Applications of Surface Science to Solid Lubricants

摘要

Solid lubricants fill a very important niche in the world of tribology byproviding low-friction surfaces under harsh operating conditions, such as high or very low temperature and high vacuum. The successful use of solid lubricants in most applications relies on controlling the chemical interactions occurring at several interfaces, and the use of surface science techniques to study and understand these chemical interactions has become increasingly more important in recent years. In this report, the surface properties of molybdenum disulfide (MoS2), the most widely used solid lubricant for space applications, are studied with a variety of techniques. The techniques discussed are: valence band photoelectron spectroscopy (PES) to determine electronic structure properties; scanning tunneling and atomic force microscopies to examine surface structure; high-resolution electron energy loss spectroscopy to determine surface phonon properties; core level PES with synchrotron radiation to study metal/MoS2 interfacial chemistry; core level X-ray photoelectron spectroscopy to study steel and ceramic substrate chemistry; and extended X-ray absorption fine structure, electron microscopies, and X-ray diffraction to study film structure. In addition, theoretical and tribological studies of MoS2 are discussed. The goal of this work is to develop a fundamental understanding of the electronic structure and reactivity of MoS2 as determined by these surface science techniques, and to relate this fundamental understanding to the performance Of MoS2 as a solid lubricant.... Tribology, Solid lubricants, Surface science, Surface chemistry, Synchrotron radiation, Photoelectron spectroscopy, Molybdenum.