• Corrosion Science and Technology
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• 제21권5호
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• pp.381-389
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• 2022

Cyclic Voltammetry and weight loss measurements were used to investigate corrosion prevention of tin in a 0.5M citric acid solution containing Anthocyanins extracted from grapes at various concentrations and temperatures. Results showed that the investigated chemicals, Anthocyanins extracted from grapes, performed well as tin corrosion inhibitors in 0.5M citric acid. Increasing the concentration of Anthocyanins increased their corrosion inhibition efficiencies. When the temperature dropped, their inhibition efficiencies, increased indicating that higher temperature tin dissolution predominated the adsorption of Anthocyanins at the surface of tin metal. When inhibitor concentrations were increased, their inhibition efficiencies were also increased. These results revealed that corrosion of tin metal was inhibited by a mixed type of adsorption on the metal surface. The adsorption isotherm of Langmuir governed the adsorption of Anthocyanins. Thermodynamic parameters such as the enthalpy of adsorption, the entropy of adsorption, and Gibbs free energy and kinetic parameters such as activation energy, enthalpy of activation, and entropy of activation were computed and discussed in this study.

• 신재생에너지
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• 제3권1호
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• pp.75-82
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• 2007

Aluminum was used as metallic bipolar plate material to reduce a stack weight. The functional materials such as conductive material, Au and nonconductive material, PTFE [polytetrafluoroethylene] were coated on the bipolar plate to enhance electrical contact and corrosion prevention in PEMFC. The active area of bipolar plate is divided into the top layer part that electric current mainly passes, and the bottom layer part that gas and water pass. The bottom layer part in the flow channel needs not to have electrical conductivity because it doesn't pass electric current directly. In this reason, Au on the top layer and PTFE on the bottom layer were coated to apply high electrical conductivity and/or good corrosion resistance. Although the single cell performance using Au-PTFE/Al bipolar plate was shown 78% in comparison with that of graphite, specific power of Au-PTFE/Al bipolar plate(0.4 W/g) was twice as much as graphite bipolar plate.

• 산업기술연구
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• 제18권
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• pp.453-460
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• 1998

The purpose of this study was to analyze their status of underground storage tank(UST) facilities and level of soil contamination, and to establish its management criteria. DB program was developed to analyze the correlation between specific characteristic of UST and level of soil contamination. For a suitable management of UST, leakage monitoring and inspection method of UST was investigated. Inspection period was established based on the leakage rate. The most dominant factor for leakage seemed to be caused by the corrosion. Therefore, main factor, construction method and installation year of UST, and corrosion protection system were suggested for optimal protection of UST. Considering the present management status of UST in Korea, inspection and management criteria of UST should be accomplished in term of contamination protection of leakage, and flexible regulation act should be introduced for each specific site.

• 한국응용과학기술학회지
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• 제29권1호
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• pp.88-94
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• 2012

순환전압전류법을 사용하여 전류-전압 곡선을 측정하였다. 전기화학적 특성과 금속의 표면상태간의 관계는 전자현미경(SEM)을 사용하여 조사하였다. 그리고 순환전압전류법에 의한 전기화학적 측정은 3 전극 시스템을 사용하였다. 측정 범위는 초기 포텐셜에서 -1350 mV까지 환원시키고, 연속적으로 1650 mV까지 산화시키고, 다시 초기지점으로 환원시켜 측정하였다. 스캔속도는 50, 100, 150, 200 및 250 mV/s를 선정하였다. 그 결과, 부식억제로 모노에탄올아민(MEA)을 사용하여 금속의 C-V 특성은 순환전압전류법으로부터 산화 전류에 기인한 비가역 공정으로 나타났다. 부식억제제로 MEA을 사용하였을 경우에는 전해질의 농도가 증가할수록 확산계수가 감소하는 경향을 나타내었다. 그리고 구리의 SEM 이미지를 보면, 전해질 농도를 증가시키면 표면부식은 증가하였다. 부식억제제로 $1.0{\times}10^{-3}M$ MEA를 첨가시키면, 전해질 농도 0.1 N의 경우 확산계수가 상대적으로 커서 부식억제 효과가 적었다.

• 한국폐기물자원순환학회지
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• 제35권7호
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• pp.640-646
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• 2018

Biomass-fired power plants produce electricity and heat by burning biomass in a boiler. However, one of the most serious problems faced by these plants is severe corrosion. In biomass boilers, corrosion comes from burnt fuels containing alkali, chlorine, and other corrosive substances, causing boiler tube failures, leakages, and shorter lifetimes. To mitigate the problem, various approaches implying the use of additives have been proposed; for example, ammonium sulfate is added to convert the alkali chlorides (mainly KCl) into the less corrosive alkali sulfates. Among these approaches, the high temperature corrosion prevention technology based on ammonium sulfate has few power plants being applied to domestic power plants. This study presents the results obtained during the co-combustion of wood chips and waste in a circulating fluidized bed boiler. The aim was to investigate the characteristics of pollution load in domestic biomass power plants with ammonium sulfate injection. By injecting the ammonium sulfate, the KCl content decreased from 68.9 to 5 ppm and the NOx were reduced by 18.5 ppm, but $SO_2$ and HCl were increased by 93.3 and 68 ppm, respectively.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2006년도 추계학술발표회 초록집
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• pp.84-84
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• 2006

