Grain boundary character dependence of oxygen grain boundary diffusion in α-Al2O3 bicrystals

We measured oxygen diffusion coefficients (Dgb) along five grain boundaries (GBs) in alumina bicrystals by tracing 18O by secondary ion mass spectrometry. Although all boundaries are classified as coincident site lattice boundaries with relatively ordered structures, Dgb varied up to 103 times among them. On the other hand, the boundaries with identical boundary planes had relatively similar diffusivities as well as similar structures, regardless of Σ values. These results suggest that Dgb are related to GB atomic structures and hence the GB character, especially GB planes.