Oerlikon Surface Solutions Ag, Pfaffikon

Robert Raab

Mirjam Arndt

Paul Heinz Mayrhofer

Christian Martin Koller

Jürgen Ramm

Juergen Ramm

A method for producing an Al—Cr—O-based coating on a workpiece surface, including: a) placing a workpiece in an interior of a vacuum chamber, and b) depositing a film comprising aluminum and chromium on the workpiece surface to be coated, wherein a ratio of aluminum to chromium in the film in atomic percentage has a first value corresponding to Al/Cr≤2.3, and c) forming volatile compounds of Cr—O, thereby causing at least part of the chromium contained in the film to leave the film in a form of Cr—O volatile compounds, and d) executing step c) during a period of time, within which the chromium content in the film is reduced until attaining a second value of the ratio of aluminum to chromium in the film in atomic percentage corresponding to Al/Cr≥3.5, thereby the film is transformed into a film containing a reduced content of chromium.

Al—Cr—O-based coatings with higher thermal stability and producing method thereof

The present invention relates to a method for producing a multilayer film comprising aluminum, chromium, oxygen and nitrogen, in a vacuum coating chamber, the multilayer film comprising layers of type A and layers of type B deposited alternate one of each other, wherein during deposition of the multilayer film at least one target comprising aluminum and chromium is operated as cathode by means of a PVD technique and used in this manner as material source for supplying aluminum and chromium, and an oxygen gas flow and a nitrogen gas flow are introduced as reactive gases in the vacuum chamber for reacting with aluminum and chromium, thereby supplying oxygen and nitrogen for forming the multilayer film, characterized in that: &#x2014;The A layers are deposited as oxynitride layers of Al&#x2014;Cr&#x2014;O&#x2014;N by using nitrogen and oxygen as reactive gas at the same time, &#x2014;The B layers are deposited as nitride layers of Al&#x2014;Cr&#x2014;N by reducing the oxygen gas flow and by increasing the nitrogen gas flow in order to use only nitrogen as reactive gas for the formation of the Al&#x2014;Cr&#x2014;N layer, and wherein the relation between oxygen content and nitrogen content in the multilayer film correspond to a ratio in atomic percentage having a value between and including 1.8 and 4.

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Vienna, Austria

Robert Raab