Stochastic Approach to the Initiation of Pitting Corrosion

Balkwill, Peter; Westcott, C.; Williams, Dudley

doi:10.4028/www.scientific.net/msf.44-45.299

Cited by 13 publications

(5 citation statements)

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“…For the Al alloy in phosphate solution, the power level of the potential noise was very high, and the slope of power spectrum was -8.33 dB/decade ( Figure 2[a]). So, according to these findings reported in the literature, 5,24 phosphate could not inhibit localized corrosion of Al 7075-T76 in chloride media. Results of the electrochemical polarization scan and immersion test (Tables 1 and 2) verified this conclusion.…”

Section: Discussionsupporting

confidence: 82%

“…In phosphate solution, potential of the Al alloy fluctuated very frequently, and the fluctuation level was high mainly in the high-frequency band, as shown in Figure 7(a), where the standard deviation values of the detail signals at every scale could be fitted on a line. It has been found that the frequency of occurrence of electrochemical transients has been related directly to the probability of forming a propagating macropit, 24 and is an implication that could be the basis of a practical and simple method to quantify pitting resistance of the Al alloy. For the Al alloy in phosphate solution, the power level of the potential noise was very high, and the slope of power spectrum was -8.33 dB/decade ( Figure 2[a]).…”

Section: Discussionmentioning

confidence: 99%

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Analysis of Electrochemical Noise with Wavelet Transform

Liu¹,

Wang²,

Huang³

et al. 2001

CORROSION

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Wavelet transform is a new technique to analyze signals and images, and it can reveal the local and global features of signal and image from different aspects. In this study, the electrochemical potential noises measured on Al 7075-T76 (UNS A97075) in 3.5% sodium chloride (NaCl) solution containing different inhibiting pigments were analyzed with a wavelet transform from time-frequency analysis and detection of abrupt transition. Wavelet transform decomposed the electrochemical noise signal into a series of components in time-frequency domain to reveal the characteristics of the potential noise in detail. It was convenient to distinguish the inhibiting effects of these pigments and corrosion processes on the surface. The finding agreed with the results of electrochemical polarization and immersion studies. The accurate onset time of localized corrosion was detected by examining the module maximums of wavelet transform coefficients, which represented the signal characteristic.

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Section: Discussionsupporting

confidence: 82%

Section: Discussionmentioning

confidence: 99%

Analysis of Electrochemical Noise with Wavelet Transform

Liu¹,

Wang²,

Huang³

et al. 2001

CORROSION

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“…10,17 Williams and coworkers realized that the stochastic approach set out by Shibata could be extended to describe metastable pits, since large ensembles of metastable pits can be generated easily. 88,98,99 Metastable pits are assumed to nucleate randomly in time and space at a frequency λ (cm -2 s -1 ). Each pit has a probability µ(cm -2 s -1 ) of dying, unless it survives beyond a critical age τ C (S) at which point it becomes stable.…”

Section: Stages Of Pittingmentioning

confidence: 99%

Pitting Corrosion of Metals: A Review of the Critical Factors

Frankel

1998

J. Electrochem. Soc.

1,679

786

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Pitting corrosion is localized accelerated dissolution of metal that occurs as a result of a breakdown of the otherwise protective passive film on the metal surface. This paper provides an overview of the critical factors influencing the pitting corrosion of metals. The phenomenology of pitting corrosion is discussed, including the effects of alloy composition, environment, potential, and temperature. A summary is then given of studies that have focused on various stages of the pitting process, including breakdown of the passive film, metastable pitting, and pit growth.

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“…A further complication can arise, viz., stable pitting preceded by metastable pit formation, which is indicated by anodic current spikes that form micrometer size pits, often at a sub-lattice or array of non-metallic inclusions that act as weak sites in the passive film (10,11). Moreover, it is well known that there is a statistical correlation between metastable and stable pitting (12) and that the frequency of metastable pitting increases with increasing applied potential (11)(12)(13)(14)(15). A trigger mechanism has also been proposed (16).…”

Section: Introductionmentioning

confidence: 99%

Nonequilibrium collective phenomena in the onset of pitting corrosion

2009

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Nonequilibrium collective phenomena and effects of nonlinear pattern formation play the crucial role in the onset of pitting corrosion on stainless steels. Such materials are naturally protected by the oxide layer covering their surface. The onset of pitting corrosion involves the development of microscopic metastable pits, each persisting for about a second. As proposed in our publications and confirmed in subsequent experiments, sudden transition to active corrosion results from chain reproduction of metastable pits on the stainless steel surface leading to an autocatalytic explosion.

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Stochastic Approach to the Initiation of Pitting Corrosion

Cited by 13 publications

References 0 publications

Analysis of Electrochemical Noise with Wavelet Transform

Analysis of Electrochemical Noise with Wavelet Transform

Pitting Corrosion of Metals: A Review of the Critical Factors

Nonequilibrium collective phenomena in the onset of pitting corrosion

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