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Aakash Kumar1 Hagit Barda2 Michael W. Finnis3 4 Vincenzo Lordi5 Eugen Rabkin2 David Srolovitz1 6

1, University of Pennsylvania, Philadelphia, Pennsylvania, United States
2, Technion-Israel Institute of Technology, Haifa, , Israel
3, Imperial College London, London, , United Kingdom
4, Imperial College London, London, , United Kingdom
5, Lawrence Livermore National Laboratory, Livermore, California, United States
6, University of Pennsylvania, Philadelphia, Pennsylvania, United States

Metal-ceramic Interfaces are common to a wide range of technological applications, including Li-ion batteries, superalloy coatings, gate-oxides in microelectronics, etc. Transport of atoms along metal-ceramic interfaces critically affects the integrity and performance in all of these applications. While grain boundaries, dislocations, and surfaces are well-studied high-diffusivity paths, little is known about diffusion along metal-ceramic interfaces. We present the results of an extensive series of first-principles calculations of point defect formation and migration energies at/near Ni/α-Al2O3 interfaces. The dominant point defect is shown to be Ni vacancies under most experimental conditions. The Ni vacancy formation energy is nearly a factor of two smaller than that in the bulk metal. This leads to fast vacancy diffusion along the Ni/α-Al2O3 interface. We generalize this result to a wide range of other metal-ceramic interfaces using data readily available for many metal-ceramic systems and predict which should lead to high-diffusivity interface paths. We then validate these predictions by performing additional first-principles calculations on the Cu/α-Al2O3 system. Work partly performed under the auspices of US DOE by LLNL under Contract DE-AC52-07NA27344.

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