MICRO NANOSCALE STUDIES OF BOUNDARY-LAYERS OF LIQUID LUBRICANTS FOR MAGNETIC DISKS/

The atomic force/friction force microscope is used to study the micro/ nanotribiological properties of perfluoropolyether lubricants. Single- crystal silicon wafers were lubricated with nonpolar (Z-15) and polar (Z-DOL and Demnum S-100) lubricants. The nanowear tests show that the nonpolar (2-15) lubricant depleted from the wear track within a few cy cles, whereas polar (Z-DOL) lubricant exhibits excellent nanowear resi stance with no degradation. The polar lubricant results in a lower val ue of microfriction as compared to the nonpolar lubricant and unlubric ated silicon sample. The effect of thickness of polar lubricant is stu died for the thermally bonded Z-DOL lubricant before and after wash. U nwashed polar lubricant film with unbonded fraction exhibited better r esistance to wear than that of washed lubricant film. Thicker films ar e also more durable. Wear experiments with magnetic disks show that lu bricant films on a super smooth disk is more effective in reduction of friction and wear than a smooth disk. Coefficient of friction on micr o- and macroscales are compared. Variation in lubricant film thickness results in variation in coefficient of friction. Thus, friction force microscopy can be used to measure lubricant uniformity with spatial r esolution on the order of tens of nm. Finally, adhesive experiments sh ow that bonded film behaves as a soft polymeric solid. (C) 1996 Americ an Institute of Physics.