Structure, mechanical properties and oxidation behaviour of arc-evaporated NbAlN hard coatings

Autor: Robert Franz, C. Polzer, Christian Mitterer, M. Lechthaler
Rok vydání: 2010
Předmět:
Zdroj: Surface and Coatings Technology. 204:2447-2453
ISSN: 0257-8972
DOI: 10.1016/j.surfcoat.2010.01.023
Popis: Nb 1 − x Al x N hard coatings were synthesised by cathodic arc-evaporation in order to study the influence of the Al concentration on crystal structure, mechanical properties and oxidation resistance. Structural investigations by X-ray diffraction revealed a transition from the face-centered cubic structure of δ -NbN to the wurtzite structure of AlN at x = 0.45… 0.56 depending on the deposition parameters. The maximum values of the mechanical properties like hardness and residual stress obtained by nanoindentation and biaxial stress temperature measurements, respectively, were found for the coatings with cubic structure and generally decrease with increasing Al content. On the other hand, higher Al concentrations are beneficial in terms of oxidation resistance as shown by annealing experiments in ambient air. The onset temperature for oxidation rises from 600 to 700 °C for Nb 0.73 Al 0.27 N to above 800 °C for Nb 0.29 Al 0.71 N regardless of changes in the crystal structure.
Databáze: OpenAIRE