galvanic corrosion and its Protection on Heat Exchanger Tube Plate (열교환기 관판의 전지작용부식과 방지에 관한 연구)

  • 임우조;홍성희;윤병두
    • Journal of the Korean Society of Marine Engineering
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    • v.25 no.2
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    • pp.344-350
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    • 2001
  • This paper was studied on the characteristics of galvanic corrosion and its protection on heat exchanger tube plate in the sea water. In this paper, behavior of pitting corrosion of Ni-al bronze connected with Ti tube was measured af flow velocity of 0 m/s and 2.4 m/s. To protect galvanic corrosion, the protection characteristics of Ni-Al bronze connected with Ti tube by Zn-base alloys galvanic anode and hexagonal nylon insert was investigated. Main results obtained asre al follows: 1) The galvanic corrosion of Ni-Al bronze connected with Ti-tube is more active than single Ni-al bronze. 2) As the circuit resistance increase under the cathodic protection employing Zn-base alloys galvanic anode, Ni-al bronze connected with Ti tube is cathodically unpolarized. 3) The corrosion of Ni-Al bronze connected with Ti tube by nylon insert controls approximately 73% than not nylon insert.

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Effect of Area Ratio on Galvanic Corrosion Between Metallic Materials and GECM in 3.5% NaCl Solution (3.5% NaCl 수용액 중에서의 금속과 GECM의 갈바닉 부식에 미치는 면적비의 영향)

  • Kim, Y.S.;Lim, H.K.;Sohn, Y.I.;Yoo, Y.R.;Chang, H.Y.
    • Corrosion Science and Technology
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    • v.9 no.1
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    • pp.39-47
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    • 2010
  • Galvanic coupling between GECM(graphite epoxy composite material) and metallic materials can facilitate corrosion of metals and alloys because GECM is noble and electrically conductive. Galvanic corrosion is affected by many factors including metallic materials, area ratio, surface condition, and corrosivity. This work aims to evaluate the effect of area ratio on galvanic corrosion between GECM and several metals. In the case of glavanic coupling of carbon steel and Al to GECM, corrosion rate increased with increasing area ratio. Corrosion rate of sensitized STS 316S stainless steel decreased a little at an area ratio 1:1 but increased at an area ratio 30:1. It is considered to be due to that area ratio affects galvanic corrosion more in less corrosion resistant alloys. However, in case of STS 316 and Ti, galvanic coupling reduces corrosion rate by the formation of passive film.

Galvanic Corrosion Behavior between Carbon Steel Bolted GECM(Graphite Epoxy Composite Material)/Al plates (탄소강 볼트 체결된 GECM(Graphite Epoxy Composite Material)/Al 판재 간의 갈바닉 부식 거동)

  • Kim, Youngsik;Park, Sujin;Yoo, Youngran
    • Corrosion Science and Technology
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    • v.12 no.1
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    • pp.12-26
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    • 2013
  • This work focused on galvanic corrosion of carbon steel bolted GECM/Al plates by long-term test in tap water and NaCl solutions. Test product was carbon steel bolted between cross packed GECM and painted aluminium. Tests for the product and coupled parts determined corrosion rate in tap water and NaCl solutions. Also, using a potentiostat and salt water sprayer, galvanic test was done. In galvanic test on carbon steel bolted GECM/Al plates, corrosion of carbon steel bolt was faster in series of tap water>1% NaCl solution>3.5% NaCl solution. In galvanic couple between aluminium and carbon steel bolt, their corrosion rates were higher than those of single specimen. In galvanic couple between GECM, aluminium, and carbon steel bolt, corrosion behaviors of carbon steel bolt and aluminium were changed due to different corrosion mechanism in tap water and chloride solution.

An Electrochemical Study on the Corrosion Property of Materials for Sea Water Heat Exchange System (해수 열교환기용 재료의 부식특성에 관한 전기 화학적 연구)

  • 김진경;김강희;김성종;박근현;문경만
    • Journal of the Korean Society of Marine Engineering
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    • v.26 no.1
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    • pp.99-107
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    • 2002
  • Recently all kinds of structural materials are subjected to the severe corrosive environment. Especially corrosion problems of heat exchanger such as galvanic corrosion, erosion and cavitation raised by both contaminated solution and high velocity of fluid to increase cooling effect of heat exchanger have been frequently reported in these days. In this study two kinds of sheet materials and five kinds of tube materials are used for galvanic corrosion characteristics and their corrosion current density calculation. The tube materials having the most galvanic corrosion resistance between tube and sheet of heat exchanger were Al Brass(68700) and Al Brass(C6872TS) and although Ti tube predominantly indicated the highest individual corrosion resistance among those five tube materials. it appeared that Ti tube can be allowed as sheet materials to get galvanic corrosion easily. However it is considered that Cu-Ni tube materials is not only easy to produce galvanic corrosion significantly between tube and sheet regardless of kinds of sheet materials but also is appeared considerably its own high corrosion current density

Prevention of Crevice Corrosion of STS 304 Stainless Steel by a Mg-alloy Galvanic Anode

