Friction and Wear Properties of MoS2 Thin-Film Lubricants
Abstract
The generally agreed upon mechanism for lubrication of sliding and rolling contacts by MoS2 thin films consists of the movement of crystallites (micro or nanocrystals) over one another with friction determined by the interactive forces between the basal planes of individual crystallites and wear by the eventual loss of material in the contact. It has been proposed that long life can be achieved by the recirculation of crystalline material into the contact area from reservoirs of lubricant (debris) that accumulate outside of the contact. Chemical and structural (morphological) properties of films have been implicated in determining friction and wear behavior, but the relationship between these properties and the intercrystalline slip lubrication mechanism has not been clarified. In this paper we review data on the results of thrust-bearing tests of sputter-deposited films, specifically as they relate to test environment, and attempt to provide a chemistry-based model of lifetime variation. We present new data on lubricant transfer-film formation and the effects of test environment, from which we propose that bearing life is determined by the efficiency of chemical bonding between MoS2 'debris' and uncoated or worn metal surfaces.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 2002
- Accession Number
- ADA401523
Entities
People
- J. R. Lince
- P. D. Fleischauer
- S. V. Didziulis
Organizations
- The Aerospace Corporation