Influence of Shielding Potential on the Formation Process of Nanostructured Nitride Coatings of the MoN/CrN System

Using the method of vacuum-arc deposition, multilayer MoN/CrN nitride coatings were synthesized under two different substrate bias potentials, specifically Ub  – 100 V and Ub  – 200 V. These coatings were deposited at a working nitrogen pressure of PN  0.53 Pa. The structural and mechanical properties of the obtained coatings were systematically studied, with a particular focus on microhardness and thermal stability. The investigation revealed that increasing the bias potential from – 100 V to – 200 V led to a significant enhancement in the hardness of the coatings. Specifically, the coatings deposited at Ub  – 200 V demonstrated a 23.5 % higher hardness compared to those produced at Ub  – 100 V, indicating improved densification and possibly finer microstructural features induced by the higher energy ion bombardment. The measured microhardness values (HV0.05) of the as-deposited coatings were 25.6 GPa for Ub  – 100 V and 28.8 GPa for Ub  – 200 V. These values confirm the beneficial effect of a higher negative substrate bias on the mechanical performance of the multilayer architecture. Furthermore, post-deposition annealing at T  700 °C was performed to assess the thermal stability and possible phase transformations. Interestingly, annealing did not result in an increase in hardness; on the contrary, a slight reduction in average microhardness was observed for the coating deposited at Ub  – 100 V, with the value decreasing to 24.3 GPa. However, for the coating obtained at Ub  – 200 V, annealing led to a slight increase in hardness, reaching 30.8 GPa, suggesting enhanced thermal stability and resistance to softening. These findings highlight the importance of deposition parameters in tailoring the performance of multilayer nitride coatings for high-temperature and wear-resistant applications.