• Title/Summary/Keyword: 상대부식전류

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Effects of Torsional Stress on the Corrosion Characteristics in the Rotor Assembly of Marine Diesel Engine Supercharger (선박용 디젤엔진 과급기 로터 접합체의 부식특성에 미치는 비틀림응력의 영향)

  • Jo, S.K.;Kong, Y.S.;Kim, Y.D.
    • Journal of Power System Engineering
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    • v.9 no.1
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    • pp.50-56
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    • 2005
  • The corrosion experiment was performed for 120 hours on the specimens in the natural seawater tank with four steps of the loaded torsional stress. The surface corrosion pattern of SCM440 area was showed global corrosion and narrow pitting, that was cause by galvanic corrosion between friction welded IN713LC and SCM440. But corrosion does not proceeded from IN713LC area. Initially, the average relative electrode potential and corrosion current were decreased suddenly, by and large, it was stabilized gradually tend to decreasing with the elapse of the immersion time. The corrosion rate was decreased by increasing the load stress, but 200 MPa specimen was showed most large value.

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The Effects of pH on the Corrosion Characteristics in Dissimilar Friction Welded Zone of IN713LC-SCM440 (IN713LC-SCM440 이종재 마찰용접부의 부식특성에 미치는 pH의 영향)

  • JO SANG-KEUN;KONG YU-SIK;KIM YOUNG-DAE
    • Journal of Ocean Engineering and Technology
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    • v.19 no.2 s.63
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    • pp.53-59
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    • 2005
  • The effect of pH on the corrosion characteristics in the dissimilar friction welded zone of IN713LC-SCM440 in the loaded torsional stress was studied. The corrosion experiment was performed for 120 hours on the specimens with five steps of pH. The surface corrosion pattern of the SCM440 area showed global corrosion and narrow pitting, which was caused by galvanic corrosion between friction welded IN713LC and SCM440, but corrosion did not proceeded from the IN713LC area. The average relative electrode potential gradually tends to decrease with the elapse of the immersion time in the acidity area. The average corrosion current also gradually tend to decrease The corrosion rate showed a larger value when the average relative electrode potential was higher and the average relative current was lower. The corrosion rate showed a larger value when the average relative electrode potential was higher in the acidity area, and it showed large when the average relative electrode potential was lower in the alkalinity area.

On Corrosion Behaviors in Welded Zone of API 5L-X65 Steel for Natural Gas Transmission (천연가스 수송용 API 5L-X65강 용접부의 부식거동에 관한 연구)

  • JO SANG-KEUN;SONG HAN-SEOP;KONG Yu-SIK;KIM YOUNG-DAI
    • Journal of Ocean Engineering and Technology
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    • v.18 no.5
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    • pp.50-56
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    • 2004
  • This study is on the constant-current stress corrosion test, related to the load stress, in both the welded and non-welded zones of high tensile strength steel that is used for natural gas transmission. The surface corrosion pattern of the welded zone of API 5L-X65 specimens for natural gas transmission showed general corrosion and narrow pitting, and the pitting was increased with load stress. Initially, the average relative electrode potential and the average relative current of the high tensile strength steel, used for natural gas transmission specimens, were decreased rapidly, and the average relative electrode potential was higher and the average relative current was lower in welded zone, compared to base metal. The average relative electrode potential was decreased with load stress, and the average relative current was somewhat increased by increasing the load stress. The corrosion rate was less in welded zone, compared to base metal, and the corrosion rate was decreased by increasing the load stress.

