AVS 58th Annual International Symposium and Exhibition
    Tribology Focus Topic Thursday Sessions
       Session TR-ThP

Paper TR-ThP8
Parameter Optimization of Ion Plated Nickel-Copper-Silver Lubrication

Thursday, November 3, 2011, 6:00 pm, Room East Exhibit Hall

Session: Tribology Focus Topic Poster Session
Presenter: Mike Danyluk, University of Wisconsin Milwaukee
Authors: M. Danyluk, University of Wisconsin Milwaukee
A. Dhingra, University of Wisconsin Milwaukee
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In this paper we present a connection between argon ion flux with ion mixing and rolling contact fatigue (RCF) life of a thin solid nickel-copper-silver film lubrication on ball bearings tested in high vacuum. Using a Langmuir probe we measure plasma properties and ion flux and then calculate plane stress within the film during deposition using a validated model found in the thin film science literature. Experiments reveal that there is an inverse relationship between ion flux and RCF life for most deposition voltage and pressure combinations tested, specifically, 15.5 to 18.5 mTorr and 1.5 to 3.5 kV. For voltages up to 2.5 kV, RCF life decreases as deposition voltage and ion flux increase. Experiments also confirm that as ion flux increases deposition rate decreases due to sputter removal from the ball surface. For voltages between 2.5 and 3.5 kV interlayer mixing and contamination of the 100 nm thick coating reduces RCF life even as ion flux decreases with decreasing process pressure within a constant power process. At ion energy greater than 2.5 keV and ion flux above 1015 cm-2 s-1, SRIM results suggest elemental mixing of copper and nickel at the interface and this is confirmed using Auger Electron Spectroscopy (AES) on steel and Si3N4 5/16” diameter balls.