Effect of heat treatment on structure and properties of molybdenum nitride and molybdenum carbonitride films prepared by magnetron sputtering

Abstract The molybdenum nitride (MoN) film with multiphase structure (Mo 2 N, MoN and Mo) was successfully prepared using magnetron sputtering. The mechanical and tribological performances of the MoN film were both further improved by C-doping and heat treatment. The results show that compared to the MoN film, the MoCN film has smoother and denser microstructure, lower friction coefficient and wear rate, and an increased hardness of 28 GPa. The improved performance exhibited by the MoCN film is mainly attributed to the lubricating effect of forming amorphous carbon after doping with C element and high hardness of the sp 3 C C hybrid bond. However, different results exhibited on the MoN and MoCN films after heat treatment at 400 °C. Both the mechanical and tribological properties were improved in the MoN film but reduced in the MoCN film. This may be related to different crystallization of Mo and the change of amorphous carbon in the different film. This suggests that heat treatment is of great importance to the properties of MoN and MoCN films.