• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.226-226
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• 2009

일반적으로 알루미늄이나 아연 등과 같은 이온화 경향이 큰 금속들은 그 자체의 활성적인 특성으로 인해 강재와 같은 이온화 경향이 낮은 금속재의 표면에 도금 또는 코팅함으로서 사용 환경 중 자체 내식성 보유와 더불어 손상 결함시 희생양극적인 역할 등의 잇점으로 많이 사용되고 있다. 본 연구에서는 DC 스퍼터링법에 의해 표면조직이 치밀한 여러 가지의 Zn-Mg 합금박막을 제작하였다. 이들 박막은 종래의 Zn도금에 비해 부식환경 중 장기간 갈바닉쌍을 형성하여 모재 금속에 대한 보호막 기능을 우수하게 하는 것으로 나타났다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.05a
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• pp.164-165
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• 2015

보일러 및 압력 용기용 강판으로 사용되는 SB410은 고 항복 강도 및 좋은 용접성의 특성을 가진 재질로서 주로 고압력, 내열성 및 내식성이 필요한 석유플랜트, 액화물 저장 탱크, 화력 발전 보일러 등의 제조에 주로 사용되어지는 탄소 강재이다. 그러나, 최근에는 조선소, 해양 플랜트, 석유화학 플랜트 등 사용환경에 따른 관련 분야에서의 내식성 요구치가 높아지고 있다. 이와 관련하여 현재 보편적으로 사용되어지는 Marin paint coating을 적용한 SB410 강재의 경우에도 사용환경의 가혹화가 증가됨에 따라 요구되는 내식성에 비하여 불량 현상이 증가하는 추세이며 해당 분야에서 본 재질의 표면처리 개선에 대한 연구 개발이 진행되고 있다. 본 연구에서는 Teflon(PTFE) synthetic coating solution을 이용한 SB410 소재 상의 표면처리 공정 최적화를 수행하였으며, 상기 표면처리에 대한 내식성을 검토하기 위하여 Marin paint coating sample, Teflon(PTFE) synthetic coating sample들에 대한 갈바닉 부식 분석 비교를 통하여 내식성에 대한 비교 검증을 수행하였다.

• Journal of the Korea Concrete Institute
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• v.21 no.5
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• pp.565-572
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• 2009

In this study, corrosion resistance of palm oil fuel ash (POFA) concrete as a blended concrete is evaluated by using electrochemical technique. The POFA is an industrial byproduct obtained from fuel ash after extracting palm oil from palm-tree. In order to obtain basic material characteristics of the POFA concrete, tests on compressive strength, slump, weight loss, bleeding and expansion ratio were carried out the early-aged POFA concrete. On the other hand, durability characteristics, both chloride penetration and carbonation depth test, were also conducted. Finally, corrosion resistance were evaluated by applying electro-chemical artificial crack healing technique, and the tests on the impressed voltage characteristic, galvanic current and linear polarization resistance. From the experimental results, it was found that long-term strength, bleeding, lower slump ratio, expansion ratio, chloride penetration, carbonation and corrosion resistance were improved by using the POFA due to activated pozzolanic reaction. It can be also mentioned that POFA concrete has a potential to be used as a cementitious binder for green-recycling resources.

• Journal of the Korea Concrete Institute
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• v.21 no.4
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• pp.409-417
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• 2009

In this study, autogenous crack healing and artificial crack healing using electrochemical electro deposition method were conducted to compare in the aspects of corrosion monitoring. Furthermore, the analysis of impressed voltage characteristics, galvanic current and linear polarization resistance comparison, and photo image processing technique were performed for quantitative comparisons of healing ratio. As a result, it was found that, in view of impressed voltage of artificial crack healing, the measured voltage was increased as time goes by. From the galvanic test results of artificial crack healing, the current vs. potential distribution value were formed widely in comparison with autogenous crack healing. In this point, it was shown that artificial crack healing has more eleatic resistance capacity than autogenous crack healing technique. Finally, it was found that artificial crack healing was 1.63 times higher than autogenous healing in view of crack healing ratio.

