Microstructural characterisation of Cr-Al-N nanocomposites deposited by cathodic arc evaporation

摘要

The Cr-Al-N nanocomposites with a variable [Cr]/([Cr]+[A1]) ratio were deposited by cathodic arc evaporation. The investigations using XRD and TEM were done to analyse the microstructure of the coatings. The XRD phase analysis showed that Cr-rich coatings up to [Cr]/([Cr]+[Al]) = 0.54 consisted of a single fcc phase. With increasing Al-content, wurtz-itic AIN developed as a second phase. The Cr-Al-N nanocomposites are composed of nano-sized clusters that consist of partially coherent nanocrystallites. This microstructural model was obtained from the combination of the XRD line profile analysis and TEM. The mutual misorientation of the fcc nanocrystallites within the clusters was between 0.5° and approx. 1° as calculated from the onset of their partial coherence. Detailed TEM investigations per-formed on Cr-rich coatings revealed that in the single phase coatings the nano-sized clusters are separated by dislocation walls. The dislocations building the walls could be identified as screw dislocations.