Investigation of the structural-phase state and mechanical properties of ZrCrN coatings obtained by plasma-assisted vacuum arc evaporation

Abstract

Introduction. Modern technologies allow the synthesis of nanostructured coatings from multiple chemical elements to combine different physical, mechanical, and chemical properties in one coating. Promising in this respect are coatings formed via layer-by-layer deposition of zirconium and chromium nitrides. The deposition of various chemical elements on various substrates requires separate studies in order to produce high-strength and wear-resistant coatings. The purpose of this work is to study the structural-phase state and mechanical properties of ZrCrN coatings formed by plasma-assisted vacuum arc evaporation. Materials and methods. The investigation is performed on specimens comprising VK8 hard alloy substrates with zirconium and chromium nitride coatings as well as with multilayer ZrCrN coatings. The methods used are confocal laser scanning microscopy, X-ray diffraction analysis, high-resolution scanning electron microscopy, nanoindentation, and scratching. Results and discussion. The experimental results obtained showed that the mode of multilayer ZrCrN coating evaporation greatly affects the structure, morphology, surface roughness, and mechanical properties of the coatings. In particular, by varying the substrate rotation speed during coating deposition it is possible to control the deposition time of each coating layer and thereby modify the layer properties. Conclusions. The investigation results showed that variation of the evaporation conditions allows one to obtain a ZrCrN coating with a high nanohardness of 45 GPa on a VK8 alloy substrate. Analysis of mechanical test results indicate good adhesion between the studied coatings and the substrate. Scratch tests revealed that fracture of CrN and ZrN coatings occurs by the cohesive mechanism, and the surface of ZrCrN coatings exhibits uniform scratches without any signs of fracture. Based on the results obtained, ZrCrN-2…ZrCrN-4 coatings can be recommended for use as hard and wear-resistant coatings.