Advanced solid lubricant coatings for high vacuum environments

Abstract

Solid lubricant coatings for vacuum applications have seen considerable developments for many years, because of the use of advanced coating techniques, such as physical or chemical vapor deposition processes. The need for fully understanding the relationships between the nature of the lubricant coatings and their tribological performances in relation to the nature of the environment during sliding has become more pressing. The present paper discusses and compares the friction behavior of two kinds of thin film solid lubricant (pure MoS 2 and hydrogenated diamond-like carbon (DLC)) from a pressure range less than 5×10 −8 hPa to ambient air. Friction coefficient values less than 0.15 in ambient air and less than 10 −2 in ultrahigh vacuum have been recorded using pin-on-fiat tribometers. Present results are also compared with previous work published by others. The potentiality of DLC coatings used as solid lubricant for space applications is thus highlighted, in comparison with the more extensively used MoS 2 coatings.