Stress Corrosion Cracking of Zircaloy-2 in Neutral Aqueous Chloride Solutions at 25 C

1 April 1973

journal article
Published by Association for Materials Protection and Performance (AMPP) in Corrosion

Vol. 29 (4) , 157-168
https://doi.org/10.5006/0010-9312-29.4.157

Abstract

Studies have shown that stress corrosion cracking (SCC) of unnotched Zircaloy-2 specimens can be obtained in neutral aqueous chloride solutions provided the specimen is polarized anodically beyond the film breakdown potential. The value of this breakdown potential as a function of chloride concentration has been established for the batch of material used in this study, and is +100 mV (SCE) in 5% NaCl solution. It is possible to achieve this degree of anodic polarization of preoxidized specimens by galvanic coupling. The cracks are initiated by transgranular crystallographic pits, which initiate at points of oxide breakdown, and propagate by largely transgranular active path dissolution. From experiments in D₂O it was possible to show that no hydrogen uptake occurs during the pitting process, within the limits of detectability.

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