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

Abstract

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.