Arc-deposited Ai—Cr—O coatings having enchanced coating properties
The present invention relates to a method for coating AI-Cr-0 coatings with the help of a PVD-coating process. The PVD-coating process is performed with the help of Al and Cr comprising targets which are doped with Si. The doping of Si prevents the forming of oxide islands on the target during the reactive coating process.
1. Method for producing PVD-oxide-coatings with at least one layer consisting essentially of Al, Cr, Si and O, the method comprising at least the following steps:
a) providing a PVD-coating chamber,
b) loading in the PVD-coating chamber substrates having at least one surface to be coated, and
c) performing a reactive PVD coating process using a process gas containing a reactive gas that reacts with metal ions produced from one or more targets for depositing the at least one layer consisting essentially of Al, Cr, Si and O on the substrate surface,
characterized in that, the one or more targets used for performing the reactive PVD coating process in step c) have an element composition in atomic percent given by the formula: Al 1−x−y Cr x Si y with 0.05≦y≦0.10 and 0.20≦x≦0.25 and the reactive gas is oxygen thereby producing a coating with the at least one layer consisting essentially of Al, Cr, Si and O, wherein, if oxygen is not taken into account, in the at least one layer the silicon concentration is less than the silicon concentration in the one or more targets, and
the PVD coating process is an arc evaporation process.
2. Method according to claim 1 characterized in that the process gas comprises essentially only oxygen.
3. Method according to claim 1 characterized in that y=0.05 and x=0.25.
4. Method according to claim 1 characterized in that wherein, if oxygen is not taken into account, in the at least one layer the silicon concentration is equal or less than half of the silicon concentration in the one or more targets.
5. Method according to claim 1 , wherein the coating forms an oxidation barrier.
6. Method according to claim 1 , wherein the coating forms a chemical barrier.
7. Method according to claim 1 , wherein the coating is used as a solid lubricant for tribological applications performed at temperatures higher than 200° C.