Influence of Monolayers Thicknesses Ratio on Stability of Structure and Phase Composition of CrN/SiNx Multilayered Coatings under Air Annealing

Abstract

Multilayered CrN/SiNx coatings are formed using the method of magnetron sputtering by the sequential sputtering of Cr and Si3N4 targets upon a variation in the thickness of an individual layer from 2 to 5 nm at a substrate temperature of 450°C. X-ray diffraction analysis demonstrates that multilayered CrN/SiNx coatings consist of nanocrystalline CrN layers with the preferred orientation (002) and amorphous SiNx layers. The lattice parameters of the metal nitride phase for the CrN/SiNx films are greater than for monolytic CrN layers. As wavelength dispersive X-ray spectrometry of the film composition and scanning electron microscopy of the surface have shown, the multilayered CrN/SiNx coatings are more resistant to high-temperature oxidation (in the temperature range of 400–950°C) in comparison with the CrN coatings. This resistance does not essentially depend on the ratio of the thickness of the CrN individual layer to that of the SiNx individual layer. The stability of CrN/SiNx system is compared with the earlier obtained results for ZrN/SiNx system. In general, CrN/SiNx coatings are significantly more stable than ZrN/SiNx coatings under the conditions of high-temperature oxidation