Synthesis and characterization of low-friction W-V-N alloy coatings using reactive magnetron sputtering technique for tribological applications

In recent years, self-lubricating hard coatings have garnered significant interest across various industries such as cutting tools, molds, and manufacturing because of their ability to reduce friction and wear at high temperatures in dry-cutting applications. The present study focuses on synthesis of tungsten-vanadium-nitride (W-V-N) coatings using the reactive magnetron cosputtering technique in an Ar + N2 plasma gas environment. The coating microstructure, surface morphology, wetting behavior, and mechanical properties were characterized by grazing incidence x-ray diffraction, field-emission scanning electron microscopy, atomic force microscopy, energy-dispersive spectroscopy, and nanoindentation. Wear resistance properties of the prepared W-V-N alloy coatings were investigated using a ball-on-disk tribometer at two different temperatures. The findings indicate that all W-V-N coatings, regardless of the vanadium content, exhibit a face-centered cubic structure and form a solid solution of W-V-N. Among the coatings studied, W0.68V0.32N exhibited the highest hardness (14.25 GPa) and Young's modulus (257.53 GPa), as well as an excellent wear resistance. Increasing the vanadium content in the W-V-N coating led to a notable reduction in both the specific wear rate and friction coefficient. Moreover, this reduction was more pronounced with an increase in temperature during the wear test. Improvement in the wear properties can be attributed to the formation of Magnéli phases of vanadium oxides on the surface of the coatings. The ability of the W-V-N coating to reduce friction and wear, combined with its improved mechanical properties, makes it a promising candidate for solid lubricating coatings in tribological applications.