Structure and Mechanical Properties of CrN Thick Films Deposited by High-Rate Medium-Frequency Magnetron Sputtering

A home-made electron source assisted medium-frequency (MF) magnetron sputtering system was used to deposit thick CrN films on silicon and tungsten carbide substrates at various nitrogen flow rates with a fixed total pressure (0.3 Pa) and MF power (11.2 kW). Result from scanning electron microscopy showed that the deposited CrN films have clear columnar structure, and X-ray diffraction revealed a preferred orientation of CrN (200) for samples prepared at a rate of N2/(N2+Ar) below 60%, whereas those prepared at higher N2/(N2+Ar) rate are dominated by Cr2N. Deposition rates up to 12.5 μm/h were achieved and the hardness of the CrN coatings were in a range of 11 GPa to 18 GPa.