Nanostructured multi-element (TiZrNbHfTa)N and (TiZrNbHfTa)C hard coatings

Multi-element (TiZrNbHfTa)N and (TiZrNbHfTa)C coatings were deposited on C45 and M2 steel substrates by co-sputtering of pure metallic Ti, Zr, Nb, Hf and Ta targets in Ar + N-2 and Ar + CH4 reactive atmospheres, respectively. TiN, TiC and TiZrNbHfTa metallic coatings were also prepared as reference. All the films were comparatively investigated for elemental and phase composition, texture, microstructure, hardness, friction and wear behavior. X-ray structural analysis revealed the formation of single-solution phases ((111) texture). As compared to the reference binary coatings (TiN and TiC), the multi-component films exhibited significantly higher hardnesses (a difference in hardness of about 10 GPa in the case of nitrides) and also superior wear performance. The best friction and wear behavior was found for the (TiZrNbHfTa)C film, for which the friction coefficient and wear rate were of 0.15 and 0.8 x 10(-6) mm(3) N-1 m(-1), respectively. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.