Relative Corrosion Environment Conditions of Steel Box Members Examined by Corrosion Current Measurement (부식전류 평가를 통한 강박스 부재의 상대적 부식환경 평가)

  • Jin, Yong-Hee;Ha, Min-Gyun;Jeong, Young-Soo;Ahn, Jin-Hee
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.24 no.6
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    • pp.171-179
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    • 2020
  • In this study, a local corrosion environment monitoring was conducted using steel box specimen fabricated to be the same as actual steel bridge members. The steel box specimen that obtained the same corrosion environment as a steel bridge was classified into the upper plate, bottom plate and web plate. Atmospheric corrosion monitoring sensors(ACM sensors) were installed in each corrosion monitoring member of a steel box specimen to measure the corrosion current and examine time of wetness for each monitoring member. The time of wetness and accumulated corrosion current of each monitoring member were calculated from the measured corrosion current using ACM sensors. The corrosion environment that appeared for each of the steel box members was evaluated from monitoring corrosion environment data as the corrosion current, time of wetness, mean corrosion depth of each monitoring member. Additionally, the atmospheric corrosion environment monitoring was also conducted to compare with the local corrosion environment of steel box members. From these local corrosion environment monitoring for the steel box specimen, the relationship between the relative corrosion environment and mean corrosion depth of each steel box member was examined.

Electrochemical Characterization of Stainless Steel in Ethanolamine Solution Containing an Alkyl Group using Cyclic Voltammetry (순환전압전류법에 의한 알킬기를 함유한 에탄올아민용액에서 스테인리스의 전기화학적 특성)

  • Park, Keun-Ho
    • Journal of the Korean Applied Science and Technology
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    • v.31 no.1
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    • pp.66-73
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    • 2014
  • In this work, the current-voltage curves for stainless steel in the ethanolamine solution containing alkyl group were measured using the conventional three electrodes of cyclic voltammetry. Stainless steel as working electrode, Ag/AgCl electrode as reference electrode and Pt wire as counter electrode were used respectively. As a result, the C-V characteristics of stainless steel were to be for an irreversible process due to the oxidation current from cyclic voltammogram, using N-ethylethanolamine and N,N-dimethylethanolamine solutions. Effective diffusivity of corrosion inhibitors was decreased with increasing concentration. It was found from SEM images of the metal that the electrolyte (specific name ?)(0.5 N) as corrosion inhibitor was added into a N, N-diethylethanolamine solution ($1.0{\times}10^{-3}M$) containing copper and nickel, the corrosion inhibiting effect was enhanced.

Evaluation of Relative Corrosion Rate depending on Local Location and Installation of Structural Member in Steel Water Gate (강재 수문의 부재 위치 및 설치 방향에 따른 상대 부식속도 평가)

  • Ha, Min-Gyun;Jeong, Young Soo;Park, Seung hun;Ahn, Jin-Hee
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.23 no.7
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    • pp.16-24
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    • 2019
  • The corrosion amounts of steel structures can be different depending on their installation condition and height. Thus, their corrosion maintenance should be considered depending on installation conditions of local structural members. In this study, an atmospheric exposure test was conducted to evaluate the corrosion amount and the corrosion rate depending on the installation condition and height of a steel water gate using monitoring steel plates and corrosion environment measuring sensors. The mean corrosion depth was evaluated using the weight loss method and the galvanic corrosion current was measured by corrosion environment measuring sensors. Local corrosion rate of local structural member in steel water gate was estimated using measured mean corrosion depths and galvanic corrosion currents. From this measurement results, the corrosion damage in horizontal member of the cross beam was highly evaluated than those of other structural member as skin plate, etc. The relative difference in the corrosion rate of a local structural member could be highly affected by local corrosion environments of steel water gate members. Therefore, an appropriate maintenance method should be considered for local corrosion damages of local structural members determined by local corrosion environments of a steel water gate.

