Grain growth and phase stability of nanocrystalline cubic zirconia under ion irradiation

Journal Article · Wed Nov 10 04:00:00 EST 2010 · Physical Review. B, Condensed Matter, 82(18):184105:1-7

DOI:https://doi.org/10.1103/PhysRevB.82.184105· OSTI ID:994033

Zhang, Yanwen; Jiang, Weilin; Wang, Chong M; Namavar, Fereydoon; Edmondson, Philip D; Zhu, Zihua; Gao, Fei; Lian, Jie; Weber, William J

Grain growth, oxygen stoichiometry and phase stability of nanostructurally-stabilized zirconia (NSZ) in pure cubic phase are investigated under 2 MeV Au ion bombardment at 160 and 400 K to doses up to 35 displacements per atom (dpa). The NSZ films are produced by ion-beam-assisted deposition technique at room temperature with an average grain size of 7.7 nm. The grain size increases with dose, and follows a power law (n=6) to a saturation value of ~30 nm that decreases with temperature. Slower grain growth is observed under 400 K irradiations, as compared to 160 K irradiations, indicating that thermal grain growth is not activated and defect-stimulated grain growth is the dominating mechanism. While cubic phase is perfectly retained and no new phases are identified after the high-dose irradiations, reduction of oxygen in the irradiated NSZ films is detected. The ratio of O to Zr decreases from ~2.0 for the as-deposited films to ~1.65 after irradiation to ~35 dpa. Significant increase of oxygen vacancies in nanocrystalline zirconia suggests substantially enhanced oxygen diffusion under ion irradiation, a materials behavior far from equilibrium. The oxygen deficiency may be essential in stabilizing cubic phase to larger grain sizes.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 994033
• Report Number(s): PNNL-SA-75087; 34899; KC0201020
• Journal Information: Physical Review. B, Condensed Matter, 82(18):184105:1-7, Journal Name: Physical Review. B, Condensed Matter, 82(18):184105:1-7
• Country of Publication: United States
• Language: English

Related Subjects

Environmental Molecular Sciences Laboratory
nanocrystalline materials
vacancy
zirconia