Title: Tuning structure and mechanical properties of Ta-C coatings by N-alloying and vacancy population
Language: English
Authors: Glechner, Thomas 
Mayrhofer, P.H. 
Holec, D. 
Fritze, S. 
Lewin, E. 
Paneta, V. 
Primetzhofer, D. 
Kolozsvári, S. 
Riedl, H. 
Keywords: Ceramics; Computational methods; Design, synthesis and processing; Mechanical properties; Surfaces, interfaces and thin films
Issue Date: 2018
Journal: Scientific Reports
Abstract: 
Tailoring mechanical properties of transition metal carbides by substituting carbon with nitrogen atoms is a highly interesting approach, as thereby the bonding state changes towards a more metallic like character and thus ductility can be increased. Based on ab initio calculations we could prove experimentally, that up to a nitrogen content of about 68% on the non-metallic sublattice, Ta-C-N crystals prevail a face centered cubic structure for sputter deposited thin films. The cubic structure is partly stabilized by non-metallic as well as Ta vacancies – the latter are decisive for nitrogen rich compositions. With increasing nitrogen content, the originally super-hard fcc-TaC0.71 thin films soften from 40 GPa to 26 GPa for TaC0.33N0.67, accompanied by a decrease of the indentation modulus. With increasing nitrogen on the non-metallic sublattice (hence, decreasing C) the damage tolerance of Ta-C based coatings increases, when characterized after the Pugh and Pettifor criteria. Consequently, varying the non-metallic sublattice population allows for an effective tuning and designing of intrinsic coating properties.
DOI: 10.1038/s41598-018-35870-x
Library ID: AC15258050
URN: urn:nbn:at:at-ubtuw:3-4589
ISSN: 2045-2322
Organisation: E308 - Institut für Werkstoffwissenschaften und Werkstofftechnologie 
Publication Type: Article
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