Degradation of perfluoropolyether lubricants on magnetic recording disks during sliding

Abstract

Degradation of perfluoropolyether lubricants (Fomblin Z-Dol and Fomblin AM 2001) on the magnetic recording thin-films disks are studied during sliding with an Al2O3-TiC slider under high vacuum. Gaseous products generated from the head/disk interfaces are detected and monitored as a function of sliding distance using a quadrupole mass spectrometer. Effects of overcoats and surface roughnesses of disks on degradation of lubricants and coefficient of friction were also studied. Experimental results show that the gaseous products generated from Z-Dol and AM 2001 lubricants during sliding are quite similar. Degradation of both lubricants is found to take place from the beginning of sliding, and the evolution rate of decomposition fragments decreases with the sliding distance. Removal of the lubricants is accompanied by a rapid rise in the coefficient of friction of the interfaces, followed by gaseous products from the tribochemical reaction of the overcoat material. Surface roughness of the disk has an effect on the sliding distance to failure, but little effect on the decomposition of lubricant.