Effect of silver vanadate on the lubricating properties of NiCrAlY laser cladding coating at elevated temperatures

Self-lubricating coating NiCrAlY/Cr3C2 (NiCr)/V2O5/Ag2O was prepared by laser cladding. Two different kinds of contrast samples were prepared in order to verify the excellent tribological properties of the composite coating. The composition and microstructure of the composite coating were characterized by X-ray diffractometry, scanning electron microscopy with energy spectrum analyzer (SEM-EDS). The tribological behavior of the coating from 25 °C to 800 °C was evaluated by a ball-on-disk tribometer and dual-mode 3D surface profiler, the corresponding wear mechanism of the composite coating was investigated by Raman spectroscopy. It has been found that the composite coating shows better tribological properties than the compared coatings when the temperature higher than 400 °C, the friction coefficient of composite coating was 0.143 and the wear rate was 2.86 × 10− 5 mm3/Nm at 800 °C. All these can be attributed to formation of the self-lubricant Ag3VO4 and AgVO3 with lamella structure on the worn surface. The wear mechanism of the composite coating is dominated by plastic deformation, delamination and adhesive wear at elevated temperature.