• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.2
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• pp.1-8
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• 2022

The corrosion of reinforcement is the main reason for the performance degradation of concrete structures. The pre-rusted parts of rebar in concrete structures are vulnerable to the corrosion, especially if the structure is exposed to wet or chlorinated environments. In this study, effects of different curing solution on corrosion behavior of the pre-rusted rebars in the cement composites were investigated. HCl(3%) and CaCl₂(10%) solution were utilized to accelerate the pre-rust of the rebar, and each pre-rust condition rebar including reference (RE) were placed in mortar cylinder. Three kinds of samples then were cured in CaCl₂ (3%) solution and tap water respectively for 120 days. Electrochemical polarization and half-cell potential measurement were used to monitor the influence of curing water on the corrosion behavior of pre-rusted steel bar in cement composite. The surface morphology and composition of corroded steel bar were analyzed by scanning electron microscope and energy dispersive X-ray diffraction. The results show that the corrosion rates of pre-rusted samples in both curing water are higher than that of non-pre-rusted samples. The corrosion rates of RE, CaCl₂ and HCl pre-rusted samples in salt water were 8.14, 4.48, 13.81 times higher than those in tap water respectively, on the 120th day.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.190-191
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• 2014

마그네슘 합금을 생체재료로 사용되는데 두가지 중요한 문제점을 가지고 있다. 매우 빠른 부식을 가지고 있으며, 초기 빠른 부식으로 수소기체를 발생하여 인체 내 피부나 골조직의 괴사를 동반한다. 이러한 문제점을 해결하기 위해 생체적합성이 뛰어난 아노다이징 방법을 개발 하였으며, 새롭게 개선된 방법의 특징을 비교하기 위해 이번 실험에서는 불화물이 포함된 전해액으로 아노다이징 처리한 샘플을 제조하여 형태학 분석을 진행 하였고, Hank's solution(생체모사용액)을 사용하여 부식 특성을 분석하였다. 또한 L929 세포를 이용하여 세포독성 평가를 진행하였다. 새롭게 제조한 방법은 기존의 방법과 비교하였을 때, 부식 성능은 비슷하고 생체적합성이 높아 생분해성 금속의 표면처리에 적합하다고 판단된다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2016.07a
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• pp.259-260
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• 2016

본 논문에서는 전력선의 부식에 따른 물성 변화에 대한 확인 및 검증을 위한 연구를 수행하였다. 산업단지 및 염해지역에 설치되어진 송전선로에 사용되고 있는 강심알루미늄연선(Aluminum Conductors Steel Reinforced, ACSR)은 타 지역에 비하여 스페이서, 슬리브 등의 접속부에서의 부식 정도가 상당히 빠르게 진행된다. 따라서 현재와 같은 내용연한을 획일적으로 적용할 수 없으므로 설치된 선로의 주위 환경 및 사용되는 부하의 조건 등이 반영된 합리적인 송전선로 운용이 필요하다.

• 월간 기계설비
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• s.43
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• pp.70-75
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• 1994

한국건설방식연구소(소장 이의호)가 지난해 12월5일 건설회관에서 제1회 국제방식기술세미나를 개최, 건설업계의 관심을 모았다. 이 세미나에서 $\ulcorner$아파트 물탱크 및 수도배관의 부식과 방식$\lrcorner$에 관한 주제발표를 한 이의호 소장은 국내 아파트의 급수관이 대부분 탄소강재나 철근 콘크리트재로 만들어져 부식이 급속히 진행되고 있으므로 이러한 부식현상을 예방하고 맑은 물을 마시기 위해서는 내식성이 우수한 스테인레스강이나 고분자 강력 합성수지로 교체해야 한다고 주장했다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2011.05a
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• pp.116-116
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• 2011

AZ31과 AZ80의 마그네슘합금 소재를 이용하여 분극곡선과 전기화학적 임피던스를 측정하였고, 다른 금속과 접촉하여 대기환경에 노출시킨 부식시험을 하였다. 그 결과 AZ31보다는 AZ80의 부식저항이 더 큰 것을 확인할 수 있었고, 마그네슘 모재가 이종금속과 접촉된 상황에서 Cu>Fe>Al의 접촉재 순으로 부식이 진행되었다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.2
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• pp.191-195
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• 2020

