AVS 47th International Symposium
    Thin Films Tuesday Sessions
       Session TF-TuP

Paper TF-TuP30
Properties of Multicomponent Transition Metal Carbide Coatings Prepared by Magnetron Sputtering

Tuesday, October 3, 2000, 5:30 pm, Room Exhibit Hall C & D

Session: Poster Session
Presenter: S.H. Koutzaki, University of New Hampshire
Authors: S.H. Koutzaki, University of New Hampshire
J.E. Krzanowski, University of New Hampshire
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The mechanical and tribological properties of conventional carbide hard coating materials can potentially be improved by developing multicomponent films with nano-scale microstructures. However, the microstructures and phases that form in PVD thin films are often far from equilibrium, so it is necessary to investigate these aspects of candidate multicomponent systems in order to assess their potential as nano-structured hard coatings. Two multicomponent metal carbide systems were investigated in this study, Ti-Mo-C and Ti-W-C. Coatings were fabricated by RF co-sputtering from carbide targets using target combinations of TiC-Mo2C and TiC-WC. Films were deposited on silicon and sapphire substrates at temperatures ranging from room temperature to 650C. The coatings were characterized by XPS, X-ray diffraction, TEM, and nanoindentation. For Ti-Mo-C films, nearly all film compositions were supersaturated solid solutions of Mo in TiC, and multiphase structures could only be obtained in highly Mo-rich films. The hardness of these films generally did not improve with Mo content. Films deposited from TiC and stoichiometric a-WC targets formed only (Ti,W)C solid solutions. The hardness of the sputtered Ti-W-C coatings was in the range of 15-17 GPa, with the exception of one Ti-W-C (40 %W) that had a hardness of 30 GPa. This latter sample was examined using high-resolution TEM, and in comparison to the other Ti-W-C films, was found to have a significantly smaller grain size and a higher film density.