Advances in Wet Friction Materials 75 Years of Progress

This paper traces the advancements made in wet friction materials. It begins by describing the state of the art prior to the inception of wet friction in 1938. A description is given for the various materials that were required to meet the demands of the equipment manufacturers from then to present day. Also included is a discussion of the roles that spacer plate finish and fluid have played. The paper concludes by describing the performance characteristics of wet friction materials currently available.