An overview of fluoride-based solid lubricants in sliding contacts

The application of fluoride-based solid lubricants in wear resistant materials is increasing rapidly, especially in advanced materials that need to operate at elevated temperatures. However, a concise and consistent discussion on this important class of fluoride lubricants and their tribological characteristics in advanced materials is not available. This review aims to provide a comprehensive discussion on various fluoride solid lubricants used as additive in a composite material or as coatings at a wide range of operating conditions. A brittle-ductile transformation above similar to 400 degrees C allows their lubricating nature. Furthermore, fluorides provide a synergistic effect if they react with other metallic or non-metallic compounds at high temperature. Finally, this article highlights the industrial applications of fluoride solid lubricants in wear resistant components.