(Cr1-x,Alx)N a review about a multi-purpose coating system

Nitride based coatings claimed a big market share for PVD-coatings. Especially in the field for high temperature die casting and cutting operations chromium based coatings are well used. These coatings are also used in low temperature processes for the coating of machine parts. In the beginning of the nineties first examinations are done on the ternary system Chromium-Aluminium-Nitride. This system shows an excellent corrosion behaviour against many different liquids, but gains also a high hardness for a good wear behaviour. By changing the AlN to CrN content and the coating design CrAlN opens up a wide range for different coating applications. A major step for machine parts was the reducing of coating process temperature beneath 200 degrees C. This was only possible by using pulsed power supplies. CrAlN shows a very good performance on the fast growing market of coated machine parts e.g. on spindle bearings.