MULTILAYER COATINGS - INFLUENCE OF FABRICATION PARAMETERS ON CONSTITUTION AND PROPERTIES

Multilayer TiC/TiB2 coatings were prepared by magnetron sputtering with various degrees of ion bombardment during deposition. In previous studies, it has been shown that a specific number of single layers, around 100 - 200 for a total layer thickness of 5 μm, produces optimum characteristics with regard to crack propagation resistance and wear behaviour, especially under interrupted cutting conditions. These are indications showing that cracks are deflected at the interface zones. These zones have an extension of about 2 - 3 nm after sputter deposition without "biasing" the substrate. Ion bombardment during deposition leads to similar interface zones, to modifications in the coating texture, and to the best coating properties being achieved at a larger number of single layers. Optimum properties and wear resistance were found for 500 single layers in a coating thickness of 5 μm. Constitution, properties and wear behaviour are discussed as a function of the fabrication parameters. © 1990.