In situ quantitative analysis of nano-scale lubricant migration at the slider–disk interface

A thin layer of lubricant is a critical element of the head/disk interface needed to improve its tribological durability and to prevent media corrosion. Local thinning of lubricant with its subsequent breakdown often leads to the immediate failure of the interface. This paper is devoted to the in situ quantitative analysis of nano-scale lubricant migration on the surface of a thin-film disk using the Optical Surface Analyzer (OSA). The calibration procedure, which enables quantitative measurements, is discussed and the technique's capabilities are demonstrated using specially prepared samples. Two cases of slider/disk interaction are analyzed: low-speed, when the slider is dragged over the disk surface, and high-speed, when the slider is flown over the same track for several days. Lubricant migration phenomena, such as depletion and pooling, are investigated quantitatively to analyze the origination of carbon wear and the mechanisms of interfacial failure. A model of high-speed slider/disk interaction involving the dynamic formation of a liquid bridge at the interface is proposed. (C) 1999 Elsevier Science S.A. All rights reserved.