• 문화기술의 융합
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• 제8권6호
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• pp.727-732
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• 2022

도시철도 지하구조물에서 중요한 열화 중 하나인 철근부식은 철근의 부피 팽창에 의해 콘크리트의 피복층의 균열 또는 표면박리, 박락 등을 초래하여 철근콘크리트 구조물의 사용성과 안전성이 저하된다. 본 연구에서는 부식환경에서의 도시철도 지하박스 구조물을 대상으로 철근부식으로 인한 콘크리트 피복층의 균열발생 위치에서 철근의 팽창율을 측정하고 이를 바탕으로 철근부식으로 인한 콘크리트 피복층 들뜸 및 손상에 대한 분석을 수행하였다. 부식된 철근의 방사형 변위 분포 모델을 산출하고 기존 제안식과 비교, 분석하였다. 또한 대표 단면을 대상으로한 수치해석(역해석)을 수행하여 부식철근의 방사형 변위장에 의한, 철근의 불균일한 부식팽창을 해석모델에 적용하였다. 수치해석 결과를 바탕으로 철근부식율 진전에 따른 철근콘크리트 구조물의 균열 및 피복층 박리의 영향을 해석적으로 도출하고 현장 시료와의 비교를 통해 수치모델의 적정성을 입증하였다.

• Corrosion Science and Technology
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• 제22권6호
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• pp.419-428
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• 2023

Seawater has been used to cool devices in nuclear power plants. However, the pipes used to transport seawater are vulnerable to corrosion; hence, the inner side of pipelines is coated with an epoxy layer as prevention. Upon coating damage, the pipe becomes exposed, and corrosion progresses. The major cause is widely known as cavitation corrosion, causing the degradation of mechanical properties. In this study, corroded specimens were prepared using cavitation and immersion methods to clarify the degradation trend of mechanical properties with corrosion. Three different types of epoxy coatings were used, and accelerated cavitation procedures were composed of amplitudes of 15 ㎛, 50 ㎛, and 85 ㎛ for 2 h, 4 h, and 6 h. The immersion periods were 3 and 6 weeks. We conducted instrumented indentation tests on all degradation samples to measure mechanical properties. The results showed that higher cavitation amplitudes and longer cavitation or immersion times led to more degradation in the samples, which, in turn, decreased the yield strength. Of the three samples, the C coating had the highest resistance to cavitation and immersion degradation.

• Journal of Advanced Marine Engineering and Technology
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• 제17권1호
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• pp.55-65
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• 1993

Galvanic protection method is one the cathodic protection methods and is mostly used for corrosion prevention of heat exchangers and ship's hull. In this paper, it was investigated that how cathodic potential distribution was varied with according to the bare and painted steel plates in case of galvanic anode protection. The results obtained above were as follows. 1. Cathodic potential distribution of a painted steel plate was smoothed than that of the bare steel plate all over the cathodic surface area. 2. It was shown that polarization potential of the bare steel plate was somewhat shifted to negative potential, on the contrary that of the painted steel plate was somewhat shifted from negative potential to positive potential as time gone by beginning of galvanic anode method. 3. The applied current density in order to maintain constant protection potential(-770mv SCE) in the painted steel plate was less than that of the bare steel plate because of the high resistance polarization of the painted steel plate. 4. It was suggested that required number and life-time of anode for galvanic anode protection could be decided easily with corrosion prevention coefficient obtained by experimental data.

• 한국지하수토양환경학회지:지하수토양환경
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• 제7권4호
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• pp.40-47
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• 2002

본 연구는 유류저장시설에서의 토양오염 방지를 위한 국·내외 관련 시설과 기술 조사 및 관련 법규정 검토를 통해 국내 시설의 현황과 문제점을 도출하고 토양오염 방지조치시설의 기준을 구체화하거나 보완 또는 개선하여 보다 효과적인 토양오염 방지책을 제시하고자 하였다. 부식산화 방지를 위해 저장탱크는 강철-클래드 탱크, 내부 라이닝 탱크 또는 이중벽 탱크를 사용하고 배관은 내부식성 물질로 만든 배관을 사용하는 것이 비용경제적이며 효율적이라고 사료된다. 흘림방지를 위해 주유기 Sump를 설치할 필요가 있으며, 넘침방지 시설의 보호를 위해 유류의 주입방식을 가압식 주입에서 자연 유하식 주입으로 변경할 필요가 있다. 모든 탱크 및 배관 관련 시설은 저장물질의 누출여부를 확인할 수 있도록 자동누출측정기기, 증기 감지시설, 지하수 감시시설, 또는 이중벽 감시시설 등 저장물질의 누출여부를 확인할 수 있도록 한가지 이상의 모니터링 시설을 갖추어야 할 필요가 있는 것으로 나타났다.