고온고습 환경에서 태양전지 모듈의 성능 향상을 위한 연구

  • Kim, Ju-Hui;O, Won-Uk;Bae, Su-Hyeon;Kim, Dong-Hwan;Park, No-Chang
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.494.1-494.1
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    • 2014
  • 태양광은 세계적으로 유망한 에너지 중의 하나이며, 태양광 모듈은 실제 옥외 조건에 따라 다르지만 장기 신뢰성과 수명을 보장하기 위해 최소 20년 이상을 안정적으로 작동될 필요성이 있다. 하지만 실제 태양전지는 옥외에 장기 노출됨에 따라 성능이 저하되며, 그 원인으로는 셀 균열, 부식, 접착 강도 손실 및 박리, 그리고 변색 등이 있다. 본 논문에서는 부식으로 인한 성능 저하를 완화하기 위해 희생금속을 이용하여 태양전지 모듈의 성능 향상에 대해 연구하였다. 태양전지는 4 cell 결정질 실리콘 태양전지 미니 모듈을 이용하였고, 희생금속의 영향을 확인하기 위해 두 종류의 시료를 준비하였다. 한 시료에는 Al 희생금속을 태양전지 리본 위에 부착하였으며, 나머지 한 시료는 비교 시료로 Al 희생금속을 부착하지 않았다. 시료는 $85^{\circ}C$ 85%의 상대습도인 고온고습 조건에서 2500시간을 진행하였다. 그리고 2500시간의 고온고습 시험이 진행된 시료의 전기적 특성을 분석하였다. 시험 결과, 희생금속이 없을 경우 28.8%의 출력 저하가 있었으며, 희생금속이 있을 경우 19.3%의 출력 저하가 확인되었다. 또한, 희생금속이 없을 경우, 충실도는 21.5% 감소하였으며, 단락전류 역시 약 6% 정도 감소하였다. 반면, 희생금속이 있을 경우, 충실도는 16.1%로 감소하였고, 단락전류는 거의 변화가 없었다.

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A Study on the Electrochemical Characterization of Stainless Steel in Triethanolamine Solution (트리에탄올아민용액에서 스테인리스강의 전기 화학적 특성)

  • Park, Jin-Hyeog;Lee, Jong-Ho;Park, Keun-Ho
    • Journal of the Korean Applied Science and Technology
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    • v.32 no.2
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    • pp.275-280
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    • 2015
  • In this study, the current-voltage curves for stainless steel in the triethanolamine(TEA) solution was measured using the conventional three electrodes of cyclic voltammetry. Stainless steel as working electrode, Ag/AgCl electrode as reference electrode and Pt wire as counter electrode were used respectively. As a result, the C-V characteristics of stainless steel were to be for an irreversible process due to the oxidation current from cyclic voltammogram, using triethanolamine solutions. Effective diffusivity of corrosion inhibitors was decreased with increasing concentration. And the concentration of 0.5 N $NaClO_4$, $2.5{\times}10^{-3}M$ TEA solution when the corrosion inhibition effect is most great, and 1.5 N $NaClO_4$, $1.0{\times}10^{-3}M$ TEA solution, the lowest corrosion inhibition effect.

Degradation of a nano-thick Au/Pt bilayered catalytic layer with an electrolyte in dye sensitized solar cells (염료감응태양전지의 Au/Pt 이중 촉매층의 전해질과의 반응에 따른 열화)

  • Noh, Yunyoung;Song, Ohsung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.6
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    • pp.4013-4018
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    • 2014
  • A 0.45 $cm^2$ DSSC device with a glass/FTO/blocking layer/$TiO_2$/N719(dye)/electrolyte/50 nm-Pt/50 nm-Au/FTO/glass was prepared to examine the stability of the Au/Pt bilayered counter electrode (CE) with electrolyte and the energy conversion efficiency (ECE) of dye-sensitized solar cells (DSSCs). For comparison, a 100 nm-thick Pt only CE DSSC was also prepared using the same method. The photovoltaic properties, such as the short circuit current density ($J_{sc}$), open circuit voltage ($V_{oc}$), fill factor (FF), and ECE, were checked using a solar simulator and potentiostat with time after assembling the DSSC. The microstructure of the Au/Pt bilayer was examined by optical microscopy after 0~25 minutes. The ECE of the Pt only CE-employed DSSC was 4.60 %, which did not show time dependence. On the other hand, for the Au/Pt CE DSSC, the ECEs after 0, 5 and 15 minutes were 5.28 %, 3.64 % and 2.09 %, respectively. The corrosion areas of the Au/Pt CE determined by optical microscopy after 0, 5, and 25 minutes were 0, 21.92 and 34.06 %. These results confirmed that the ECE and catalytic activity of Au/Pt CE decreased drastically with time. Therefore, a Au/Pt CE-employed DSSC may be superior to the Pt only CE-employed one immediately after integration of the device, but it would degrade drastically with time.