Evolution of microstructure, anti-oxidation and tribological properties of CrAlN and VN based coatings in a wide temperature range

Abstract

To improve the wear resistance of Ni-based alloys at elevated temperatures, the CrAlN/VN multilayer coating was deposited by multi-arc ion plating. The wear tests at room temperature, 300, 500, and 700 °C were adopted to evaluate the tribology performance. The CrAlN/VN coating showed a dense cross-sectional structure, and the surface roughness of the multilayer coating was measured to be 85.3 nm, which is lower than that of the CrAlN coatings (101.7 nm). It indicates that the multilayer structure contributes to a smoother surface, which is beneficial for reducing friction and wear. The nanoindentation test showed that the hardness of the multilayer coating was 26.1 GPa, respectively, which was higher than those of the VN (18.8 GPa) and CrAlN (24.5 GPa) coatings. The CrAlN/VN multilayer coating displayed the lowest wear rate at 500 °C, which was about 3.2 × 10⁻⁶ mm³/N⋅m. The superior wear resistance of the multilayer coating was attributed to the formation of oxides at high temperatures. The wear rate of the coating will be significantly accelerated when the operating temperature exceeds the melting point of V₂O₅. This study provides a new strategy for the anti-wear protection of nickel-based alloys in a wide temperature range.