Point-defect engineering of MoN/TaN superlattice films: A first-principles and experimental study

Varování

Publikace nespadá pod Ekonomicko-správní fakultu, ale pod Přírodovědeckou fakultu. Oficiální stránka publikace je na webu muni.cz.
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KOUTNÁ Nikola HAHN Rainer ZÁLEŠÁK Jakub FRIÁK Martin BARTOSIK Matthias KECKES Jozef ŠOB Mojmír MAYRHOFER Paul H. HOLEC David

Rok publikování 2020
Druh Článek v odborném periodiku
Časopis / Zdroj Materials and Design
Fakulta / Pracoviště MU

Přírodovědecká fakulta

Citace
www https://www.sciencedirect.com/science/article/pii/S0264127519306495?via%3Dihub
Doi http://dx.doi.org/10.1016/j.matdes.2019.108211
Klíčová slova Superlattices; Vacancies; Ab initio; Metastable phases; XRD; EDX
Popis Superlattice architecture represents an effective strategy to improve performance of hard protective coatings. Our model system, MoN/TaN, combines materials well-known for their high ductility as well as a strong driving force for vacancies. In this work, we reveal and interpret peculiar structure-stability-elasticity relations for MoN/TaN combining modelling and experimental approaches. Chemistry of the most stable structural variants depending on various deposition conditions is predicted by Density Functional Theory calculations using the concept of chemical potential. Importantly, no stability region exists for the defect-free superlattice. The X-ray Diffraction and Energy-dispersive X-ray Spectroscopy experiments show that MoN/TaN superlattices consist of distorted fcc building blocks and contain non-metallic vacancies in MoN layers, which perfectly agrees with our theoretical model for these particular deposition conditions. The vibrational spectra analysis together with the close overlap between the experimental indentation modulus and the calculated Young's modulus points towards MoN0.5/TaN as the most likely chemistry of our coatings.
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