Spreading Mechanism of PFPE Lubricant on the Magnetic Disks

The lubrication mechanism when the magnetic head is sliding on the magnetic disk in the drag test with cyclic interval rest periods, is discussed. A long rest period decreased the wear of disks and friction force. This result indicated that the reflow of lubricant into the contact areas decreased the wear of texture asperities. Next, the molecular spreading behavior of a lubricant film was calculated by Monte Carlo method to estimate the effect of lubricant recovering velocities. The lubricant replenishment into a thinner lubricant area made by an etching technique was measured. The measured profiles of lubricant replenishment were approximately agreed with the calculated profiles using a spreading model. It was clearly estimated that the reflow velocities changed in various cases of the environmental temperature, the radius of removal lubricant area, and the thickness of the lubricant films. Experimentally, the dependencies of temperature, the radius of removal lubricant area, and the lubricant thickness were measured in the drag test. This lubricant-spreading model adequately explained these results.