• Title, Summary, Keyword: Galvanic corrosion

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An Electrochemical Evaluation on the Corrosion of Weld Zone in Cold Arc Welding of the Cast Iron

  • Moon, Kyung Man;Kim, Jin Gyeong;Lee, Myung Hoon;Kim, Ki Joon
    • Corrosion Science and Technology
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    • v.7 no.2
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    • pp.134-137
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    • 2008
  • Cold arc welding of cast iron has been widely used with repair welding of metal structures. However its welding is often resulted in the galvanic corrosion between weld metal zone and heat affected zone(HAZ) due to increasing of hardness. In this study, corrosion properties such as hardness, corrosion potential, surface microstructures, and variation of corrosion current density of welding zone with parameters of used electrodes for cast iron welding were investigated with an electrochemical evaluation. Hardness of HAZ showed the highest value compared to other welding zone regardless of kinds of used electrodes for cast iron welding. And its corrosion potential was also shifted to more negative direction than other welding zone. In addition, corrosion current density of WM in polarization curves was qualitatively smaller than that of HAZ. Therefore galvanic corrosion may be apparently observed at HAZ. However galvanic corrosion may be somewhat controlled by using an optimum welding electrode.

Influence of Graphite Epoxy Composite Material on the Electrochemical Galvanic Corrosion of Metals (금속재료의 전기화학적 갈바닉 부식에 미치는 GECM의 영향)

  • Yoo, Y.R.;Son, Y.I.;Shim, G.T.;Kwon, Y.H.;Kim, Y.S.
    • Corrosion Science and Technology
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    • v.8 no.1
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    • pp.27-39
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    • 2009
  • Non metallic composite materials, for example, GECM(graphite epoxy composite material) show high specific strength because of low density. These kinds of non metallic composite materials improved the structural effectiveness and operation economics. However, if these materials contacted several metals, corrosion can be arisen since non metallic composite materials have electrical conductivity. This paper dealt with galvanic corrosion between graphite epoxy composite material and several metals. Base on the electrochemical galvanic corrosion test between GECM and metals, corrosion current of carbon steel and aluminium increased with time but corrosion current of stainless steels and titanium decreased and galvanic potential increased. This behavior shows the galvanic corrosion depends upon the presence of passive film. Also, galvanic effect of GECM coupled with ferrous alloys and non-ferrous alloys was lower than that of 100% graphite, which is attributed to lower exposed area of graphite fiber in the GECM than apparent area of the GECM specimen used for the calculation of galvanic current in this work.

The Study on the Galvanic Corrosion of Al-alloy for Heat Exchanger (Al합금 열교환기의 전지작용부식에 관한 연구)

  • LIM, U-Jo;LEE, Eun-Jeong
    • Journal of Fisheries and Marine Sciences Education
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    • v.15 no.1
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    • pp.115-122
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    • 2003
  • Generally, material for radiator of automobile is composed of Al-alloy, but part of radiator material is still composed of Cu. Specially, Al-alloy replaces Cu and Cu-alloy as cooling and heating system material for light weight. Therefore, galvanic electronic cell is formed between Al-alloy and Cu for automobile radiator material, and Al-alloy corrosion is accelerated. So, in this study, galvanic corrosion test of Al-alloy coupling with Cu was carried out in distilled water, tap water, polluted environment and non-freezing solution. And thus corrosion potential and galvanic currrent density of Al-alloy coupling with Cu is investigated.