• Journal of Ocean Engineering and Technology
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• v.21 no.5
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• pp.39-46
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• 2007

The sea water pipe of a ship's engine room is a severely corrosive environment caused by fast flawing sea water containing chloride ions and high conductivity. Therefore, leaking of sea water may occur as a result of local corrosion of the welded zone. Leaking is usually controlled by various welding methods. In this study, when the sea water pipe is welded with certain welding methods and welding electrodes, the corrosion resistance of WM (Welding metal) and HAZ (Heat affected zone) was investigated using electrochemical methods. Although the corrosion potential of the HAZ is higher than that of WM, the corrosion resistance of WM is superior to HAZ. However, when WM and HAZ are both opened to the sea water, the WM part with the anode was more seriously corroded than was the HAZ of the cathode by performance of a galvanic cell due to difference of the corrosion potential between HAZ and WM. In particular TIG welding showed relatively good results in corrosion resistance of both HAZ and WM compared to other welding methods.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.2
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• pp.160-166
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• 2015

On board hydrogen generation from the hydrolysis of an active metal is very attractive due to its economical, convenient, and safe reasons. A Mg-graphite pellet has been designed as a hydrogen source for portable fuel cell. Mg (1 g) + 0.10 g graphite pellet showed an excellent hydrogen generation rate that is equivalent to 15.8 ml/g.min from its hydrolysis. The hydrogen generation rate of the pellet is significantly increased due to the galvanic corrosion by galvanic cells between Mg anode and graphite cathode in a 10.wt. % NaCl solution at a room temperature.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.6
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• pp.78-88
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• 2000

The effect of post-weld heat treatment(PWHT) of SCM440 steel was investigated with parameters such as micro-Vickers hardness, corrosion potential, polarization behaviors, galvanic current, Al anode generating current and Al anode weight loss, etc. Each hardness of three parts(HAZ, BM, WM) by PWHT is lower than each of as-welded parts. However, hardness of WM area was the highest among those three parts in case of both PWHT and as-welded. Corrosion potential of WM part was the highest among those three parts and WM area was also acted as cathode without regard to PWHT. The magnitude of corrosion potential difference among three parts by PWHT was larger than that of three parts of as-welded, and corrosion current by galvanic cell of these three parts by PWHT was also larger compared to as-welded. Therefore, it is suggested that corrosion resistance property of SCM440 steel is decreased by PWHT than as-welded. However, both Al anode generating current and anode weight loss were also increased by PWHT compared to as-welded when SCM400 steel is cathodically protected by Al anode.

• 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.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.8
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• pp.877-885
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• 2013

A seawater pipe of the engine room in the ships is being surrounded with severely corrosive environments caused by fast flowing of the seawater, containing aggressive chloride ion and high conductivity etc.. Therefore, the leakage of the seawater from its pipe have been often occurred due to its local corrosion by aggressive chloride ions. Subsequently, its leakage area is usually welded by AC shielded metal arc welding with various electrodes. In this study, when the sea water pipe is welded with several types of electrodes such as E4301, E4311, E4313 and E4316, a difference of the corrosion resistance on the welding metal zones was investigated using an electrochemical method, observing microstructure, measuring polarization behaviors and hardness. The weld metal zone welded with E4313 electrode exhibited the lowest value of hardness compared to other weld metal zones. In addition, its zone indicated also the best corrosion resistance than those of other weld metal zones. Furthermore, all of the weld metal zones revealed a relatively better corrosion resistance than those of the base metal zones. and also showed higher hardness than the base metal zones.

• Journal of the Korea Institute of Building Construction
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• v.14 no.6
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• pp.505-513
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• 2014

The purpose of this study is to evaluate the corrosion protective properties of a Zn-Sn metal spray method according to the contents of Zn and Sn by a CASS test and the electrochemical theory. In the experiment, the CASS test and the electrochemical test were conducted to investigate the corrosion protective property of the Zn-Sn Metal Spray system, the Zinc galvanizing system, and the heavy duty coating system. As a result, it was confirmed that the Zn-Sn (65:35) Metal Spray system had very high corrosion protective property through the electrochemical characteristic as comparison with the other anti-corrosion systems and was very effective to prevent steel products from corrosion.