Superhard CrN/MoN coatings with multilayer architecture. (5th September 2018)

• Record Type: Journal Article
• Authors: Pogrebnjak, A.D.; Beresnev, V.M.; Bondar, O.V.; Postolnyi, B.O.; Zaleski, K.; Coy, E.; Jurga, S.; Lisovenko, M.O.; Konarski, P.; Rebouta, L.; Araujo, J.P.
• Is Part Of: Materials & design. Volume 153(2018)
• Page Start: 47
• Page End: 59
• Publication Date: 2018-09-05
• Subjects: Multilayers -- Microstructure -- Phase composition -- Hardness -- H/E ratio -- Wear; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2018.05.001
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: Main regularities of the formation of microstructure and properties of multilayer nanostructured CrN/MoN films with periodically changing architecture of layers were considered. Coatings were fabricated by vacuum-arc evaporation of the cathodes (Arc-PVD) in nitrogen atmosphere (pN was 0.4, 0.09 and 0.03 Pa). CrN and γ-Mo2 N nitride phases with fcc lattices and a small volume of metastable MoNx cubic phase were formed in the films at pN = 0.4 Pa. The decrease of pN to 0.09 Pa causes the formation of β-Cr2 N hexagonal phase. Preferential crystallographic orientation changes from [311] to [111] and [200] when bias voltage Ub is −20, −150 and −300 V respectively. The nanocrystallites size in coatings with bilayer thickness λ = 44 nm decreases to 5.8 nm. The microdeformation grows from 0.4 to 2.3% when Ub changes to −20 V. Coatings show high hardness of 38–42 GPa and H/E = 0.107. In a couple with results of tribological tests, coatings demonstrate strong wear resistance, which makes them appropriate and promising for industrial applications as protective ones. The effect of deposition conditions (pN, Ub, λ) on composition, structure, hardness, toughness and wear resistance was studied to achieve superior mechanical and physical properties of coatings with long lifetime in harsh environment. Graphical abstract: Unlabelled Image Highlights: Superhard protective CrN/MoN films were studied and approved as appropriate for industrial applications. Preferred orientation changes from [311] to [111] and [200] when bias voltage is -20, -150 and -300 V respectively. Decrease of pN to 0.09 Pa causes the formation of β-Cr2 N hexagonal phase additionally to cubic CrN, γ-Mo2 N and MoNx . Coatings showed high hardness up to 38-42 GPa, ratio H/E = 0.107 and high wear resistance according to tribological test. The best tested deposition conditions: Ub = -20 V, pN = 0.4 Pa and individual layer thickness is 22 nm.