Effect of Deposition Conditions on Microstructure and Composition of Nitride Monolayer and Carbide-Nitride Multilayer Coatings Based on W and Nb

This study investigates the structural and compositional evolution of monolayer WNbN and multilayer WNbN/WNbC coatings deposited by the cathodic arc evaporation. The effects of substrate bias voltage (–50 V to –200 V) and cathode arc current (130 – 150 A for W, 110 – 120 A for Nb) were systematically studied to tailor coating morphology, phase formation, and elemental distribution. Cross-sectional microstructural analysis revealed pseudo-multilayer structures within monolayers due to substrate rotation and limited interdiffusion. Increasing bias voltage promoted densification, grain refinement, and improved adhesion, but also enhanced the re-sputtering of nitrogen, affecting stoichiometry and deposition rates. Multilayer coatings showed well-defined alternations between nitride and carbide layers, with morphology and crystallinity strongly influenced by ion energy and metal ion flux. The structural analysis confirmed the dominance of cubic solid solutions based on WNbN and WNbC, with minor hexagonal W2N and Nb2N detected. Grain sizes ranged from 6 to 15 nm, depending on deposition parameters. Optimal structure was achieved at moderate bias (–120 V) and high W arc current, yielding uniform layers, balanced composition, and enhanced crystallinity. The results demonstrate how controlled process parameters enable the design of high-performance nanocomposite coatings with tunable microstructure and phase composition, suitable for protective applications.