Growth Morphology, Adhesion and Mechanical Properties of Room-Temperature Pulsed Laser Deposited Cr-CrN Multilayer Coatings

Abstract The mechanical behaviour of multilayer coatings is strongly influenced by all growth phenomena occurring at the interfaces formed between the different layers. In the current work, this is shown for Cr-CrN multilayer coatings deposited at room temperature by the pulsed laser deposition technique on austenite steel substrates. Transmission electron microscopy investigations of the CrN-Cr interfaces revealed after a nucleation of about 10–12 nm large Cr grains on the underlain CrN layer and a sudden decrease in the grain size to 3–10 nm for the next 30–40 nm growth. When compared to pure Cr and CrN coatings, this seems to stay in close correlation to improved tribological and mechanical properties for the multilayer films with ∼80 to 180 nm thick alternating Cr and CrN layers, and a significant decrease in hardness and increase in the closely connected wear rate for thinner coatings.