Tribological properties of CrNx coatings

Purpose: The purpose of this work is the characterization of the tribological properties thin Cr-N coatings, both monolayer Cr2N, CrN coatings and multilayer Cr/CrN, Cr2N/CrN coatings, deposited by cathodic arc physical vapour deposition (CAPVD). Design/methodology/approach: The deposition parameters of Cr2N and CrN were determined. Structure of the coatings were investigated using the scanning electron microscopy (SEM). The XRD examination was carried out to specify the phase structure, EDS to define the chemical composition of the coatings. The investigation includes also microhardness, roughness tests, adhesion, friction coefficient and wear rate. Findings: Basing on the scratch test it was shown that the influence of the architecture on the coating’ adhesion is dominant. It was found that the all tested coatings show high critical load Lc2 >70 N. The multilayer coatings show higher critical load when compared to monolayer coatings. Research limitations/implications: The main limitation of this work is linked to the deposition technique itself.It is difficult to avoid surface defects and pinholes that strongly influence the tribological results. Practical implications: Chromium based coatings present good mechanical properties which allow them to be used in several applications; from decorative to protective coatings. Originality/value: The comparison of adhesion and wear resistance of mono- and multilayer coatings based on chromium. The deposition technology enable to obtain the coatings with high adhesion to the substrate. This may be important to advanced coatings industry.