Characterization of W-Ge-N coatings deposited by sputtering

The modified surfaces were characterised in the as-deposited state. It was found that the highest hardness (43 GPa) was obtained for the W-N film with the highest nitrogen percentage (60 at.%) which presented a mixture of cubic β-W2N and hexagonal δ-WN phases. The presence of Ge induced a decrease in the hardness, independently of the nitrogen content of the films. Further, the hardness could also be correlated with the residual stress of the coatings, regardless of their chemical composition, showing different behaviours according to their crystalline or amorphous nature.