First principles study of oxygen diffusion in a α-alumina twin grain boundary

Abstract

We have investigated atomistic scale behaviour of oxygen diffusion along the twin grain boundary in α-Al₂O₃ (alumina) using molecular dynamics simulation and first principles total energy calculations. Based on the GB structure model which is verified by atomic-scale STEM observations on the bicrystal sample, quantitative evaluation of migration energies for dominant migration paths were performed by atomistic calculations. The preset calculation results confirmed fast oxygen diffusion behaviour along the GB. Our analysis shows that the dominant migration path or difference in the migration energies can be well correlated with the geometry of local atomic coordination around the migrating oxygen; lower migration energies are generally expected for paths with less change in coordination environment on migration. This trend holds both among gain boundary paths and bulk paths in α-alumina examined in the present study.

Keywords:

• alumina (α-Al₂O₃)
• grain boundary diffusion
• first principles calculation
• MD simulation
• bicrystal

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Grant-in-Aids for Scientific Research on Innovative Areas [grant number 25106003]; Young Scientists (B) [grant number 24760533]; Elements Strategy Initiative for Structural Materials (ESISM) from The Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.