Mechanical properties and oxidation behavior of CrWSiN films

In this study, CrWSiN films were fabricated through direct current magnetron cosputtering, and the sputtering power applied to the target was selected as the process variable. In addition, the mechanical properties and oxidation resistance of CrWSiN films with Si contents of 9-10 and 15-18 at.% were evaluated and compared with those of CrSiN and WSiN films. Among the aforementioned films, crystalline Cr21W28Si9N42 films exhibited the highest hardness of 25.0 GPa and highest Young's modulus of 323 GPa because they contained W. The formation of oxide species in the CrWSiN films after annealing at 800 degrees C in ambient air was affected by the films' chemical compositions. W-enriched CrWSiN films exhibited low oxidation resistance because of the formation of WO3. However, the oxidation resistance of the Cr21W28Si9N42 films was higher than that of the W-enriched films. This improvement was achieved through the formation of a Cr2WO6 surface oxide layer above the WO3 oxide layer. Moreover, a Cr2O3 surface layer and an amorphous SiOx interface formed on the W-depleted films, which restricted their subsequent oxidation.