OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 24 No. 3 2022 Introduction Nitride coatings made of either ZrN or CrN possess high mechanical corrosion-resistant and tribological characteristics and therefore are widely used in applications where protection of the base underlying materials against the above mentioned factors is required [1, 2]. In particular, this is especially true for CrN coatings that begin occupying more and more attention of the researchers [3, 4]. Chromium nitride coatings can be obtained using either vapor deposition or arc-ion plating [2]. Zirconium nitride coatings can be used in aero-space applications as thermal or erosion barriers as well as for extending the service life of the metal cutting tools [5]. Cathodic arc ZrN coatings may be used for protection of radioactive waste storage tanks against corrosion [6]. The research literature search shows that there are multilayer coatings containing combinations of alternating metallic, ceramic and amorphous layers. Such an approach allows combining various strength and functional characteristics of the constituent layers for achieving improved synergistic performance of the entire coating. For instance, addition of a CrN layer when preparing the multilayer AlTiN/CrN/ ZrN coatings allowed reducing the residual stresses depending on the CrN layer thickness [7]. Vapor deposition of nanosize thickness CrN/ZrN and CrN/CrAlN layers on stainless steel substrates was carried out to improve the corrosion resistance of the fuel proton exchange membrane cells [8]. It was found that corrosion resistance of CrN/ZrN multilayer coatings proved to be much higher than that of less chemically stable CrN/CrAlN ones. Vacuum-arc deposited ZrN/CrN multilayer coatings with ZrN/CrN bi-layer of different thickness were prepared [9] to show that the thickness reduction allowed increasing the coating hardness while maintaining acceptable the other mechanical characteristics. In addition, the effect of nitrogen atomic concentration on the microhardness and microstructure characteristics of the multilayer coatings was revealed. Summarizing the information reported in the relevant literatures sources it could be stated that the multilayer nitride coatings allow improving mechanical, anti-corrosion and anti-wear characteristics of the substrates [8, 10–15]. Such a conclusion allowed us to suggest that deposition of multilayer ZrN/CrN coatings on the WC-8 wt.%Co cermet has potential for improving the tribological and anti-wear characteristics of the metal processing tools. The objective of this work can be formulated as follows: study texturing and residual macrostresses in the of multilayer plasma-assisted vacuum-arc deposited ZrN/CrN coatings as well as evaluate the applicability of the deposition method inviting both earlier obtained [16] and below disclosed results. Methods and materials A scheme of the plasma-assisted vacuumarc deposition shows the WC-8 wt%Co substrate (Fig. 1, pos. 1) mounted successively on the sample holder (Fig. 1, pos. 2) and table (Fig. 1, pos. 3) inside the vacuum chamber (Fig. 1, pos. 4). Sample holder and table were independently rotated during the deposition as shown by corresponding arrows (Fig. 1, pos. 5) and (Fig. 1, pos. 6), respectively. Such a planetary rotation of the sample was chosen to adapt the deposition of multilayer coatings so that the total sample’s rotation rate was directly proportional to that of the table. The internal vacuum chamber volume was evacuated using a turbomolecular pump (Fig. 1, pos. 7) as shown by the arrow (Fig. 1, pos. 8). An inert gas was then supplied via a plasma torch Fig. 1. Scheme of the plant for a ZrN/CrN multilayer nanostructured coating deposition
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