Nitrogen effects on structure, mechanical and thermal fracture properties of CrN films.

In this research, reactive pulsed dc magnetron sputtering with different Ar/N 2 gas flow ratios was used to deposit CrN films with three growth structures on Si substrates. The phase structure, morphology, mechanical properties, thermal fracture properties, and oxidation behavior of films were studied. The surface roughness, residual stress, preferred orientation, and hardness were affected by the gas flow ratio. The film with (200) preferred orientation and zone II structure performed the best. The surface roughness increased to 6 nm with time when the films fractured at 500 °C. The Cr interlayer oxidation caused by oxygen diffusion through grain boundaries and fracture accelerated degradation of CrN films at higher temperatures. A dense microstructure is favorable for preventing coating oxidation. • The sputtering gas ratio could affect surface morphology, roughness, and deposition rate •The residual stress changed from compressive to tensile with film thickness, a film with (200) preferred orientation and zone II structure performed the best •The Cr interlayer oxidation accelerated the degradation of CrN films, a dense microstructure is favorable for preventing coating oxidation [ABSTRACT FROM AUTHOR]