• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제10권S_4호
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• pp.181-187
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• 2001

This study was carried out to measure the variations of potential and current density with polymers. The results were particularly examined to identify the influences on potential and rate of various factors including temperature and pH. The Tafel slope for anodic dissolution was determined by the polarization effect depending on these conditions. The optimum conditions were established for each case. The second anodic current density peak and maximum current density were designated as the relative polarization sensitivity$(I_r/I_f)$. The mass transfer coefficient value$(\alpha)$ was determined with the Tafel slope for anodic dissolution based on the polarization effect with optimum conditions.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제4권1호
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• pp.43-50
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• 2000

In this study, experiments were carried out to measure the variations in the corrosion potential and current density of polarization curves using polycarbonate. The results were particularly examined to identify the influences affecting the corrosion potential including various conditions such as temperature, pH, catalytic enzyme, and salt. The lines representing the active anodic dissolution were only slightly shifted in the potential direction by temperature, pH, enzyme, and salt. The tafel slope for the anodic dissolution was determined based on the polarization effect with various conditions. The slope of the polarization curves describing the active-to-passive transition region were noticeably shifted in direction. Also, from the variation in the conditions, the optimum conditions were established for the most rapid transformation, including temperature, pH, corrosion rate, and resistance of corrosion potential. The second anodic current density peak and maximum passive current density were designated as the critical corrosion sensitivity(Ir/If). The value of Ir/If was then used in measuring the extent of the critical corrosion sensitivity of the polycarbonate. The potentiodynamic parameters of the corrosion were obtained using a Tafel plot.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.74.1-74.1
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• 2010

수치해석을 이용하여 형상 및 운전 조건에 따른 금속공기전지의 전기화학적 성능 변화를 조사하였다. 저전류밀도 영역에서의 전지 성능은 농도손실에 의한 영향이 미미하므로 활성화 손실과 저항손실만을 고려한 수치해서 모델을 적용하였다. 지배방정식은 전기전도식을 이용하였으며 전극 표면의 활성화손실을 모사하기위해 아연극(음극)에는 butler-volmer식을, 공기극(양극)에는 tafel식을 적용하였다. 실험결과와의 비교/분석을 통하여 수치해석 모델의 타당성을 검증하였다. 또한, 아연극과 공기극 사이의 간격과 전해질 농도 변화에 따른 아연공기전지 내부에서의 전류밀도분포를 조사하였으며, 분극곡선을 통해 전기화학적 성능을 평가하였다.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제4권3호
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• pp.165-171
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• 2000

Experiments were carried out to measure variations in the oxidation potential and current density using the polarization curves of polycarbonate. The results were then examined to identify the influences affecting the oxidation potential related to various conditions, such as temperature, pH, and oxydase(citrate and lipase). The lines representing the active anodic and cathodic dissolution shifted only slightly in the potential direction relative to temperature, pH, and the effect of the enzyme. The Tafel slope for the anodic and cathodic dissolution was determined such that the reversibility polarization was indicated as being effected by various conditions. The slope of the polarization curves describing the active-to-passive transition region shifted noticeably in their direction. Also, by varying the conditions, the optimum conditions for the most ready transform were identified, including temperature, pH, oxidation rate, and resistance of oxidation potential. The critical oxidation sensitivity(I(sub)r/I(sub)f) of the anodic current density peak and maximum passive current density was also determined, which is used in measuring the critical corrosion sensitivity of a polycarbonate.

• Corrosion Science and Technology
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• 제20권5호
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• pp.231-241
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• 2021

The objective of this study was to evaluate total current under steady-state conditions for a material undergoing corrosion using the electrochemical frequency modulation (EFM) technique, taking into account the presence of solution resistance and double layer capacitance. The analysis involving linearization of the Tafel curve allowed for the estimation of corrosion parameters. Results showed that the output signal was dependent on fundamental frequencies and their multiples. In addition, the output signal almost manifested itself at frequencies that were sums of fundamental frequencies of the applied sinusoidal signal. The harmonics calculated showed a significant shift from the principal frequency of input signals. The investigation involved the influence of corrosion current and anode-to-cathode Tafel slope ratio on faradaic and non-faradaic currents (including the average and RMS). The model presented showed both qualitative and quantitative improvements over the previously developed EFM technique that ignored the influence of solution resistance and the double layer capacitance while assuming the applied DC potential corresponded to the corrosion potential of the corroding material.

