OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 24 No. 1 2022 Ta b l e 1 Nanoindentation test results Sample Nanohardness (H), GPa Reduced modulus of elasticity (E), GPa H/E CrN 21.6 335 0.06 ZrN 29.8 394 0.08 ZrCrN-1 34 364 0.09 ZrCrN-2 37.5 359 0.1 ZrCrN-3 39.3 382 0.1 ZrCrN-4 45 436 0.1 Fig. 8. Images of scratches on the surface of coatings: CrN (a), ZrN (b), ZrCrN-1 (c), ZrCrN-2 (d), ZrCrN-3 (e), ZrCrN-4 (f) a b c d e f coatings (Fig. 8a) were scratched with a linearly increasing load. Multilayer ZrCrN coatings exhibit rather uniform scratches without cracks and cleavage. For a more detailed analysis of the effect of indentation on the coatings, the scratch profi les in the region of the deepest pit using the microscope software were evaluated (Fig. 9). The depth of scratches near the cleavage (Table 2) shows that the fracture of CrN and ZrN coatings is cohesive, because the depth of pits is smaller than the thickness of these coatings. The CrN coating fracture begins at a normal indentation load of ~12 N and that of ZrN begins at ~45 N. The tangential force was ~0.8 N for CrN coating and ~2.3 N for ZrN. The change in the indentation depth during testing depends both on the coating properties and on the specifi ed load. The load was set to increase linearly. Therefore, in the ideal case, the penetration of the indenter into the coating should occur in the same manner. However, this quantity slightly fl uctuates in Fig. 10 (scratch length interval from 0 to ~2.3 mm), which is probably due to inhomogeneous surface
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