Soluble additives for perfluorinated lubricants

High-performance aerospace systems make severe demands on lubricants. Among the potential candidates, perfluorinated fluids, especially perfluoropolyethers (PFPEs), lead the list. PFPEs are unique in that several of the properties required for the lubrication of these systems, such as thermalloxidation stability, chemical inertness, compatibility with materials of construction, high viscosity index, etc., are inherent to them. However, there is a need to add other characteristics or to improve some of the inherent properties. Research programme to find a solution by preparing PFPEs with different structures as well as developing soluble anticorrosion, antiwear, and stabilising additives has been undertaken. The present paper describes the preliminary results obtained with a few additives and suggests possible action mechanisms.