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Aluminium oxides are commonly used materials in both industry and scientific research. Their applications range from utilization as pure substrate in microelectronics and catalysis to wear-resistant coatings on cemented carbide cutting tools. Usually the aluminium oxide itself is grown on another substrate and exhibits some interface to other materials which are part of the specific application.
Hence, detailed knowledge about both, growth mechanisms as well as the micro-structure at the interfaces is of great technological and scientific relevance.
Here, we focus on growth of α-/κ-Al2O3 on titanium carbide/nitride, Ti(C,N), the proper substrates for CVD-fabricated wear-resistant coatings.
We use density functional theory to investigate the elementary steps of the growth process
at the initial stage: single atomic, full mono-layer, and thin-film adsorption.
For the Al2O3-films, and hence for the Al2O3/Ti(C,N)-interface, a large number of possible geometric structures exists. Calculating variations in total, surface, and interface energies of these films geometries on top of the Ti(C,N) surface, ultimately yields the micro-structure at the interface. Based on this knowledge we seek to model the subsequent growth of larger grains which together with the interface structure determines the overall mechanical properties.
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