Formation of superhard Ti-Hf-Si-N/NbN/Al2O3 multilayer coatings for highly effective protection of steel

Hard micro- and nanostructured Ti-Hf-Si-N/NbN/Al2O3 multilayer coatings on steel substrates have been obtained for the first time using various deposition technologies and characterized by a combination of methods. It is established that the proposed coatings possess, in addition to high hardness (H = 47–56 GPa), high elastic modulus (E = 435–570 GPa), and good plasticity index (W e = 0.08–0.11), a rather low friction coefficient that varies within μ = 0.02–0.001 depending on the deposition conditions. The coatings remain stable at temperatures above 1000°C.