Structural, mechanical and tribological investigations of sputter deposited CrN–WS2 nanocomposite solid lubricant coatings

Nanocomposite coatings of CrN–WS2 were prepared at different Cr contents (approximately 8–39 at%) using an unbalanced magnetron sputtering system. Structural changes in CrN–WS2 coatings with variation in Cr content were studied using X-ray diffraction. CrN–WS2 coatings displayed a dense, compact microstructure with reduced columnar growth in the field emission scanning electron microscopy data. Nanoindentation and nanoscratch data showed that CrN–WS2 coatings exhibited improved mechanical and adhesive properties, respectively. Micro-tribometer tests at a load of 2 N indicated that CrN–WS2 coatings prepared at 31 at% Cr exhibited a stable friction coefficient of 0.20–0.24 even after 8 h.

► CrN–WS2 nanocomposite coatings were prepared by magnetron sputtering. ► A maximum hardness of 24 GPa and elastic modulus of 250 GPa were obtained. ► CrN–WS2 coatings exhibited Lc1 of 234 mN compared to 50 mN for WS2 coating. ► At a load of 2 N, CrN–WS2 coatings displayed a friction coefficient of 0.20–0.24.