• 제목/요약/키워드: Electrochemical evaluation

검색결과 320건 처리시간 0.027초

재활성화 분극시험에 의한 Cr-Mo-V강의 시효열화 손상 평가 (An Evaluation of Aging Degradation Damage for Cr-Mo-V Steel by Electrochemical Potentiokinetic Reactivation Test)

  • 권일현;나성훈;송기욱;유효선
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 춘계학술대회논문집A
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    • pp.49-54
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    • 2000
  • Cr-Mo-V steel is widely used as a material for the turbine structural component in fossil power plants. It is well known that this material shows the various material degradation phenomenons such as temper embrittlement, carbide coarsening. and softening etc. or ins to the severe operation conditions as high temperature and high pressure. These deteriorative factors cause tile change of mechanical properties as reduction of fracture toughness. Therefor it is necessary to evaluate tile extent of degradation damage for Cr-Mo-V steel in life assessment of turbine structural components. In this paper. the electrochemical potentiokinetic reactivation(EPR) test in $50wt%-Ca(NO_3)_2$ solution is performed to develop the newly technique for degradation damage evaluation of Cr-Mo-V steel. The results obtained from the EPR test are compared with those in small punch(SP) tests recommended by semi-nondestructive testing method using miniaturized specimen. The evaluation parameters used in EPR test are tile reactivation current density$(I_R)$ and charge$(Q_{RC})$ reactivation rate$(I_R/I_{Crit},\;Q_R/Q_{Crit})$. The results suggest that $I_R/I_{Crit}$ in these parameters shows a good correlation with SP test results.

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A Unified Potentiostat for Electrochemical Glucose Sensors

  • Sohn, Ki-Sung;Oh, Seok-Jae;Kim, Eui-Jin;Gim, Jeong-Min;Kim, Nam-Soo;Kim, Yeong-Seuk;Kim, Jong-Won
    • Transactions on Electrical and Electronic Materials
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    • 제14권5호
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    • pp.273-277
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    • 2013
  • A unified potentiostat circuit for both $O_2$- and $H_2O_2$- based electrochemical glucose sensors was proposed and its function was verified by circuit simulations and measurement results of a fabricated chip. This circuit consisted of an operational amplifier, a comparator and current mirrors. The proposed circuit was fabricated with a $0.13{\mu}m$ thick oxide CMOS process and an active area of $360{\mu}m{\times}100{\mu}m$. The measurements revealed an input operation range from 0.5 V to 1.6 V in the $H_2O_2$- based bio-sensor and from 1.7 V to 2.6 V in the $O_2$- based bio-sensor with a supply voltage of 3.3 V. The evaluation results showed that the proposed potentiostat circuit is suitable for measuring the electrochemical cell currents of both $O_2$- and $H_2O_2$- based glucose sensors.

이온 마이그레이션 발생에 대한 수분온도의 영향 (Effect of Water Temperature on Generation of Ion Migration)

  • 이덕보;김정현;강수근;김상도;장석원;임재훈;유동수
    • 한국신뢰성학회지:신뢰성응용연구
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    • 제5권2호
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    • pp.261-272
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    • 2005
  • In evaluation of electronic reliability on the PCB(Printed Circuit Board), electrochemical migration is one of main test objects. The phenomenon of electrochemical migration occurs In the environment of the high humidity and the high temperature under bias through a continuous aqueous electrolyte. In this paper, the generating mechanism of electrochemical migration is investigated by using water droll acceleration test under various waters. The waters used in the water drop test are city water, distilled water and ionic water. It found that the generated velocity of electrochemical migration depended on the temperature of water and the electrolyte quantity which included in the various waters.

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Electrochemical Evaluation on Corrosion Resistance of Anti-corrosive Paints

  • Moon, Kyung-Man;Lee, Myung-Hoon;Kim, Yun-Hae
    • Journal of Advanced Marine Engineering and Technology
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    • 제33권3호
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    • pp.387-394
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    • 2009
  • It has been observed that coated steel structures are rapidly deteriorated than designed lifetime due to acid rain caused by air pollution etc.. Therefore improvement of corrosion resistance of anti-corrosive paint is very important in terms of safety and economic point of view. In this study corrosion resistance for five kinds of anti-corrosive paints including acryl, fluorine and epoxy resin series were investigated with electrochemical methods such as corrosion potential, polarization curves, impedance and cyclic voltammogram measurements etc.. There were somewhat good relationships between values measured by electrochemical methods such as corrosion current density obtained by cathodic and anodic polarization curves, value of impedance estimated with AC impedance, and polarization resistance on the cyclic voltammogram, for example, corrosion current density was decreased with increasing of values of impedance and polarization resistance on the cyclic voltammogram. However their relationships between corrosion current density and corrosion potential were not well coincided each other. Consequently it is considered that although a corrosion potential of F101 of fuoric resin series shifted to negative direction than other anti-corrosive paints, its corrosion resistance, indicating on the cathodic and anodic polarization curves, AC impedance curves and cyclic voltammogram, was the most superior to other paints, whereas A100 containing arcylic resin showed a relatively poor corrosion resistance compared to other paints.