WEAR AND DEGRADATION MECHANISMS OF MAGNETIC THIN-FILM RIGID DISKS WITH DIFFERENT LUBRICANTS USING MASS-SPECTROMETRY

Wear and degradation mechanisms of perfluoropolyether (PFPE) lubricant s are studied using mass spectrometry and friction measurements during sliding in a high vacuum environment. Three kinds of lubricants with nonpolar and polar ends and with and without thermal treatment are app lied over a thin-film disk with diamondlike film (DLC) overcoat. The r esults show that fluorocarbon fragments are generated from lubricants during a period of sliding with a low and stable coefficient of fricti on, followed by a sharp rise in frictional force and generation of gas eous products of DLC overcoat material. Increase in the friction is as sociated with lubricant depletion leading to intimate contact of the s lider with the DLC overcoat. It is concluded that decomposition of PFP Es begins from the onset of sliding, and the DLC overcoat starts to we ar simultaneously from the beginning of the sliding for untreated lubr icants, but was well protected in the case of chemically bonded lubric ants. Fully bonded lubricants better protect the DLC followed by parti ally bonded lubricants. Two bonded lubricants tested, exhibited simila r performance. (C) 1997 American Institute of Physics.