ISSN 1063-7850, Technical Physics Letters, 2013, Vol. 39, No. 2, pp. 189–192. © Pleiades Publishing, Ltd., 2013. Original Russian Text © A.D. Pogrebnyak, V.M. Beresnev, A.Sh. Kaverina, A.P. Shypylenko, O.V. Kolisnichenko, K. Oyoshi, Y. Takeda, H. Murakami, D.A. Kolesnikov, M.S. Prozorova, 2013, published in Pis’ma v Zhurnal Tekhnicheskoi Fiziki, 2013, Vol. 39, No. 4, pp. 9–16. 189 Nanostructured multicomponent and multilayer coatings provide a basis for solving numerous prob- lems related to the protection of articles made of vari- ous functional materials [1–4]. As is well known, Al 2 O 3 -based ceramic coatings exhibit high resistance to aggressive and oxidative media and ensure protec- tion of coated parts operating at high temperatures [5]. In this context, the development of a new generation of micro- and nanostructured multilayer coatings pos- sessing high mechanical and tribological properties for increasing the spectrum of protective functions is a topical task of solid state physics and materials sci- ence. The layer of Al 2 O 3 was deposited using a two- chamber cumulative detonation setup [6]. The initial material was AMPERIT 740.0 Al 2 O 3 powder with the main fraction sizes within 5.6–22.6 μm and 5% of par- ticles with characteristic sizes of ≥50 μm. The next layer was deposited using an RF-stimulated vacuum arc with a Ti–Hf–Si cathode in nitrogen. The process was controlled by varying the bias voltage and residual gas pressure. The intermediate nitride layer was syn- thesized using gaseous nitrogen. Thus, the Al 2 O 3 layer thickness was about 180 μm, the NbN interlayer was about 1.2 μm thick, and the (Ti–Hf–Si)N layer thick- ness was varied from 5 to 12 μm. The microstructure and elemental composition of deposited coatings was studied using Quanta 200 3D and Quanta 600 SEM (United States) scanning ion- electron microscopes, equipped with a PEGASUS 2000 X-ray detector system for energy-dispersive X- ray spectroscopy (EDS) measurements, and a JEOL 7000F (Japan) scanning electron microscope (SEM). The Vickers microhardness was measured in a coat- ing/substrate section using a DM-8 automated hard- ness analyzer at an indenter load of 25 and 300 g. Mea- surements of the nanohardness and elastic modulus were performed on a Nanoindenter G200 (MES Sys- tems, United States) using a Berkovitz trihedral dia- mond pyramid. The porosity of coatings was determined using a metallographic technique involving qualitative and quantitative analysis of pore geometry with the aid of an Olympus GX51 inverted optical microscope. The structure and phase compositions of deposits were studied by measuring X-ray diffraction (XRD) at graz- ing incidence on a Rigaku RINT-2500-MDG instru- ment using radiation from chromium anode. The ele- mental composition of coatings was studied by Auger electron spectroscopy on a Profile-2 glow-discharge mass spectrometry CGMS setup. Tribological investi- gations were carried out using a REVETEST (GSM Instruments, Switzerland) scratch testing instrument, which measured the friction coefficient μ, wear resis- tance, and acoustic emission induced by Rockwell-C pyramid indentation. The surface of a coating/substrate section was etched by a 3% ethanol solution of nitric acid. As a result, active components of the boundary material were dissolved and the section revealed a mixed struc- ture of the interface (Fig. 1a) comprising islands of the coating material of various shapes and dimensions on Formation of Superhard Ti–Hf–Si–N/NbN/Al 2 O 3 Multilayer Coatings for Highly Effective Protection of Steel A. D. Pogrebnyak*, V. M. Beresnev, A. Sh. Kaverina, A. P. Shypylenko, O. V. Kolisnichenko, K. Oyoshi, Y. Takeda, H. Murakami, D. A. Kolesnikov, and M. S. Prozorova Sumy State University, 40007 Sumy, Ukraine Kharkiv National University, 61002 Kharkiv, Ukraine Paton Electric Welding Institute, National Academy of Sciences of Ukraine, 03680 Kiev, Ukraine National Institute for Materials Science, Tsukuba-city, Ibaraki, 305-0047 Tsukuba, Japan Belgorod State University, Belgorod, 308015 Russia *e-mail: alexp@i.ua Received September 22, 2012 Abstract—Hard micro- and nanostructured Ti–Hf–Si–N/NbN/Al 2 O 3 multilayer coatings on steel sub- strates have been obtained for the first time using various deposition technologies and characterized by a com- bination 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 coat- ings remain stable at temperatures above 1000°C. DOI: 10.1134/S1063785013020223