Effect of target material on deposition and properties of metal-containing DLC (Me-DLC) coatings

Metal containing diamond-like carbon (Me-DLC) coatings were prepared by magnetron sputter deposition using tungsten, tungsten carbide, niobium and titanium as target materials. An essential parameter for the process characterization is the target voltage. The substrate heating during the film growth depends on the target material. For the tungsten target, the contribution of energetic neutrals to the heat flux is quite high. From the viewpoint of resistance to abrasive wear, the best properties were found for W-DLC. The Nb-DLC coatings have an intermediate wear rate but offer the lowest friction coefficients and a high performance under adhesive wear loading. All Me-DLC coatings investigated in this study exhibit clearly higher wear rates than metal-free DLC films prepared by a radio frequency glow discharge technique. Metallic intermediate layers allow the preparation of coatings with a very good adhesion.