(Tialv)N(1-X)Thin Films Deposited by Reactive Sputtering - Chemical-Composition

The microstructure and chemical composition of sputtered thin films are strongly correlated with the deposition conditions. In the present work, we report the investigation of the film composition by electron probe microanalysis and photoemission experiments. These analyses demonstrate the progressive nitridation of the films, which change from tetragonal-like Ti2N to f.c.c.-like TiN phases, by increasing the nitrogen partial pressure in the reactive plasma. The electron spectroscopy for chemical analysis measurements also show that the surface of the sputtered films consists of two layers: a bulk material and an altered transition layer with TiO(x), Al2O3 and VO(x) oxides as the top layer. The bonding in the nitride transition layer is weaker than that in the bulk material, because of surface oxidation (oxynitrides). Our results demonstrate that hard coatings with microhardness values higher than 5600 kg mm-2 Hv0.5 can be deposited from Ti-6wt.% Al-4wt.%V targets.