Modulation effect on mechanical properties of nanolayered MoN/MoSiN coatings

The combination of molybdenum nitride, MoN, and molybdenum silicon nitride, MoSiN, to be a naolayered MoN/MoSiN film was developed by the reactive radio frequency, r.f., magnetron sputtering system. The MoN and MoSiN building layers were designed and fabricated with a crystalline and an amorphous/nanocrystalline feature, respectively. The effect of thickness modulation of the c-MoN and a-MoSiN layers on microstructure and mechanical properties of the MoN/MoSiN coatings were investigated. With a fixed 50.0 nm crystallines MoN building layer, the amorphous/nanocrystalline MoSiN building layer with a designed thickness of 25.0 nm would suppress the continuous growth of crystalline phases. For mechanical characterization, the change in modulation did not lead to significant influence on hardness and Young's modulus. When a large thickness ratio of c-MoN/a-MoSiN was applied, phenomenal increase in scratch and wear resistance was observed due to higher volumetric ratio of hard crystalline MoN layer and discontinuity of crystalline phase growth through building layers in the nanolayered MoN/MoSiN coatings.