Influence of Bias Voltages on the Morphological, Mechanical, Tribological and Corrosion Properties of VN Coatings by Magnetron Sputtering

In our study, magnetron-sputtered vanadium nitride (VN) films were grown on 304 L stainless steel in an Ar/N2 atmosphere at a substrate bias voltage of 0 V, –50 V, –100 V,–150 V and – 200 V. The as-deposited VN coatings were characterized by X-ray dif-fraction (XRD), Fourier-transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The XRD and FTIR analysis exhibited a presence of VN crystalline phases. AFM and SEM exhibited that a decrease in the thickness and surface roughness with increasing the bias voltage to – 200 V. The VN coating, obtained at – 100 V, indicated a high hardness of 36.2 GPa. It was carried out that the friction coefficient is remarkably dependent by the film surface roughness. The lowest friction coefficients (0.42 and 0.44) for a loading force of 2 N and 5 N was evaluated for VN film, deposited at – 200 V which indicate a high degree of wear re-sistance. The electrochemical tests revealed that VN films, grown at a bias voltage of 0 V and – 200 V, have the most reliable protection against corrosion in aggressive elec-trolytes.