In this work, tensile tests, one of the most common test method to assess the condition of a corroded pipe, were conducted. According to ASTM E8 method, the use of flat or curved uni-axial tension test is allowed under the recommendation with the usage of grips corresponding to a curvature of the pipe. However, this method is not for corroded specimen. Furthermore, in the case of performing the multiple tensile tests with various curvatures, it is desirable not to produce zigs that fit each curvatures, if merely processing the specimen grip with curvature into the flat grip can show almost identical tensile behavior. Therefore, various tension simulations were conducted first to check if there exist any differences. Also, experiments on corroded tensile specimen were conducted and compared with the FEM simulation that reflects the actual geometry acquired from the 3D scanner.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.2A
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• pp.293-300
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• 2006

There is a high degree of uncertainty in measurements of the thickness or the loss of thickness of corroded elements. Generally the thickness of corroded elements varies from one location of the element to another depending on the degree of corrosion, which makes the safety assessment difficult. Therefore, a procedure for safety assessment of corrosion- damaged steel structures using an imprecise reliability is proposed in this paper. The proposed safety assessment procedure using the imprecise reliability was also applied to a cable-stayed bridge in Korea to demonstrate its effectiveness and applicability. Since there is a large variation in measurements of the thickness of corroded elements, the thickness of corroded elements was considered as the imprecise element. This variation was found to be directly related to the degree of corrosion. Therefore, the variation increases as the degree of corrosion increases. Based on the comparative observations between the conventional reliability and the imprecise reliability, it is suggested that the imprecise reliability analysis derived based on the subjective or statistical judgment of conditional independence could be successfully utilized for the risk or safety assessment of corrosion-damaged structures.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2013.05a
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• pp.116-116
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• 2013

(Ni-22Cr-10Al-1Y)와 ($ZrO_2-25CeO_2-2.5Y_2O_3$)로 구성되는 금속/세라믹 복합코팅을 대기용사(ASP; air plasma spay)으로 철 기판위에 1:3, 2:2, 3:1의 무게비로 혼합하여 제조하였다. 용사된 코팅은 금속이영지역과 세라믹잉여지역으로 구별되고, 용사중에 NiCrAlY중의 Al이 선택적으로 산화되어 Al2O3가 계면에 존재하였다. 복합코팅은 $NaCl-Na_2SO_4$ 용융염에서 $800{\sim}900^{\circ}C$, 50시간 동안 부식실험을 실시하였다. 부식생성물은 NiO, $Cr_2O_3$, ${\alpha}-Al_2O_3$가 생성되는데, 부식이 진행되면서 용해되었다. 용융염 부식이 진행되는 동안에 Cr, Al이 외방확산하였고, Na, Cl, S는 내부로 확산되었다. 시간 및 온도뿐만 아니라 금속의 양이 증가할수록 코팅의 내식성은 저하되었다.

• Journal of Conservation Science
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• v.26 no.4
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• pp.437-443
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• 2010

The influence of noxious corrosive gas, which is the product of fossil fuel, and the acidic descent material, which becomes the reason for such reaction, on wax which protects the cultural assets, and the habitat factor were researched. It could be viewed that corrosion occurred rapidly due to the acidic descent material, which have the long staying on the material, rather than harmful corrosive gas. Also, it could be figured out that such corrosion began from whitening phenomenon of coated wax. As the acidity increased, more whitening phenomenon occurred, and eventually, it could be found out that whitening effect began due to the acidic descent material, corrosive gas and various 0.1 M acid solution, which lead to the exposure of internal metal, and corrosion occurred. The wax with the greatest resistance to the acidity due to its least changing aspect seemed to be Renaissance wax, except sulfuric acid.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.4
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• pp.421-428
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• 2012

In this study, the effects of surface oxide film formation on the fatigue behavior of 7075-T6 aluminum alloy were analyzed in terms of the corrosion time of the alloy. The aluminum material used is known to have high corrosion resistance due to the passivation phenomenon that prevents corrosion. Aluminum alloys have been widely used in various industrial applications such as aircraft component manufacturing because of their lighter weight and higher strength than other materials. Therefore, studies on the fatigue behavior of materials and passivation properties that prevent corrosion are required. The fatigue behavior in terms of the corrosion time was analyzed by using a four-pointing bending machine, and the surface corrosion level of the aluminum material in terms of the corrosion time was estimated by measuring the surface roughness. In addition, fractographic analysis was performed and the oxide films formed on the material surface were studied by scanning electron microscopy (SEM). The results indicated that corrosion actively progressed for four weeks during the initial corrosion phase, the fatigue life significantly decreased, and the surface roughness increased. However, after four weeks, the corrosion reaction tended to slow down due to the passivation phenomenon of the material. Therefore, on the basis of SEM analysis results, it was concluded that the growth of the surface oxide film was reduced after four weeks and then the oxide film on the material surface served as a protection layer and prevented further corrosion.