Surface Morphology and Mechanical Properties of Vacuum-Arc Evaporated CrN and TiN Coatings on Cutting Tool

Abstract

The studies are aimed at increasing the wear resistance of packaging knives made of Cr12 stainless steel used in wrapping machines of MC1DT-T type by thin TiN and CrN coatings obtained by vacuum-arc evaporation with RF discharge. The results of the complex analysis of degradation processes occurred in metal knife structure during operation were used to determine optimal parameters for further tool hardening technology. The surface morphology and elemental composition of initial and coated sample were studied by SEM with EDX. The quantity, size, volume of the carbide phase, as well as its distribution on the tool surface were calculated and analyzed using Thixomet Pro program. The maximum nanohardness of CrN coating comprised 31.46 GPa, whereas for TiN it was 34.31 GPa. It was revealed, that PVD coatings allowed to stabilize the working surface layer under deformation, and to hamper the development of diffusion processes. It was established, that the service-life of cutting knives is increased by 2–3 times.