Modern solid lubrication: Recent developments and applications of MoS₂

Abstract

Abstract An important and growing field of lubrication lies in the use of solid films, although they are in general more expensive than oils or greases, and require specialist attention both in mechanical design and in coating application techniques. In this paper, the general classification of solid lubricant types is reviewed, along with the reasons for choosing, and methods of depositing, solid lubricants, in particular MoS 2 . The best‐performing and most flexible technique for making MoS 2 films is by physical vapour deposition (PVD), and the variants of that technology are considered. The intrinsically lubricating, lamellar structure of pure MoS 2 is described, along with a brief summary of its wear and failure modes. Present applications for lubrication by MoS 2 in spacecraft and dry machining are outlined, as are anti‐adhesive uses in extruding and moulding. The current state of the art of modification of MoS 2 films consists in the addition of dopants (co‐sputtering), in multilayering as a series of films, each fulfilling a specific task, or in stacking repeating nano‐metre‐scale films. Composite films of MoS 2 islands in a hard film matrix are also being developed.