Influence of Mo contents on optimizing the microstructure and tribological properties of Cr-Mo-N films

Abstract The Cr-Mo-N films of different Mo contents are developed by the RF (Radio Frequency) magnetron sputtering. The XRD (X-ray Diffraction), SEM (Scanning Electron Microscope), EDS (Energy Dispersive Spectroscopy), nano-indenter and tribo-tester will be used to analyze the composition, phase structure, mechanical and tribological properties of films. The results reveal that the Cr-Mo-N film adopts a face-centered cubic structure, primarily oriented along the (111) plane. When the Mo content falls below 17.72%, increasing the Mo concentration leads to a slight increase in film microhardness, accompanied by a significant decrease in the average friction coefficient. On the contrary, exceeding a Mo content of 22.76% triggers structural changes within the film. These alterations are reinforced by solid solution and fine grain strengthening, further compounded by the presence of Mo2N. Consequently, film microhardness undergoes a considerable increase, while the average friction coefficient remains relatively stable irrespective of Mo content. This underscores the consistent low friction coefficient characteristic exhibited by Mo2N films.