| Titre : | Atomic transport mechanisms in thin oxide films grown on zirconium by thermal oxidation, as-derived from 18O-tracer experiments (2012) |
| Auteurs : | G. Bakradze, Auteur ; L.P.H. Jeurgens, Auteur ; T. Acartürk, Auteur |
| Type de document : | Article : texte imprimé |
| Dans : | Acta materialia (Vol. 59 N° 20, Décembre 2011) |
| Article en page(s) : | pp. 7498–7507 |
| Note générale : | Métallurgie |
| Langues : | Anglais |
| Tags : | Oxidation Mechanism Nanocrystalline films Zirconium Time-of-flight secondary ion mass-spectrometry |
| Résumé : | Two-stage oxidation experiments using 16O and 18O isotopes were performed to reveal the governing atomic transport mechanism(s) in thin (thickness <10 nm) oxide films grown during the initial stages of dry thermal oxidation of pure Zr at 450 K. To this end, bare (i.e. without a native oxide) Zr(0 0 0 1) and Zr single-crystalline surfaces were prepared under ultra-high vacuum conditions by a cyclic treatment of alternating ion-sputtering and in vacuo annealing steps. Next, the bare Zr surfaces were oxidized at 450 K and at pO2 = 1 × 10−4 Pa, first in 16O2(g) and subsequently in 18O2(g). The 18O-tracer depth distributions in the oxide films were recorded by time-of-flight secondary ion mass spectrometry. It was concluded that the early stage of the oxidation process is governed by oxygen transport to the metal/oxide interface through the lattice and along the grain boundaries of the nanosized oxide grains whereas, on continuing oxidation, only oxygen lattice transport controls the oxidation process. An oxide-film growth mechanism is proposed. |
| ISSN : | 1359-6454 |
| En ligne : | http://www.sciencedirect.com/science/article/pii/S1359645411006124 |
