Study of cathode current effect on the properties of CrAlSiN coatings prepared by LARC

The aim of this paper is to investigate effect of cathode current on the properties of a series of CrAlSiN nanocomposite monocoatings prepared by the lateral rotating cathodes arc technique using the PLATIT π80 + DLC coating device and were deposited onto high speed steel HSS 6-5-2-5. The influence of the cathode arc current as well as increasing in the Al and Si content were studied in order to determine the coating properties. A sudden change of preferred orientation from (111) → (002) was observed in the interval from 1.3 to 1.7 at. % of Si, and 13.0 to 15.0 at. % Al, respectively. This change of preferred orientation is due to the incorporation of Al and Si into coatings, which also leads to an increased volume of Si3N4 matrix. All as-deposited coatings exhibit continuous nanohardness increment from 30 ± 1.8 to 34.2 ± 1.5 GPa with increasing Al + Si due to strengthening the solid solution and precipitation of the Si3N4 silicon nitride from the saturated CrAlSiN lattice at ∼2.3 at. % of Si. Coatings deposited with cathode current ratio (CCR) ≥ 1.00 satisfy the H/E* ≥ 0.1 condition for simultaneously hard and tough coatings. The chemical composition, XRD structure, residual stresses, surface roughness and nanohardness were systematically characterised using a scanning electron microscope (SEM) fitted with Energy-dispersive X-ray analysis (EDX), X-ray diffraction (XRD), laser scanning confocal microscope (LSCM) and nanoindentation.