Mechanical, Tribological and Corrosion Behaviour of the Magnetron-Sputtered VN Coatings, Deposited at Different Substrate Temperatures

Vanadium nitride (VN) ceramic layers were deposited on 304 L stainless steel speci-mens by Direct Current (DC) magnetron sputtering in an Ar/N2 gas mixture at sub-strate temperatures of 250 oC, 300 oC and 350 oC. The obtained films were evaluated by X-Ray Diffraction (XRD), X-ray photoelectron spectrоscopy (XPS) and Atomic force microscopy (AFM). X-Ray diffraction patterns demonstrated the presence of (111), (200), (220) and (300) crystallographic orientations, corresponding to the VN and V2N phases, respectively. It was found out that the surface roughness (10 nm) diminishes as the temperature raises up to 350 oC. The highest hardness (10.6 GPa) was achieved in the layer, produced at 300 oC. The low values of the plastic and elastic deformation as well low friction coefficient (0.38) lead to enhancement of coatings wear resistance. The films thickness is increased with the raising of the temperature due to a presence of nucleation centres in the films. The highest thickness (500 nm) is achieved in the layer, deposited at 350 oC. The electrochemical tests exhibited a reliable protection against corrosion in strongly aggressive electrolytes. It was proved that the tempera-ture variation effects significantly the ceramic coatings structural, morphological, tribological and corrosion properties.