Microstructure, mechanical and tribological properties of Mo-V-Cu-N coatings prepared by HIPIMS technique

A combination of high wear-resistance and low-friction is crucial for improving the wear performance of selflubricating coatings, which is generally determined by an excellent lubricating effect and mechanical strength. In this study, the Mo-V-Cu-N coatings were prepared by HIPIMS technique with a spliced target of Mo-V-Cu at various charge voltages. The results revealed that Mo-V-Cu-N coatings presented a solid solution phase of B1-MoVN with (200) preferred orientation, and the preferred orientation was enhanced at high charge voltages. Whereas the Cu atoms formed an amorphous phase in Mo-V-Cu-N coatings due to a low Cu content of 2.3-3.6 at.%. As the charge voltage increased to 750 V, more charged metallic ions were accelerated and bombarded substrate surface efficiently, forming smooth and dense Mo-V-Cu-N coatings with a high hardness of 31.0 GPa. All the coatings presented a low friction coefficient of 0.34-0.39 due to the formation of MoO2, VO2 and CuO mixed oxides, and the wear mechanism was dominated by abrasive and tribo-oxidation wear at room temperature.