Effects of thermal treatment and sliding on chemical bonding of PFPE lubricant films with DLC surfaces

The bonding characteristics of polar perfluoropoly(ether) (PFPE) lubricant Z-Dol and nonpolar PFPE lubricants Z-15 and Z-25 with diamondlike carbon (DLC) surfaces were studied. For lubricant Z-Dol, either prebaking the disk before lubrication or a paper pad's being slid on the lubricated disk was found to enhance the bonding capability of lubricant film on the surface of the magnetic disk with DLC coating. For nonpolar lubricants Z-15 and Z-25, a paper pad's sliding on the lubricated disk resulted in some bonding of lubricant molecules on the DLC disk surface. Experimental results were repeatable. The mechanisms of prebaking and sliding responsible for lubricant bonding are discussed, based on the concept of the hydrogen bond interaction and low-energy electron emission, respectively.