Structure and Properties of ZrON Coatings Synthesized by Cathodic Arc Evaporation

Abstract

The transition metal oxynitrides are a coating material with decorative features due to their adjustable color and good mechanical properties. The purpose of the research was to study the effect of the relative oxygen concentration O2(x) = O2/(N2 + O2) in particular on adhesion, but also on the color, structural and mechanical properties of ZrON coatings synthesized by cathodic arc evaporation on HS6-5-2 steel substrates. The surface morphology, phase and chemical composition and mechanical properties were determined using scanning electron microscopy, X-ray diffraction, wavelength dispersive X-ray spectroscopy, nanoindentation and scratch test. It was found that color of the coatings changed from light yellow for ZrN first to gold and then to graphite for Zr-O phase with increase of oxygen concentration. X-ray diffraction patterns showed that the phase separation of ZrN and ZrO2 occurred for about 35 at.% of oxygen in the coating. Increase in oxygen concentration in the coatings led to decrease in crystallite size from about 20 nm for ZrN to about 5 nm for coatings with about 35 at.% of oxygen and about 25 at.% of nitrogen. An increase in hardness from about 26 GPa for ZrN to about 30 GPa for coating with small concentration of oxygen (about 9 at.%) and then decrease to about 15 GPa was observed. Adhesion of Zr-O-N coatings demonstrated strong dependence on oxygen concentration. Critical load for ZrN is about 80 N and decreases with oxygen concentration increase to about 30 N for ZrO2.

Corrosion Improvement of 304L Stainless Steel by ZrSiN and ZrSi(N,O) Mono- and Double-Layers Prepared by Reactive Cathodic Arc Evaporation

“…Despite the quite low oxygen content in the Zr(N,O) coating, its diffractogram exhibited (in addition to the presence of the cubic structure of ZrSiN previously reported in the literature [69,70]) a low intensity peak ascribed to the (101) maximum of the tetragonal ZrO 2 phase (space group P42/nmc), according to ICDD file #68-0200. The same observation was previously reported for ZrON coatings prepared by cathodic arc evaporation [43]. The small peak is also visible on the SS/ZrSiN/ZrSi(N,O) diffractogram, as the top layer was an oxynitride.…”

“…The grain size (d) of the ZrSiN coating decreased with oxygen addition of about 30%, indicating a certain refinement, as previously reported for a Zr(N,O) single layer obtained with the same deposition method [43]. The bilayers presented intermediate values (SS/ZrSiN/ZrSi(N,O) (d) = 12.4 nm and SS/ZrSi(N,O)/ZrSiN (d) = 13.2 nm), but the calculated grain size of the bilayers represented the averaged value of each component layer, and the small difference between their calculated values, of about 6%, was ascribed to the X-ray absorption in the upper layer.…”

“…The grain size (d) of the ZrSiN coating decreased with oxygen addition of about 30%, indicating a certain refinement, as previously reported for a Zr(N,O) single layer obtained with the same deposition method [43] The incorporation of oxygen into the ZrSiN structure was clearly evidenced by a further shift of the ZrSiN peaks towards even smaller diffraction angles due to the lattice expansion needed to accommodate the presence of oxygen in the interstitial sites. Despite the quite low oxygen content in the Zr(N,O) coating, its diffractogram exhibited (in addition to the presence of the cubic structure of ZrSiN previously reported in the literature [69,70]) a low intensity peak ascribed to the (101) maximum of the tetragonal ZrO 2 phase (space group P42/nmc), according to ICDD file #68-0200.…”

“…Because the properties of transition metal oxynitrides are related to their oxygen/nitrogen ratio, they can be customized by modifying this ratio [41,42]. Additionally, it was shown that lattice strain, deformation stress, and deformation energy density depend on oxygen pressure [43].…”

Indentation of Thin Coatings: Theoretical and Experimental Investigation

“…This method is also used to study the mechanical properties of biological tissues [9]- [12]. In addition, in some cases, the use of this method provides predictable results when indenting material layers, when the penetration depth does not exceed 10% of its thickness [13]- [15]. However, with a significant difference in Young's moduli of the layers, the reconstructed value of Young's modulus can be noticeably underestimated or overestimated.…”