Abstract
The atomic structure, energetics and chemical bonding state of pristine and Y doped Σ13, (10 4) grain boundaries in α-Al2O 3 were investigated by aberration-corrected Z-contrast scanning transmission electron microscopy combined with first-principles calculations. Combining observations from two orthogonal directions parallel to the grain boundary plane, we found that Y atoms segregate into specific atomic sites and form two-dimensionally ordered structure. We performed first-principles calculations to estimate stable atomic sites for Y segregation, and it was found that the calculation results are in good agreement with the experimental results. Local chemical bonding states at the core of the boundary were investigated by a first-principles orthogonalized linear combination of atomic orbitals (OLCAO) method, and Y atoms and neighboring O atoms were found to evince strong ionic character while O-Al back bonds evince strong covalent character.
Original language | English |
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Pages (from-to) | 1158-1171 |
Number of pages | 14 |
Journal | Philosophical Magazine |
Volume | 93 |
Issue number | 10-12 |
DOIs | |
Publication status | Published - 2013 Apr 1 |
Externally published | Yes |
Keywords
- HAADF STEM
- Y doping
- alumina
- chemical bonding character
- first-principles calculations
- grain boundary
- segregation
ASJC Scopus subject areas
- Condensed Matter Physics