Third Body Concept and Wear Particle Behavior in Dry Friction Sliding Conditions

The third body concept is a pragmatic tool for analyzing and understanding the friction and wear of sliding materials. This approach is based on the dominating role played by the wear particles under dry sliding conditions. These particles constitute the major part of what is called the third body. The third body concept was introduced by Maurice Godet in the middle of the 70’s and developed by Yves Berthier since the end of the 80’s who added complementary conceptual tools as the tribological triplet, the accommodation mechanisms and the tribological circuit. The aim of this paper is to give a synthetic view of these concepts, which involves mechanical, material and physicochemical subjects. Concrete examples and case studies from various practical applications are given to illustrate the validity and the efficiency of such a phenomenological approach.