A research program is proposed that addresses a number of critical tribological issues that arise in the lubrication of magnetic data storage media. As the areal density of data stored on hard disk surfaces increases, the gap between the read-write head and the disk surface must decrease. The gap is currently <20 nm and predictions are that in order to store data at densities of 1 Tbit/in^2 the gap will have to be reduced to < 5 nm. A thin film (1 - 2 nm) of liquid lubricant on the disk surface is critical for protection of the disk surface during intermittent high speed head-disk contacts. As the gap between the head and the disk decreases, the demands on the performance of this lubricant film increase and the tolerances on its characteristics grow tighter and tighter. The proposed research program explores some of the fundamental scientific issues that must be understood in order to develop a new vapor phase method for applying lubricant to the disk surface under highly controlled vacuum conditions. The proposed research program is an industry-university collaboration that will develop the physico-chemical understanding of the properties of lubricant films deposited on the freshly sputtered amorphous carbon overcoats that cover the media surface. This research is made possible by a newly built apparatus that emulates the vapor deposition process while also allowing study of the surface properties and the surface chemistry of lubricant films vapor deposited onto amorphous carbon (a-C) overcoats. Oxidation of freshly sputtered a-C overcoats will be studied in order to determine the kinetics of oxidation and to identify some of the species produced on the a-C surface during exposure to O2 and H2O. The adsorption of fluorinated ethers and alcohols with fresh and oxidized a-C films will be studied in order to understand the bonding of perfluoropolyalkylether (PFPE) lubricants with fresh and oxidized a-C surfaces. Finally, the surface chemistry and surface properties of PFPE lubricants themselves will be studied on the surfaces of fresh and oxidized a-C surfaces. Understanding the differences between PFPE lubricants on the freshly deposited a-C films and air-exposed a-C films is needed in order to help the development of the vapor lubrication process and its transition into practice. The impact of the proposed project extends quite broadly beyond the development of a fundamental understanding of the science underlying the emerging technology of vapor lubrication. The proposed research will have a direct impact on the technology itself and the PI's connections with the data storage industry will enable the results of the work to be directly disseminated to the scientists and engineers within the data storage industry who will transfer this technology into the commercial sector. The rapid development of this technology will help the U.S. data storage industry to maintain its leadership position in an extremely competitive sector. The PI, the co-PIs and students meet quarterly with the members of the Information Storage Industries Consortium (INSIC) and with the members of Carnegie Mellon's Data Storage Systems Center (DSSC). These meetings serve as venues for dissemination of research results and for feedback from industry while also providing an excellent opportunity for educating, training, and exposing students to developments in data storage.
