Structure Of Molybdenum Disulfide Films Sputtered On Substrates At Various Temperatures

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In the 1970s and the early 1980s there was an enormous volume of research and development into the subject of molybdenum disulphide lubrication, much of which was supported by national governments for the benefit of defence, aviation or space activities. There were already some well-established practical guidelines for deciding when and how to use molybdenum disulphide, but there was still a considerable lack of universally-accepted theoretical understanding of some of the important and fundamental aspects of molybdenum disulphide technology. However, the state of knowledge was growing rapidly. In the past fifteen years the situation with regard to the technology of molybdenum disulphide lubrication has stabilised in many respects, and a measure of consensus has been reached about some of the mechanisms involved. The use of molybdenum disulphide has become routine in some industries, and there are many well-established and reputable commercial products available. Except in the high-technology field of physical deposition techniques, especially sputtering, the output of new research publications has fallen from perhaps two hundred a year in the 1970s to fewer than ten a year in the 1990s. In spite of this maturing of the subject, it is clear that there are still many aspects in which disagreements persist about the mechanisms involved, and which as a result are unclear or misunderstood among current, and perhaps even more importantly, potential users.One of the primary objectives of this book is to analyse the various aspects of molybdenum disulphide lubrication technology about which there are still disagreements or controversy, and to attempt to come to firm conclusions about some of the mechanisms involved. In particular, it will place emphasis on the importance and effects of burnishing and film consolidation.

Molybdenum disulfide films were deposited by sputtering on both single-crystal molybdenite and steel substrates to assess the effects of varying preparation conditions on film properties. They were then examined by angle-resolved x-ray photoelectron spectroscopy, which provided information on the orientation of the layered crystal substrate, on the film layers immediately adjacent to the substrate (within 1-10 nm), and on thicker, macroscopic films composed of relatively large crystallites (approximately 70-200 nm). For the 4.3-nm-thick films deposited on the crystal's basal-plane surface, the angular dependence of the photoelectron emission is the same as the substrate's, indicating preferred orientation within such films. Angular distribution studies for thicker films on steel substrates are consistent with previous Auger electron spectroscopy results and confirm the presence of oxide films of different thickness of lubricant films with varying orientations. The angle-dependence data were fit to models that describe the structure and composition of the films' surfaces.

Superlubricity is defined as a sliding regime in which friction or resistance to sliding vanishes. It has been shown that energy can be conserved by further reducing/removing friction in moving mechanical systems and this book includes contributions from world-renowned scientists who address some of the most fundamental research issues in overcoming friction. Superlubricity reviews the latest methods and materials in this area of research that are aimed at removing friction in nano-to-micro scale machines and large scale engineering components. Insight is also given into the atomic-scale origins of friction in general and superlubricity while other chapters focus on experimental and practical aspects or impacts of superlubricity that will be very useful for broader industrial community. * Reviews the latest fundamental research in superlubricity today* Presents 'state-of-the-art' methods, materials, and experimental techniques* Latest developments in tribomaterials, coatings, and lubricants providing superlubricity

The crystallinity and morphology of thin, radio-frequency (rf)-sputtered MoS2 films deposited on 440C stainless steel substrates at both ambient (approx. 70 C) and high temperatures (245 C) were studied by scanning electron microscopy (SEM) and by x ray diffraction (Read thin film photography and 0-20 scans). Under SEM, the films exhibited a 'ridgelike' (or platelike) formation region for thicknesses between 0.18 and 1.0 micrometer MoS2. X-ray diffraction was shown to give more detailed and accurate information than electron diffraction previously used for elucidating the structure of sputtered lubricant films. Keywords: Solid lubricant films, Molybdenum disulfide, Radio frequency sputtering, Thin film stress, Lattice defects, X ray diffraction.

This book describes available tribology technologies and introdces a comprehensive overview of tribology. General, up-to-date knowledge on how tribology is approached in various related areas of research, both experimental and computational is provided.