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Title: Perspective—Localized Corrosion: Passive Film Breakdown vs Pit Growth Stability

Abstract

A debate about the critical step in localized corrosion has raged for decades. Some researchers focus on the composition and structure of the passive film associated with the initial breakdown of the film, whereas others consider that the susceptibility to pitting is controlled by the pit growth kinetics and the stabilization of pit growth. The basis for a unified theory of pitting is presented here in which pit stability considerations are controlling under aggressive conditions (harsh electrolytes and extreme environments and/or susceptible microstructures) and the passive film properties and protectiveness are the critical factors in less extreme environments and/or for less susceptible alloys.

Authors:
 [1];  [1];  [2]
  1. The Ohio State Univ., Columbus, OH (United States)
  2. Univ. of Virginia, Charlottesville, VA (United States)
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Center for Performance and Design of Nuclear Waste Forms and Containers (WastePD)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1388179
Grant/Contract Number:
SC0016584
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of the Electrochemical Society
Additional Journal Information:
Journal Volume: 164; Journal Issue: 4; Journal ID: ISSN 0013-4651
Publisher:
The Electrochemical Society
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Corrosion; passivation; pit growth; pitting

Citation Formats

Frankel, G. S., Li, Tianshu, and Scully, J. R. Perspective—Localized Corrosion: Passive Film Breakdown vs Pit Growth Stability. United States: N. p., 2017. Web. doi:10.1149/2.1381704jes.
Frankel, G. S., Li, Tianshu, & Scully, J. R. Perspective—Localized Corrosion: Passive Film Breakdown vs Pit Growth Stability. United States. doi:10.1149/2.1381704jes.
Frankel, G. S., Li, Tianshu, and Scully, J. R. Fri . "Perspective—Localized Corrosion: Passive Film Breakdown vs Pit Growth Stability". United States. doi:10.1149/2.1381704jes. https://www.osti.gov/servlets/purl/1388179.
@article{osti_1388179,
title = {Perspective—Localized Corrosion: Passive Film Breakdown vs Pit Growth Stability},
author = {Frankel, G. S. and Li, Tianshu and Scully, J. R.},
abstractNote = {A debate about the critical step in localized corrosion has raged for decades. Some researchers focus on the composition and structure of the passive film associated with the initial breakdown of the film, whereas others consider that the susceptibility to pitting is controlled by the pit growth kinetics and the stabilization of pit growth. The basis for a unified theory of pitting is presented here in which pit stability considerations are controlling under aggressive conditions (harsh electrolytes and extreme environments and/or susceptible microstructures) and the passive film properties and protectiveness are the critical factors in less extreme environments and/or for less susceptible alloys.},
doi = {10.1149/2.1381704jes},
journal = {Journal of the Electrochemical Society},
number = 4,
volume = 164,
place = {United States},
year = {Fri Feb 24 00:00:00 EST 2017},
month = {Fri Feb 24 00:00:00 EST 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 3works
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  • Mechanisms for the film growth and breakdown on zircorium and Zircaloy-2 are discussed. Oxidation experiments were carried out on zirconium and Zircaloy- 2 specimens at 300 ts C in 1-atm steam or in aqueous solutions. From the data, the following mechanism for oxide film growth and breakdown is proposed: The growth of the thin interference color film was found to obey a logarithmic growth law and probably is an example of Uhlig's thin film growth law as applied to metal oxidation. After the oxide film darkens and the interference colors disappear, the distribution of the inhomogeneous regions in the filmmore » due to impurities or alloying elements in the metal determines the subsequent behavior of the material. On this basis, the early failure of arc-melted zirconium and the breakaway of Zircaloy-2 below 400 ts C are explained. (D.L.C.)« less
  • Al[sub 3]Ta precipitates act as sites for pit initiation and propagation in Al-Ta alloys. Dynamic imaging microellipsometry was used to measure the change in oxide film thickness and the refractive indexes of the films that form on the precipitates and matrix to examine the role of the precipitates in breakdown. Film formation was measured on an Al-1.5 a/o Ta alloy, containing Al[sub 3]Ta precipitates approximately 50 [mu]m in diameter at applied potentials of 0.0, 1.0, 2.0, and 5.0 V SCE in a pH 7.2 borate buffer solution. At 0.0 V SCE the change in passive film thickness on the precipitatemore » was greater than that on the Al matrix. The changes in film thicknesses at 1.0 V SCE were approximately equal and at higher potentials (2.0 and 5.0 V SCE) the matrix film thickened more than the film on the precipitate. SEM observations demonstrate that the precipitate-matrix interface is highly susceptible to localized attack when the passive film on the Al[sub 3]Ta is thicker than on the matrix (at 0.0 V SCE). The authors propose that pit initiation occurs at both the interface of the Al[sub 3]Ta precipitation and in the dealloyed region around its periphery.« less
  • A silver/silver chloride microelectrode was developed as a liquid-phase ion gun for investigation of precursor processes of pitting corrosion. This electrode was set as a probe electrode of a scanning electrochemical microscope and used to induce a local breakdown of passive film on iron. A small amount of chloride ions generated by cathodic polarization of the silver/silver chloride microelectrode has succeeded in inducing the local breakdown of the passive film formed on iron in deaerated pH 6.5 borate solution. Moreover, the microelectrode could detect ferric ions dissolved from the film at the initial stage of the film breakdown.
  • The critical solution composition required for sustained growth of hemispherical single corrosion pits on pure aluminum in basic sodium chloride solution was studied. Single corrosion pits were initiated by using a laser initiation technique. Electrochemical current interruption experiments were used to probe the effects of bulk solution concentration and potential on pit stability. A mathematical model was used to analyze the results from one type of current interruption experiment that investigated the effect of pit size on pit stability. The mathematical model extended the results of previous work (Part 1, the previous article), which considered the profiles that develop duringmore » pit growth, to include transient behavior during the relaxation of the concentration profiles. The solution of the transient model was performed by first transforming the equations using the conformal mapping technique of Verbrugge et al. Numerical results were compared with experimental data and were interpreted on the basis of the hypothesis that a critical concentration of an ionic species is required in the pit for stability.« less
  • The halide island model for the initiation of pitting corrosion was tested for the occurrence of the electrochemical noise during the induction period before pits start. The halide island was modeled by a disk of metal halide of radius r and thickness d, formed on the surface of a passive film. A critical condition concerning the size of such islands for the stable formation and growth was determined with the use of irreversible thermodynamic stability criterion. From the stochastic analysis concerning the growth/diminishing processes of halide islands inside the metal oxide film, a distribution function was obtained for the numbermore » of halide islands which have radius r and thickness d. The survival probability of pit initiation and the noise level of the current were determined using this distribution function. Good correspondences with the reported experimental results were obtained, indicative of the applicability of the model to passive metals of thin oxide films.« less