Atomistic modeling of La3+ doping segregation effect on nanocrystalline yttria-stabilized zirconia

The effect of La3+ doping on the structure and ionic conductivity change in nanocrystalline yttria-stabilized zirconia (YSZ) was studied using a combination of Monte Carlo and molecular dynamics simulations. The simulation revealed the segregation of La3+ at eight tilt grain boundary (GB) structures...

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Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2018-01, Vol.20 (19), p.13215-13223
Main Authors: Zhang, Shenli, Sha, Haoyan, Castro, Ricardo H R, Faller, Roland
Format: Article
Language:English
Subjects:
Computer simulation
Diffusion
Diffusion coefficient
Doping
Grain boundaries
Ion currents
Molecular dynamics
Variations
Yttria-stabilized zirconia
Yttrium oxide
Zirconium dioxide
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Summary:The effect of La3+ doping on the structure and ionic conductivity change in nanocrystalline yttria-stabilized zirconia (YSZ) was studied using a combination of Monte Carlo and molecular dynamics simulations. The simulation revealed the segregation of La3+ at eight tilt grain boundary (GB) structures and predicted an average grain boundary (GB) energy decrease of 0.25 J m−2, which is close to the experimental values reported in the literature. Cation stabilization was found to be the main reason for the GB energy decrease, and energy fluctuations near the grain boundary are smoothed out with La3+ segregation. Both dynamic and energetic analysis on the Σ13(510)/[001] GB structure revealed La3+ doping hinders O2− diffusion in the GB region, where the diffusion coefficient monotonically decreases with increasing La3+ doping concentration. The effect was attributed to the increase in the site-dependent migration barriers for O2− hopping caused by segregated La3+, which also leads to anisotropic diffusion at the GB.
ISSN:1463-9076
1463-9084
DOI:10.1039/c8cp02010h