Effects of backbone and endgroup on the decomposition mechanisms of PFPE lubricants and their tribological performance at the head-disk interface

Tribo-chemical studies of the lubricant endgroup effect on the tribology of the head-disk interface were conducted using carbon disks coated with PFPE lubricant. The studies involved drag rests with uncoated and carbon-coated Al2O3-TiC sliders in an ultrahigh-vacuum (UHV) tribochamber. The UHV drag rests show that a good lubricant should have one active OH endgroup and one nonactive endgroup. The active one insures the lubricant is adsorbed very well onto the disk carbon surface, resulting in a lower removal rate of the lubricants during the contact sliding. The nonactive one prevents the cata lytic decomposition of the lubricant in the presence of the Al2O3 surface o f the uncoated slider. The studies also demonstrate that the catalytic degr adation process of ZDOL in the presence of Lewis acid occurs most readily a t the acetal units (-O-CF2-O) within the internal backbones (CF2O and CF2CF 2O) instead of the endgroup functionals, Therefore, demnum, without any ace tal units, experiences less catalytic degradation with the uncoated Al2O3/T iC sliders as compared to ZDOL.