Influences of Anodizing and Thermal Oxidation on the Galvanic Corrosion between Aluminium and Titanium and GECM (GECM과 Al 및 Ti 간의 갈바닉 부식에 미치는 양극산화 및 열산화의 영향)

  • Kim, Young-Sik;Lim, Hyun-Kwon;Sohn, Young-Il;Yoo, Young-Ran;Chang, Hyun-Young
    • Korean Journal of Metals and Materials
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    • v.48 no.6
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    • pp.514-522
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    • 2010
  • Graphite epoxy composite material (GECM) shows high specific strength and its application in the aerospace industry is gradually increasing. However, its application would induce galvanic corrosion between GECM and metallic materials. This work focused on the effects of anodizing and thermal oxidation on galvanic corrosion in a 3.5% NaCl solution between GECM and aluminium and titanium. In the case of anodized aluminium, galvanic corrosion resistance to the GECM was greatly improved by the anodizing treatment regardless of area ratio. In the case of anodized titanium, the anodizing by a formation voltage of 50V increased corrosion resistance of titanium in galvanic tests. Thermal oxidation of titanium also improved corrosion resistance of Ti to GECM.

Galvanic Sensor System for Detecting the Corrosion Damage of the Steel in Concrete

  • Kim, Jung-Gu;Park, Zin-Taek;Yoo, Ji-Hong;Hwang, Woon-Suk
    • Corrosion Science and Technology
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    • v.3 no.3
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    • pp.118-126
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    • 2004
  • The correlation between sensor output and corrosion rate of reinforcing steel was evaluated by laboratory electrochemical tests in saturated $Ca(OH)_2$ with 3.5 wt.% NaCl and confirmed in concrete environment. In this paper, two types of electrochemical probes were developed: galvanic cells containing of steel/copper and steel/stainless steel couples. Potentiodynamic test, weight loss measurement, monitoring of open-circuit potential, linear polarization resistance (LPR) measurement and electrochemical impedance spectroscopy (EIS) were used to evaluate the corrosion behavior of steel bar embedded in concrete. Also, galvanic current measurements were conducted to obtain the charge of sensor embedded in concrete. In this study, steel/copper and steel/stainless steel sensors showed a good correlation in simulated concrete solution between sensor output and corrosion rate of steel bar. However, there was no linear relationship between steel/stainless steel sensor output and corrosion rate of steel bar in concrete environment due to the low galvanic current output. Thus, steel/copper sensor is a reliable corrosion monitoring sensor system which can detect corrosion rate of reinforcing steel in concrete structures.

EVALUATION OF GALVANIC CORROSION BEHAVIOR OF SA-508 LOW ALLOY STEEL AND TYPE 309L STAINLESS STEEL CLADDING OF REACTOR PRESSURE VESSEL UNDER SIMULATED PRIMARY WATER ENVIRONMENT

  • Kim, Sung-Woo;Kim, Dong-Jin;Kim, Hong-Pyo
    • Nuclear Engineering and Technology
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    • v.44 no.7
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    • pp.773-780
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    • 2012
  • The article presented is concerned with an evaluation of the corrosion behavior of SA-508 low alloy steel (LAS) and Type 309L stainless steel (SS) cladding of a reactor pressure vessel under the simulated primary water chemistry of a pressurized water reactor (PWR). The uniform corrosion and galvanic corrosion rates of SA-508 LAS and Type 309L SS were measured in three different control conditions: power operation, shutdown, and power operation followed by shutdown. In all conditions, the dissimilar metal coupling of SA-508 LAS and Type 309L SS exhibited higher corrosion rates than the SA-508 base metal itself due to severe galvanic corrosion near the cladding interface, while the corrosion of Type 309L in the primary water environment was minimal. The galvanic corrosion rate of the SA-508 LAS and Type 309L SS couple measured under the simulated power operation condition was much lower than that measured in the simulated shutdown condition due to the formation of magnetite on the metal surface in a reducing environment. Based on the experimental results, the corrosion rate of SA-508 LAS clad with Type 309L SS was estimated as a function of operating cycle simulated for a typical PWR.

