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We investigated the effect of film thickness on the structure and properties of VeN coatings deposited by magnetron sputtering in an argon and nitrogen atmosphere. The nitrogen percentage was changed between 10 and 20%. Firstly, structural and morphological properties of VeN films were observed, analyzed and subsequently followed by a detailed investigation on the mechanical and tribological properties of these coatings. It has been shown that film structure, hardness and wear resistance significantly changed with varying the film thickness and the nitrogen percentage. In the case of films deposited under 10%N 2 , the presence of V 2 N phase was evident. With increasing nitrogen ratio in the deposition chamber from 10 to 20%, the structure was changed from (hc)V 2 N to multi phases of V 2 N and (fcc) VN (formation of different vanadium nitrides). The thick films containing more nitrogen were slightly dense compared to the thinner ones presenting rough surface and columnar morphology. Nanoindentation measurements showed that film mechanical behavior depends on its thickness, nitrogen percentage and microstructural features. The film hardness first increased with its thickness and then decreased. The highest hardness of 26.2 GPa was obtained for the film deposited under 20%N 2 , which is correlated with its dense structure and film stoichiometry. The film thickness has a significant effect on the tribological properties of VeN films. The minimum friction coefficient of 0.4 was found for the thickest film of 2500 nm. The wear rate gradually decreased with increasing the film thickness, due to the high hardness, presence of VN phase and the strong adhesion between film and substrate.

Chromium nitrides were deposited by RF reactive magnetron sputtering from a Cr target on high carbon steel substrates XC100 (1.17 wt% carbon) in a N 2 and Ar gas mixture. In order to investigate the formation of chromium nitrides, carbide and carbonitride compounds were subjected to vacuum annealing treatment for 1 h at various temperatures ranging from 700 to 1000°C. The samples were characterized by EDS, XPS, XRD, SEM, nanoindentation and tribometry. The results showed the emergence of Cr 2 N and CrN during the early stages of annealing and the appearance of chromium carbonitride phases only at 900°C. The (111) preferred orientation of the fcc CrN phase was changed to (002) at 900°C in parallel with the appearance of chromium carbides. Nanoindentation tests revealed a gradual increase of the Young's modulus from 198 to 264 GPa when increasing the annealing temperature, while the hardness showed a maximum value (H = 22.4 GPa) at 900°C. The low friction coefficient of the CreCeN coating against a 100Cr6 ball was approximately 0.42 at 900°C. The enhancement of mechanical and tribological properties was attributed to the stronger bonding CreC at the CrN/ XC100 interfaces as confirmed by XPS results.

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Magnetron sputtering is one of the most commonly used deposition techniques, which has received considerable attention in industrial applications. In particular, owing to its compatibility with conventional fabrication processes, it can produce and fabricate high-quality dense thin films of a wide range of materials. In the present study, nitrogen (N) was combined with pure vanadium in order to form binary nitride to improve its mechanical and tribological performance. To evaluate the influence of nitrogen on the structure of the as-deposited vanadium nitride (VN) coatings, the following techniques were used: XPS, XRD, SEM, AFM and optical profilometry. The residual stresses were determined by the curvature method using Stoney’s formula. The hardness and Young’s modulus were obtained by nanoindentation measurements. The friction behavior and wear characteristics of the films were evaluated by using a ball-on-disk tribometer. The obtained results showed that the N/V ratio increased with increasing the N2 flow rate while the deposition rate decreased. The preferred orientation was changed from (200) to (111) as the N2 flow rate increased with the presence of V–N and V–O binding energies as confirmed by XPS analysis. The nitrogen addition resulted in a columnar morphology and a fine structure with fine surface roughness. The VN thin film containing 49.5 at.% of nitrogen showed the best performance: highest mechanical properties (hardness = 25 GPa), lowest friction coefficient (μ = 0.37) and lowest wear rate (Ws = 2.72 × 10−5 mm3N−1 m−1). A good correlation between the film microstructure, crystallite size, residual stress and mechanical and tribological properties was observed.

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Ever since the discovery of black silicon, scientists have been trying to come up with novel methods of utilizing this material in a variety of different industries due to its low reflectivity and excellent electronic and optoelectronic properties.

Vanadium carbide coatings were deposited by R.F. reactive magnetron sputtering at different nitrogen partial pressures. The structures and the mechanical and tribological behaviour of these coatings were studied. By using a combined approach of EDS and WDS, it has been shown that increasing nitrogen concentration from 0 to 27 at.% led to decrease the carbon content from 48.50 to 30.50 at.%. All coatings exhibited a dominant fcc-VC structure with additional fractions of vanadium nitrides, as determined by XRD. Nanoindentation measurements showed that the highest hardness of 26.1 GPa was obtained for the coating with a (N + C) / (V) ratio equal to 1.44. The transition in brittleness-ductile failure mode was noticed with increasing nitrogen content. This adhesive feature can prevent phase separation and improves the wear resistance of the coatings. Moreover, the nitrogen partial pressure showed a significant influence on the friction coefficient because of film density and residual stress effects.