AVS 47th International Symposium
    Surface Engineering Monday Sessions
       Session SE+TF-MoM

Paper SE+TF-MoM6
Thermal Stability and Mechanical Properties of Nano-scale W/ZrN Multilayers

Monday, October 2, 2000, 10:00 am, Room 201

Session: Hard and Superhard Coatings
Presenter: A. Madan, Northwestern University
Authors: A. Madan, Northwestern University
J. Ji, Applied Thin Films, Inc.
S.A. Barnett, Applied Thin Films, Inc.
Correspondent: Click to Email
Nanolayered thin films show an enhanced hardness and improved mechanical properties as compared to the individual layer components. The high-temperature stability of these films is important for various technological applications e.g. dry-cutting. We report on the thermal stability and mechanical properties of polycrystalline, immiscible W/ZrN nanolayered films. W/ZrN multilayers of bilayer periods 2 to 40 nm were sputter deposited in a dual-opposed-cathode unbalanced-magnetron sputtering system. The W fraction was varied from 0.3 to 0.8 by adjusting the relative power on the two targets. The 1 micron films were annealed at temperatures from 750°C to 1000°C in inert atmospheres. The as-deposited and the annealed films were characterized using x-ray diffraction, cross-sectional transmission electron microscopy (XTEM), and nanoindentation. The as-deposited films showed an enhanced hardness in comparison to the rule-of-mixtures values irrespective of the bilayer period or the layer composition ratio. High- and low-angle x-ray diffraction (XRD) showed that the layered structure was stable after annealing at 1000°C for 1 h. XTEM results for as-deposited and annealed films will be presented. The annealed films show hardnesses as high as 44 GPa. The excellent high-temperature stability of the W/ZrN nanolayered structures arises because W and ZrN are mutually immiscible.