Structural and mechanical properties of Cr-Al-O-N thin films grown by cathodic arc deposition
2012 (English)In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 60, no 19, 6494-6507 p.Article in journal (Refereed) Published
Coatings of (CrxAl1-x)(delta)(O1-yNy)(xi) with 0.33 less than= x less than= 0.96, 0 less than= y less than= 1 and 0.63 less than= delta/xi less than= 1.30 were deposited using cathodic arc evaporation in N-2/O-2 reactive gas mixtures on 50 V negatively biased WC-10 wt.% Co substrates from different Cr and Al alloys with three different Cr/Al compositional ratios. For N-2 less than 63% of the total gas, ternary (Cr,Al)(2)O-3 films containing less than1 at.% of N forms; as determined by elastic recoil detection analysis. Increasing the N-2 fraction to 75% and above results in formation of quaternary oxynitride films. Phase analyses of the films by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy show the predominance of cubic Cr-Al-N and cubic-(Cr,Al)(2)O-3 solid solutions and secondary hexagonal alpha-(Cr,Al)(2)O-3 solid solution. High Cr and Al contents result in films with higher roughness, while high N and O contents result in smoother surfaces. Nanoindentation hardness measurements showed that Al-rich oxide or nitride films have hardness values of 24-28 GPa, whereas the oxynitride films have a hardness of similar to 30 GPa, regardless of the Cr and Al contents. Metal cutting performance tests showed that the good wear properties are mainly correlated to the oxygen-rich coatings, regardless of the cubic or corundum fractions.
Place, publisher, year, edition, pages
Elsevier , 2012. Vol. 60, no 19, 6494-6507 p.
Physical vapor deposition; Solid solution; Face-centered cubic crystals; Alumina (alpha-Al2O3); Oxynitride
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-87218DOI: 10.1016/j.actamat.2012.08.010ISI: 000311188400006OAI: oai:DiVA.org:liu-87218DiVA: diva2:587406