Characterization of TiAlSiON coatings deposited by plasma enhanced magnetron sputtering: XRD, XPS, and DFT studies

•Hard coatings deposited on stainless steel•Plasma enhanced magnetron sputtering•Formation of TiAlSiON coatings•XPS and DFT characterization of hard coatings

The results of characterization of TiAlSiON hard coatings deposited on ferric-chromium AISI 430 stainless steel by plasma enhanced magnetron sputtering are presented. The coating with maximum hardness (of 43 GPa) was obtained at the following optimal values of elemental concentrations: Si ~ 5 at.%, Al ~ 15 at.%, and Ti ~ 27 at.%. The value of gaseous mixture (Ar–N2) pressure was of 0.13 Pa and the value of partial pressure of oxygen (O2) was 1.3 · 10− 3 Pa. The X-ray diffraction (XRD) measurements showed the presence of Ti(Al)N. High-energy resolved XPS spectra of core levels revealed the formation of Ti–N, Ti–O–N, Si–N and Al–O–N bonds. Comparison of XPS valence band spectra with specially performed density functional theory calculations for disordered Ti0.5Al0.5 N1 − xOx (0 ≤ x ≤ 0.3) phases demonstrated that a Ti(Al)OxNy phase is formed on the surface of AISI430 steel upon the plasma enhanced magnetron sputtering, which can provide a good combination of high hardness and additional oxidation resistance of this material.