Amorphous Cr-Zr-Nb and substoichiometric Cr-Zr-Nb-N films produced by HiPIMS: Microstructure and tribo-mechanical properties

Multicomponent thin films are increasingly used for protective applications against wear and corrosion. Introducing an optimized thin film system is crucial for anti-friction and anti-wear performance in mechanical applications. This paper investigates the effects of total pressure and nitrogen partial pressure on the microstructure and tribo-mechanical properties of Cr-Zr-Nb(N) films deposited via high-power impulse magnetron sputtering (HiPIMS). These parameters influence crystallinity (as determined by XRD, whether the coating is amorphous or crystallized in the fcc structure) and morphology (as determined by SEM, whether the coating exhibits a columnar or a dense-featureless structure). With these microstructural variations, the mechanical and tribological properties vary significantly. Hardness ranges from 12.5 GPa for the metallic film to 27.5 GPa for the low-nitrogen film and the wear rate ranges from 1×10⁻⁵ mm³/N·m for the metallic film to 3×10⁻⁷ mm³/N·m for the low-nitrogen film. A comparison of H, H/E, H³/E², 1/HE², and brittleness index data from selected samples with previously reported values demonstrates the impressive achievement of a system that is simultaneously hard and tough, owing to the combined use of a specific elemental composition and the HiPIMS method.