Fundamentals of dry friction and some practical examples

Dry sliding of different components over each other results in changes of interfaces. During the running‐in procedure a surface accommodation takes place. There is transfer of material from the softer to the harder component. At the surface of a composite a friction layer is formed, which has a different chemistry than the matrix. Type of friction layer and transfer layer govern the tribological performance of a dry sliding system. In order to arrive at desired frictional properties various additives are added to composites. Change of tribological performance by use of solid lubricants in dry bearings, carbon brushes and brake linings is discussed.