Anti-wear Cr-V-N coating via V solid solution: Microstructure, mechanical and tribological properties

Abstract V-containing solid solution was considered as a promising way to improve the mechanical and tribological properties of hard coatings due to the mechanism of solid solution as well as the induced V-based Magneli lubricant during friction process. In this work, Cr-V-N coatings with different V contents were prepared on polished cemented carbide and P-type Si (100) wafers by cathodic arc evaporation. The microstructure, mechanical and tribological properties of the coatings with varied V content were discussed. When the content ranged from 0.32 to 31.14 at.%, V entered into the lattice of CrN crystal in the form of solid solution without affecting the coating's phase composition. CrN phase with (111) orientation was formed for all Cr-V-N coatings, and the coating with 31.14 at.% V content showed the weakest crystallinity. The introduction of V still retained the composited coatings with high toughness and excellent adhesion strength of around 100 N on cemented carbide substrates. The maximum elastic modulus and hardness reached up to 438.5 ± 5.3 GPa and 20.0 ± 1.0 GPa, respectively, with V content at 16.55 at.%. Tribological tests at room temperature demonstrated that the friction coefficient of Cr-V-N coatings was relatively low, which was between 0.26 and 0.36. The wear rate was in the order of magnitude of 10−7 mm3N−1 m−1, and the lowest wear rate was 2.5 × 10−7 mm3N−1 m−1 with V content at 0.32 at.%. The friction coefficient and wear rate both increased with the increase of V content. The wear rate of the coatings with high V content (31.14 at.%) was almost four times higher than that of low V content (0.32 at.%) coatings.