Application of highly entropic coatings at simultaneous spraying of three cathodes in one cycle

Abstract

In this work, we consider the application of highly entropic coatings while simultaneously sputtering three cathodes in a single cycle. The cathodes 12Cr15G9ND, Cu, Al were chosen as cathodes. The chemical composition of the cathodes was measured using a TESCAN MIRA 3 electron microscope. Using these cathodes, coatings were applied to polished samples of steel 45 in an NNV-6.6 I1 vacuum ion-plasma apparatus. The measurement was carried out using a MIRA 3 scanning electron microscope, an HVS-1000A microhardness tester, and a tribological research facility. SEM images show that with an increase of ×5000 or more, the droplet phase is clearly detected. The maximum size of the droplet phase reaches 12.0 μm with a variety of morphometric parameters varying, for example, in a geometry coefficient K from 0.8 to 1.0. Analysis of the coating at high magnifications (×7000 and ×20,000) without the droplet phase showed that the grain sizes of the coating are as follows: minimum — 0.23 microns, maximum — 0.65 microns (average of about 0.47 microns); while the coating structure is homogeneous. The analyzed type of structure refers to the zone of the so-called «competing texture», when a dense nanocrystalline structure is present in the lower region of the film, and a columnar structure is above it. The results of this study allow us to conclude that the simultaneous deposition of deposited cathodes of various metals (especially composite) in principle allows to obtain highly entropic coatings. Two points must be taken into account here: firstly, the number of atomized cathodes must be increased; secondly, it is necessary to take into account the values of the erosion coefficient for the cathodes used so that the atomized fluxes are equimolarly proportional. Measurements of coatings showed that the microhardness of Cu+Al+12Cr15G9ND is not inferior to ordinary steels, but of course it lags behind nanostructured coatings (30–50 GPa). The proposed coatings have antifriction properties of 3 or more times and can be used in tribological pairs.