Deposition, structure, and hardness of polycrystalline transition-metal nitride superlattice films

Journal Article · Tue Jun 01 00:00:00 EDT 1999 · Journal of Materials Research

DOI:https://doi.org/10.1557/JMR.1999.0335· OSTI ID:354518

Chu, X; Wong, M S; Sproul, W D; Barnett, S A ^[1]

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1. Department of Materials Science and Engineering and the Advanced Coating Technology Group, Northwestern University, Evanston, Illinois 60208 (United States)

Polycrystalline TiN/VN, NbN/VN, and TiN/NbN superlattices with periods {Lambda} between 2 and 160 nm were deposited onto steel substrates using an opposed-cathode reactive magnetron sputtering system. The nitrogen partial pressure and the substrate bias values were optimized in order to obtain dense stoichiometric films, which yielded the highest Vickers hardnesses H{sub V}. H{sub V} for TiN/VN and TiN/NbN superlattices reached maximum values of {approx}5000 kgf/mm{sup 2} at {Lambda}{approx}5{endash}10&hthinsp;nm, compared with {approx}2000 kgf/mm{sup 2} for homogeneous TiN, NbN, and VN films. In contrast, H{sub V}{approx}2000&hthinsp;kgf/mm{sup 2} was obtained for VN/NbN superlattices independent of {Lambda}. Model calculations in which the hardness enhancement was proportional to the difference in layer shear moduli gave good agreement with the data. The lack of hardness enhancement in VN/NbN indicates that any other hardening mechanisms, such as coherency strains and dislocation blocking by interfacial misfit dislocations, were not important. {copyright} {ital 1999 Materials Research Society.}

• DOE Contract Number: FG02-90ER45434
• OSTI ID: 354518
• Journal Information: Journal of Materials Research, Vol. 14, Issue 6; Other Information: PBD: Jun 1999
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
NIOBIUM COMPOUNDS
VANADIUM COMPOUNDS
TITANIUM COMPOUNDS
NITROGEN COMPOUNDS
TITANIUM NITRIDES
NIOBIUM NITRIDES
VANADIUM NITRIDES
SUPERLATTICES
1-NITROSO-2-NAPHTHOL
CATHODE SPUTTERING
HARDNESS
DISLOCATIONS
STRAINS
DEPOSITION
THIN FILMS
SHEAR PROPERTIES
POLYCRYSTALS
PROTECTIVE COATINGS
USES
MICROSTRUCTURE
MECHANICAL PROPERTIES