Dissolution and repassivation kinetics of Fe-Cr alloys in pit solutions. I. Effect of the surface salt layer

Journal Article · Mon Mar 01 04:00:00 EST 1993 · Journal of the Electrochemical Society; (United States)

DOI:https://doi.org/10.1149/1.2056137· OSTI ID:6449235

Steinsmo, U; Isaacs, H S ^[1]

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1. Brookhaven National Lab., Upton, NY (United States)

A study of the dissolution and repassivation of an Fe-17.4 a/o Cr alloy in a pencil-type artificial pit simulating one-dimensional diffusion, has been carried out in a chloride-containing bulk solution. The attainment of saturation of dissolution products within the artificial pit was characterized by the formation of a salt layer on the alloy surface. A transport model has been used to calculate the decrease in concentration at the metal interface for currents below that required to maintain the salt layer. The concentration at the metal interface was calculated from the balance of electrochemical dissolution and diffusion in the localized environment. The dissolution rate of the alloy showed a maximum at a particular concentration and, both this concentration, and the rate, increased with potential. Passivation took place below a critical concentration. The potential and critical current for passivation increased with potential. The dissolution kinetics were affected by a remnant film that was present on the metal surface after the salt layer had dissolved. Its effects during active anodic dissolution slowly disappeared with time.

• DOE Contract Number: AC02-76CH00016
• OSTI ID: 6449235
• Journal Information: Journal of the Electrochemical Society; (United States), Journal Name: Journal of the Electrochemical Society; (United States) Vol. 140:3; ISSN JESOAN; ISSN 0013-4651
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360105* -- Metals & Alloys-- Corrosion & Erosion
ALLOYS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHROMIUM ALLOYS
CORROSION
CRITICAL CURRENT
CURRENTS
DATA
DIFFUSION
DISSOLUTION
ELECTRIC CURRENTS
ELECTRIC POTENTIAL
EXPERIMENTAL DATA
INFORMATION
IRON ALLOYS
IRON BASE ALLOYS
KINETICS
MATHEMATICAL MODELS
NUMERICAL DATA
PASSIVATION
PITTING CORROSION
QUANTITY RATIO
REACTION KINETICS
SALTS
SURFACE PROPERTIES