Galvanic Corrosion of Zn/Steel Couple in Aqueous MgCl2

  • Tada, E.;Katakami, S.;Nishikata, A.
    • Corrosion Science and Technology
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    • v.16 no.4
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    • pp.183-186
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    • 2017
  • Galvanic corrosion tests of Zn/steel couples were conducted in 1 M NaCl and $1M\;MgCl_2$ solutions to investigate the impact of magnesium ion on corrosion behavior of the couples. Two types of Zn/steel couples were used for measurements of open circuit potential (OCP) and galvanic current. From the results of OCP transient of Zn/steel couples, the corrosion potential in $1M\;MgCl_2$ was a more positive value than that in 1 M NaCl during the sacrificial dissolution of Zn. However, earlier increase of OCP of the couples in $1M\;MgCl_2$ solution indicates that the sacrificial dissolution rate of Zn in $1M\;MgCl_2$ was enhanced more than that in 1 M NaCl, agreeing with the results on transients of galvanic current. This result is due to that cathodic reaction on the steel surface of the Zn/steel couple was enhanced in $1M\;MgCl_2$ by the occurrence of hydrogen evolution reaction.

A Galvanic Sensor for Monitoring the External and Internal Corrosion Damage of Buried Pipelines

  • Choi, Yoon-Seok;Kim, Jung-Gu;Hwang, Woon-Suk
    • Corrosion Science and Technology
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    • v.4 no.5
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    • pp.178-190
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    • 2005
  • In order to develop a new corrosion sensor for detecting and monitoring the external and internal corrosion damage of buried pipeline, the electrochemical property of sensors and the correlation of its output to corrosion rate of steel pipe, were evaluated by electrochemical methods in two soils of varying resistivity (5,000 ohm-cm, 10,000 ohm-cm) and synthetic tap water environments. In this paper, two types of galvanic probes were manufactured: copper-pipeline steel (Cu-CS) and stainless steel-pipeline steel (SS-CS). The corrosion behavior in synthetic groundwater and synthetic tap water for the different electrodes was investigated by potentiodynamic test. The comparison of the sensor output and corrosion rates revealed that a linear relationship was found between the probe current and the corrosion rates. In the soil resistivity of $5,000{\Omega}-cm$ and tap water environments, only the Cu-CS probe had a good linear quantitative relationship between the sensor output current and the corrosion rate of pipeline steel. In the case of $10,000{\Omega}-cm$, although the SS-CS probe showed a better linear correlation than that of Cu-CS probe, the Cu-CS probe is more suitable than SS-CS probe due to the high current output.

Corrosion Resistance of Zn and Cu Coated Steel Pipes as a Substitute for Cu Pipe in an Air Conditioner System

  • Shin, Jae-Gyeong;Park, Chan-Jin;Hong, Sung-Kil
    • Corrosion Science and Technology
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    • v.8 no.1
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    • pp.40-43
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    • 2009
  • We investigated the corrosion resistance of Zn and Cu coated steel pipes as a substitute for Cu pipe in an air-conditioner system. In addition, the galvanic corrosion tendency between two dissimilar metal parts was studied. The corrosion resistance of the Cu electroplated steel was similar to that of Cu, while the corrosion rate of the Zn electro- galvanized and the galvalume (Zn-55 % Al) coated steels was much higher and not suitable for Cu substitute in artificial sea water and acidic rain environments. Furthermore, the galvanic difference between Cu electroplated steel and Cu was so small that the Cu coated steel pipe can be used as a substitute for Cu pipe in an air-conditioner system.

Corrosion Behavior Analysis of the Weld Joint between Stainless Steel and Carbon Steel (스테인리스강과 탄소강 용접부의 부식거동 해석)

  • 권재도;이우호;김길수;장순식;진영준
    • Journal of Welding and Joining
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    • v.17 no.3
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    • pp.66-70
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    • 1999
  • In order to investigate the quantitative behavior of galvanic corrosion in weld joints between stainless std이 and carbon steel, electrochemical polarization experiments were performed at pH4, pH7 and pH10 with boric acid concentration 4000ppm, and water temperature were selected as $35^{\circ}$C and $60^{\circ}$C. As the results, the galvanic corrosion phenomena of carbon steel weld material at $60^{\circ}$C was revealed $2{1\over2}$ times higher corrosion rate than that at $35^{\circ}$C condition. The corrosion rate of stainless steel was almost inedependent 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.

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