Study of RF PACVD diamond-like carbon coatings for space mechanism applications

Currently, sputtered molybdenum disulphide is an established coating in the field of space applications. However, when used in air, molybdenum disulph ide loses much of its lubricating power, thus preventing in-air ground test ing. In this work, the tribological properties in vacuum, dry N-2 and air of a-C :H films produced by radio frequency plasma assisted chemical vapour deposi tion (RF PACVD) were studied in order to assess their potential for applica tions in space. We demonstrated that diamond-like carbon (DLC) films deposi ted at low bias voltage show lubricating capacity under vacuum conditions. However, the shorter lifetime of these DLC films compared to MoS2 under vac uum is considered to be an important limiting factor. (C) 1999 Elsevier Sci ence S.A. All rights reserved.