AVS 46th International Symposium
    Vacuum Metallurgy Division Tuesday Sessions
       Session VM+MI+AS-TuA

Paper VM+MI+AS-TuA7
Interaction of Fluoroalcohols and Fluoroethers with Various Types of Carbon Overcoats

Tuesday, October 26, 1999, 4:00 pm, Room 620

Session: Magnetic Recording: Head/Disk Interface and Overcoats
Presenter: N. Shukla, Carnegie Mellon University
Authors: N. Shukla, Carnegie Mellon University
A.J. Gellman, Carnegie Mellon University
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This work is focussed on understanding the fundamentals of head-disk interface tribology at very low flying heights and higher spin rates. Since there will be room for only a single molecular monolayer of the lubricant on the disk surface at low flying heights we have studied the molecular level interaction of lubricants with carbon overcoats that protect the disk surface. We have modeled a most commonly used PFPE lubricant (Fomblin Zdol) using short chain model compounds and measured the desorption energy of these compounds on carbon films. The short chain model compounds used are 2,2,2 trifluoroethanol (CF@sub3@CH@sub2@OH) and perfluorodiethyl ether (CF@sub3@CF@sub2@OCF@sub2@CF@sub3@) which are representative of both the end group and the main chain of Fomblin Zdol. Temperature programmed desorption spectroscopy is used to measure the desorption energy of model compounds and also to understand the nature of the interaction of these short chain compounds with carbon overcoats. Initial results show that ethers interact with carbon overcoats through electron donation from the oxygen lone pair electron and the alcohols interact with carbon overcoats through hydrogen bonding. In addition we have studied the effect of various film compositions on the interaction of the lubricants in order to understand if the film composition has any effect on the nature of the bonding of the lubricant. The different types of overcoats used are hydrogenated, nitrogenated, diamond-like carbon and Ion beam sputtered overcoats. We have observed that by varying the percentage of hydrogen or nitrogen content in the film composition or by changing the carbon overcoat deposition conditions as in diamond like carbon overcoats or in an ion beam sputtered overcoat there is no significant change in the interaction of the lubricant with carbon overcoat. The alcohols however bond stronger than ethers on all overcoats, which is consistent with the structures, proposed by diffusion measurements.