Effect of lubricant bonding fraction at the head-disk interface

Tribochemical studies of the effect of lubricant bonding on the tribology of the head-disk interface (HDI) were conducted using hydrogenated (CHx) carbon disk samples coated with perfluoropolyether ZDOL lubricant. The studies involved drag tests with uncoated and carbon-coated Al2O3-TiC sliders and also thermal desorption experiments in an ultrahigh vacuum (UHV) tribochamber. The friction and catalytic decomposition mechanisms as well as the thermal behavior of ZDOL are described. We observed that a larger mobile lubricant portion significantly enhances the wear durability of the HDI by providing a reservoir to constantly replenish the lubricant displaced in the wear track during drag tests. In the thermal desorption tests we observed two distinct temperatures of desorption. The mobile ZDOL layer is desorbed at the lower thermal desorption temperature and the residual bonded ZDOL layer is desorbed at the higher thermal desorption temperature.