Al-Cr-O-BASED COATINGS WITH HIGHER THERMAL STABILITY AND PRODUCING METHOD THEREOF

Abstract

The present invention relates to a method for producing an Al—Cr—O-based coatings comprising at least one Al—Cr—O-based or Al—O-based film on a workpiece surface, wherein the method comprises following steps: a) placing at least one workpiece having a surface to be coated in the interior of a vacuum chamber, and b) depositing a film A comprising aluminum and chromium on the workpiece surface to be coated, wherein the ratio of aluminum to chromium in the film in atomic percentage has a first value corresponding to Al/Cr≤2.3 and wherein the method further comprises following steps: c) forming volatile compounds of Cr—O, e.g. CrO3 and/or CrO2, thereby causing that at least part of the chromium contained in the film A left the film in form of Cr—O volatile compounds, d) executing the step c) during a period of time, within which the chromium content in the film A is reduced until attaining a second value of ratio of aluminum to chromium in the film in atomic percentage, thereby the film A being transformed in a film B containing a reduced content of chromium, which corresponds to an aluminum and chromium in a proportion corresponding to a ratio of Al/Cr≥3.5 or corresponding to a Cr content in atomic percentage of 0% or of approximately 0%.

Dependencies are inferred from the claim text.