paper

Anomalous Diffusion along Metal/Ceramic Interfaces

arXiv:1807.04708 · doi:10.1038/s41467-018-07724-7

Abstract

Hole formation in a polycrystalline Ni film on an $I^\pm$ -Al $_{2}$ O $_{3}$ substrate coupled with a continuum diffusion analysis demonstrates that Ni diffusion along the Ni/ $I^\pm$ -Al $_{2}$ O $_{3}$ interface is surprisingly fast. Ab initio calculations demonstrate that both Ni vacancy formation and migration energies at the coherent Ni/ $I^\pm$ -Al $_{2}$ O $_{3}$ interface are much smaller than in bulk Ni, suggesting that the activation energy for diffusion along coherent Ni/ $I^\pm$ -Al $_{2}$ O $_{3}$ interfaces is comparable to that along (incoherent/high angle) grain boundaries. Based on these results, we develop a simple model for diffusion along metal/ceramic interfaces, apply to a wide range of metal/ceramic systems and validate it with several ab initio calculations. These results suggest that fast metal diffusion along metal/ceramic interfaces should be common, but is not universal.