Simultaneous measurement of pin wear and change in lubricant thickness on thin-film magnetic disks

The relation between head wear and disk-lubricant thickness was studied by transparent pin wear tests on thin-film magnetic disks while making simultaneous micro-ellipsometer measurements to determine changes in lubricant thickness. As-dipped and rinsed lubricant disks were prepared to study the effects of free and adsorbed lubricants. On the rinsed disk without free lubricant, pin wear started after one minute of sliding, and the decrease in lubricant thickness on the sliding track was small. On the as-dipped disk with free lubricant, pin wear started after 30 minutes of sliding, and was less pronounced than that on the rinsed disk, while lubricant thickness decreased until wear started, and became constant thereafter. The decrease in lubricant thickness was greater than that on the rinsed disk. Free lubricant was shown to reduce pin wear. The replenishment of lubricant was also measured. A model of pin wear and change in lubricant thickness is proposed taking into account disk-surface roughness and the replenishment of free lubricant.