Characterizations of super hard Cu films containing insoluble W prepared by sputter deposition

The microstructure and properties of Cu films containing insoluble W in as- deposited and as-annealed conditions have been studied. The Cu-W films cons ist of non-equilibrium supersaturated solid solutions of W in Cu with nanoc rystalline microstructures. In this study, Cu-W films have been prepared us ing an RF magnetron sputter deposition technique. As the tungsten content i ncreases, the film crystallites decrease in size, suggesting that the addit ion of tungsten in the Cu-W films plays an important role in the inhibition of grain growth/coalescence during deposition. Decreasing trend for the de position rate with the tungsten content in the film is obtained. The film h ardness and wear resistance properties correlate well with the microstructu re and governed by the impurity effect of tungsten. Hardness and wear resis tance results indicate that the strengthening of films is mainly due to the fine structure and presence of tungsten. Compared to other insoluble eleme nts such as Mo, Ta and C, W has resulted in a better wear resistance proper ty when the maximum soluble tungsten content is 11.1 at.% in films. (C) 200 1 Elsevier Science B.V. All rights reserved.