• Journal of Advanced Marine Engineering and Technology
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• 제29권5호
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• pp.519-525
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• 2005

An electrochemical evaluation on the corrosion resistance for heavy anticorrosive paint(DFT:25um) was carried out for 5 kinds of heavy anticorrosive paints such as high solid epoxy(HE), solvent free epoxy(SE). tar epoxy(TE), phenol epoxy(PE). and ceramic epoxy(CE). Corrosion current densities obtained by Tafel extrapolation method from anodic and cathodic polarization curves didn't correspond with the values obtained by AC impedance measurement, however, the values of polarization resistance obtained from the cyclic voltammogram showed a good tendency corresponding well with the values of AC impedance measurement. Futhermore there was a good correlation against the corrosion resistance evaluation between passivity current density of the anodic polarization curve and diffusion limiting current density of the cathodic polarization curve. And corrosion resistance increased with corrosion potential shifting to noble direction. From the results discussed above. HE and CE had a relatively good corrosion resistance than other heavy anticorrosive paints.

• Journal of Advanced Marine Engineering and Technology
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• 제29권5호
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• pp.495-501
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• 2005

Al is a active metal that owes its resistance to a thin, protective, barrier oxide surface layer, which is stable in air and neutral aqueous solution. Thus Al alloys are widely used in architectural trim. cold & hot-water storage vessels and piping. However Al and most of its alloy may corrode with some forms such as pitting corrosion, intergranular corrosion and galvanic corrosion in the case of exposure to various industrial and marine atmosphere. Therefore a correct evaluation of corrosion resistance for their Al and Al alloys may be more important in a economical point of view. In this study. a relative evaluation of corrosion resistance for three kinds of Al alloys such as ALDC2, ALDC3, and ALDC8 series was carried out with electrochemical method. There is a tendency that corrosion potential is shifted to positive or negative direction by alloying components regardless of corrosion resistance. Moreover the data of corrosion properties obtained from cathodic Polarization curve, cyclic voltammogram and AC. DC impedance respectively showed a good correspondence each other against the corrosion resistance but variation of corrosion potential. passivity current density of anodic polarization curve and corrosion current density by Tafel extrapolation and Stern-Geary method didn't correspond with not only each other but also considerably the data of corrosion properties discussed above. Therefore it is suggested that an optimum electrochemical evaluation for corrosion resistance of Al alloy is to calculate the diffusion limiting current density of cathodic polarization curve, impedance of AC or DC and polarization resistance of cyclic voltammogram.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.221-222
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• 2021

Bacterial self-healing concrete is known to improve the durability of concrete by preventing the propagation of microcracks. In the literature, bacteria prevent the corrosion of rebar by inhibiting water transfer through crack, but also can promote the corrosion by acting as an ion acceptor in the rust generation mechanism. Therefore in this study, the electrochemical analysis of bio-filmed rebar was conducted to explore the effects of the self-healing bacteria on the bare rebar without cement composite. As a result of the experiment contradicting trends for Ecorr and Icorr occurred and additional experiment will be conducted in various environments to collect data on the mechanism of corrosion of rebar by bacteria.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2009년도 춘계학술대회 논문집
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• pp.217-218
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• 2009

최근 경량화, 리사이클성, 기기의 소형화, 내환경성 등의 이점을 가지고 있는 알루미늄 합금이 여러 분야서 재인식 되고 있다. 그러나 이런 알루미늄 합금이 부식 환경에 노출 될 경우 음력부식균열이 발생할 수 있게 된다. 이러한 음력부식균열의 발생은 알루미늄의 기계적 특성에 안 좋은 영향을 미치므로 제품의 품질저하, 수명 단축, 효율저하, 재해발생 등 직간접적으로 광범위한 피해를 입게 되기에 부식에 대한 많은 연구가 진행이 되고 있다. 이 중에 고비강도용 알루미늄 압출소재인 Al 6xxx계 합금의 열처리 및 조성 변화에 따른 음력부식 균열의 거동에 대해 연구하였다. 응력부식균열 시험은 SSRT시험으로 많이 하고 있는데, 이 시험은 인장시편을 부식 환경 하에 노출하면서 천천히 일정한 변형속도로 당기는 시험이다. 본 연구에서는 Strain rate를 ${10^{-6}}s^{-1}$ 부식용액은 1M-NaCl + 0.6M-$Na_{2}SO_{4}$ + 0.3%-$H_{2}O_{2}$을 사용하여 시험을 하였다. 그러나 시험에 대한 분석은 Tafel polarization curve, SEM, OMS를 이용하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.49-49
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• 2007

최근 반도체 소자의 고집적화와 나노 (nano) 크기의 회로 선폭으로 인해 기존에 사용되었던 텅스텐이나 알루미늄 금속배선보다, 낮은 전기저항과 높은 electro-migration resistance가 필요한 Cu 금속배선이 주목받게 되었다. 하지만, Cu CMP 공정 시 높은 압력으로 인하여 low-k 유전체막의 손상과 디싱과 에로젼 현상으로 인한 문제점이 발생하게 되었다. 본 논문에서는, $KNO_3$ 전해액의 농도가 Cu 표면에 미치는 영향을 알아보기 위해 Tafel Curve와 CV (cyclic voltammograms)법을 사용하여 전기화학적 특징을 알아보았고 scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray Diffraction (XRD) 분석을 통해 금속표면을 비교 분석하였다.