The use of current/voltage curves for the study of localized corrosion and passivity breakdown on stainless steels in chloride media

Wilde, B. E.; Williams, E.

doi:10.1016/0013-4686(71)85151-4

Cited by 176 publications

(68 citation statements)

References 22 publications

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“…It represents the condition under which the dissolving pit does not have sufficient overpotential to dissolve rapidly enough to prevent dilution of the pit solution by diffusion. Although first proposed in 1963 [4], the utility of E rp as a stability criterion was a matter of intense debate [5][6][7][8][9]. Its apparent dependence on experimental parameters [7][8][9][10] led to its abandonment for many years as it was seen as not being a reliable material property.…”

Section: Introductionmentioning

confidence: 99%

“…Although first proposed in 1963 [4], the utility of E rp as a stability criterion was a matter of intense debate [5][6][7][8][9]. Its apparent dependence on experimental parameters [7][8][9][10] led to its abandonment for many years as it was seen as not being a reliable material property. Extensive work from several groups [11][12][13][14][15][16] showed that when a sufficiently large anodic charge was passed during localized corrosion, the repassivation potential attains a value which is independent of charge passed for pit growth.…”

Section: Introductionmentioning

confidence: 99%

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Effects of environmental factors on key kinetic parameters relevant to pitting corrosion

Woldemedhin

Srinivasan

Kelly

2015

J Solid State Electrochem

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Experiments using stainless steel artificial pit (leadin-pencil) electrodes in ferric chloride and lithium chloride solutions were performed in order to determine the effects of key environmental factors such as chloride concentration and pH of the bulk solution on the central parameters utilized to characterize the pitting phenomenon-the repassivation potential E rp and the pit stability product under a salt film (i· x) saltfilm . For all the stainless steel alloys studied, a relative independence of the E rp to the pit depth was observed once sufficient anodic charge had been passed. The pit stability product under a salt film was seen to be largely insensitive to the pH of the bulk solution. E rp , on the other hand, was fairly independent of bulk pH only at the lower chloride concentrations of both lithium chloride and ferric chloride solutions. The two parameters were affected differently by variation in the chloride concentration of the bulk solutions. Increasing the chloride concentration resulted in a decrease in the value of (i·x) saltfilm for all alloys in both solutions. In ferric chloride, the value of E rp increased with increasing chloride concentration for Custom 465 and the austenitic steels, whereas it decreased across the same range for 17-4 pH. These trends were explained qualitatively using solution conductivity and alloying composition arguments. Finally, the results obtained from this study allowed for a rationalization of the phenomenology, enabling a method of measurement of the diffusion coefficient and the concentration at saturation of the Bstainless steel cation^within the pit, both of which agreed well with values obtained from the existing literature.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of environmental factors on key kinetic parameters relevant to pitting corrosion

Woldemedhin

Srinivasan

Kelly

2015

J Solid State Electrochem

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“…14,15 This happens because the critical pH can be maintained with lower current density since transport is more difficult as a pit deepens. According to Galvele's detailed description of this phenomenon, a critical value of x · i is required to achieve sufficient pit acidification for pit growth to continue, where x is pit depth and i is current density.…”

Section: Discussionmentioning

confidence: 99%

“…13 However, the utility of the repassivation potential has been questioned because of evidence showing that it depends strongly on experimental parameters such as the potential scan rate and the charge passed between pit initiation and the point of reversal scanning direction. 14,15 Studies of pits in thin metallic films on inert substrates have shown that, in contrast to pits in bulk samples, the repassivation potential is a reproducible and meaningful value because there is no increasing dimension to result in an increasing diffusion path or ohmic potential drop. 16,17 Pits in thin films grow in a 2-D fashion with a constant current density and repassivate at the potential at which the current density is so low that the critical pit environment cannot be maintained.…”

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confidence: 99%

On the Pitting Resistance of Sputter‐Deposited Aluminum Alloys

Frankel

Newman²,

Jahnes

et al. 1993

J. Electrochem. Soc.

124

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The pitting behavior of sputter-deposited Al binary alloy thin films was studied. Pitting and repassivation potentials were determined in 0.1M NaCl for samples in freshly deposited and air-aged states. Aging for several years in laboratory air increased the pitting potential for some of the alloy systems but had no effect on others. The repassivation potentials, meaningful values for pits in thin films, were found to be very close to the pitting potentials of freshly-deposited films for many alloy systems. Stable pits initiate in these Al binary alloys at potentials just above the value at which they would repassivate, indicating that pit growth considerations control the pitting process. By determining the pit anodic current density just before passivation it is shown that alloying improves pitting resistance through a reduction in the ability of pits to maintain the critical local environment necessary for growth. The influences of alloying on the passive film chemistry and on the tendency of the metal to repassivate (depassivation pH) are secondary in nature.Sputter-deposited supersaturated Al binary alloys have been shown to exhibit remarkable pitting resistance in chloride solutions.

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“…Wilde showed that E R of ferritic stainless steel decreased (became more negative) with increasing values of the current density at which the potential scan direction was reversed. 4,5 So deeper pits apparently repassivated at lower potentials. In contrast, the repassivation potential for pits in Al seemed to be relatively independent of the extent of prior pit growth for a limited number of experiments.…”

Section: 2mentioning

confidence: 98%

Repassivation of Pits in Aluminum Thin Films

Frankel

Scully

Jahnes

1996

J. Electrochem. Soc.

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The effect of metal film thickness on repassivation of pits in sputter-deposited Al thin films was investigated in chloride solutions. The repassivation potential and the critical current density, which is the pit current density below which pits stop growing, were determined for pits in Al thin films ranging from 100 Ǻ to 43 µm in thickness. The repassivation potential first decreased as thickness increased from 100 to 4350 Ǻ, and then increased as the film thickness increased further. This behavior was found to be a consequence of the pit currentdensity/potential relationship. The critical current density, a more informative parameter, decreased for increasing metal film thickness, even when the repassivation potential increased. The critical current density is the minimum current density needed to maintain the critical pit environment and prevent repassivation. The repassivation potential for a given metal film thickness is the potential at which the pit current density drops below the critical value. Masstransport and ohmic resistance both increase as the metal film thickness increases, but the former enhances pit stability and the latter destabilizes pitting in this system. Pit repassivation, and thus stability, are strongly influenced by mass-transport considerations for pits in very thin pits, even though dissolution at low potentials is not under pure mass-transport control. Ohmic effects become increasingly important as the film thickness increases.

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The use of current/voltage curves for the study of localized corrosion and passivity breakdown on stainless steels in chloride media

Cited by 176 publications

References 22 publications

Effects of environmental factors on key kinetic parameters relevant to pitting corrosion

Effects of environmental factors on key kinetic parameters relevant to pitting corrosion

On the Pitting Resistance of Sputter‐Deposited Aluminum Alloys

Repassivation of Pits in Aluminum Thin Films

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