How the crystallography and nanoscale chemistry of the metal/oxide interface develops during the aqueous oxidation of zirconium cladding alloys

N Ni, D Hudson, J Wei, P Wang, S Lozano-Perez, G D W Smith, J M Sykes, S S Yardley, K L Moore, S Lyon, R Cottis, M Preuss, C R M Grovenor

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Aqueous corrosion and hydrogenation have become major limiting factors to the use of zirconium alloys as fuel cladding and assembly components in water-cooled nuclear reactors. The metal-oxide interface has been a particular focus of previous research, but there is still no clear understanding of what is present at the interface at different stages of the complex oxidation process. We report here a systematic investigation using state-of-the-art instrumentation on the interfaces in several zirconium alloys corroded for different times. We have shown that thin intermediate oxide layers with compositions close to ZrO can be observed in almost all the pre-transition samples studied, and that this layer thickens during the pre-transition stage. Just before the kinetic transition, a large variation in the suboxide width was detected, suggesting that the kinetic transition is an extremely local process. After transition the suboxide was generally absent. In the suboxide locations different structures, including an unidentified phase, were found. The oxygen-saturated (∼30 at.% O) metal regions found beneath the oxide are thickest in the (late) pre-transition samples and significantly thinner in the post-transition samples. We suggest that the suboxide cannot by itself act as a protective layer and conclude that it is the development of interlinked porosity down to the metal-oxide interface that is the reason for the transition in oxidation kinetics. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
    Original languageEnglish
    Pages (from-to)7132-7149
    Number of pages18
    JournalActa Materialia
    Volume60
    Issue number20
    DOIs
    Publication statusPublished - 2012

    Keywords

    • Atom probe tomography (APT)
    • Corrosion mechanisms
    • Metal-scale interface
    • Transmission electron microscopy (TEM)
    • Zirconium alloys
    • Aqueous corrosion
    • Aqueous oxidation
    • Assembly component
    • Atom-probe tomography
    • Cladding alloys
    • Different structure
    • Fuel cladding
    • Kinetic transition
    • Metal oxide interface
    • Nano scale
    • Oxidation kinetics
    • Oxidation process
    • Oxide layer
    • Protective layers
    • Systematic investigations
    • Transmission electron microscopy tem
    • Cerium alloys
    • Corrosion
    • Crystallography
    • Kinetics
    • Nuclear reactors
    • Ternary alloys
    • Transmission electron microscopy
    • Zirconium

    Fingerprint

    Dive into the research topics of 'How the crystallography and nanoscale chemistry of the metal/oxide interface develops during the aqueous oxidation of zirconium cladding alloys'. Together they form a unique fingerprint.

    Cite this