  • Lim, U.J.;Yun, B.D.;Kim, J.J.
    • Corrosion Science and Technology
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    • v.5 no.3
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    • pp.90-93
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    • 2006
  • Prevention of crevice corrosion was studied for STS 304 stainless steel using a Mg-alloy galvanic anode in solutions with various specific resistivity. The crevice corrosion and corrosion protection characteristics of the steel was investigated by the electrochemical polarization and galvanic corrosion tests. Experimental results show that the crevice corrosion of STS 304 stainless steel does not occur in solutions of high specific resistivity, but it occurs in solutions of low specific resistivity like in solutions with resistivities of 30, 60 and $115{\Omega}{\cdot}m$. With decreasing specific resistivity of the solution, the electrode potential of STS 304 stainless steel in the crevice is lowered. The potential of STS 304 stainless steel in the crevice after coupling is cathodically polarized more by decreasing specific resistivity indicating that the crevice corrosion of STS 304 stainless steel is prevented by the Mg-alloy galvanic anode.

Galvanic Corrosion of AZ31 Mg Alloy Contacting with Copper

  • Phuong, Nguyen Van;Moon, Sungmo
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • pp.151.1-151.1
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    • 2017
  • This work studied the corrosion behavior of AZ31 Mg alloy galvanically coupled with Cu during immersion in 0.1 and 0.5 M NaCl solutions by in-situ observation and galvanic corrosion current measurement using a zero resistance ammeter. The corrosion behavior of AZ31 Mg alloy was also studied by salt spray test. The average galvanic corrosion density during 2 h immersion in 0.1 NaCl solution was found to decrease as an exponential function with increasing the surface area ratios between AZ31:Cu or with increasing the distance between AZ31 and Cu. The corrosion of electrodeposited Cu on AZ31 Mg alloy was concentrated at the area next to Cu (about 5 mm for immersion test and 2 mm for salt spray test) and pitting corrosion was accelerated at the area beyond the severely corroded area by the galvanic coupling effect.

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Area Effect on Galvanic Corrosion of Condenser Materials with Titanium Tubes in Nuclear Power Plants (Titanium 전열관을 사용하는 원전 복수기 재료의 Galvanic Corrosion에 미치는 면적의 영향)

  • Hwang, Seong-Sik;Kim, Joung-Soo;Kim, Uh-Chul
    • Nuclear Engineering and Technology
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    • v.25 no.4
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    • pp.507-514
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    • 1993
  • Titanium tubes have recently been used in condensers of nuclear power plants since titanium has very good corrosion resistance to seawater. However, when it is connected to Cu alloys as tube sheet materials and these Cu alloys are connected to carbon steels as water box materials, it makes significant galvanic corrosion on connected materials. It is expected from electrochemical tests that the corrosion rate of carbon steel will increase when it is galvanically coupled with Ti or Cu in sea water and the corrosion rate of Cu will increase when it is coupled with Ti, if this couple is exposed to sea water for a long time. It is also expected that the surface area ratios, R$_1$(surface area of carbon steel/surface area of Ti) and R$_2$(surface area of carbon steel/surface area of Cu) are very important for the galvanic corrosion of carbon steel and that these should not be kept to low values in order to minimize the galvanic corrosion on the carbon steel of the water box. Immersed galvanic corrosion tests show that the corrosion rate of carbon steel is 4.4 mpy when the ratio of surface area of Fe/ surface area of Al Brass is 1 while it is 570 mpy when this ratio is 10$^{-2}$ . The galvanic corrosion rate of this carbon steel is increased from 4.4 mpy to 13 mpy at this area ratio, 1, when this connected galvanic specimen is galvanically coupled with a Ti tube. This can be rationalized by the combined effects of R$_1$ and R$_2$ on the polarization curve.

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Effects of NaCl Concentration and Solution Temperature on the Galvanic Corrosion between CFRP and AA7075T6

  • Hur, S.Y.;Kim, K.T.;Yoo, Y.R.;Kim, Y.S.
    • Corrosion Science and Technology
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    • v.19 no.2
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    • pp.75-81
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    • 2020
  • To reduce structural weight, light metals, including aluminum and magnesium alloys, have been widely used in various industries such as aircraft, transportation and automobiles. Recently, composite materials such as Carbon Fiber Reinforced Plastics (CFRP) and Graphite Epoxy Composite Material (GECM) have also been applied. However, aluminum and its alloys suffer corrosion from various factors, which include aggressive ions, pH, solution temperature and galvanic contact by potential difference. Moreover, carbon fiber in CFRP and GECM is a very efficient cathode, and very noble in the galvanic series. Galvanic contact between carbon fiber composites and metals in electrolytes such as rain or seawater, is highly undesirable. Notwithstanding the potentially dangerous effects of chloride and temperature, there is little research on galvanic corrosion according to chloride concentration and temperature. This work focused on the effects of chloride concentration and solution temperature on AA7075T6. The increased galvanic corrosion between CRFP and AA7075T6 was evaluated by electrochemical experiments, and these effects were elucidated.