Influence of N2 gas pressure and negative bias voltage on the microstructure and properties of Cr–Si–N films by a hybrid coating system

Cr–Si–N films were deposited using a hybrid coating system combining arc ion plating and magnetron sputtering. The authors investigated the influence of N2 flux rate and negative bias voltage on the microstructure and properties of Cr–Si–N films, e.g., chemical composition, film morphology, phase structure, residual stress, and microhardness. The results showed that all the Cr–Si–N films were close to stoichiometry. The N2 flux rate had no important influence on the microstructure and properties of the Cr–Si–N films. Applying a negative bias voltage resulted in significant decrease in macroparticle densities and smoother film surface. Also the film microstructure transformed from apparent columnar to nanocomposite microstructure. The maximum microhardness obtained ranged from 45to50GPa at a bias voltage ranging from −50to−100V. The microhardness enhancement could be ascribed to the mixed effect of grain size diminishment and residual compressive stress.