Chapter 1 - Introduction to Friction and Wear

Abstract

In the introductory section, a brief general description of the fundamentals of friction and wear is given. The chapter opens with the definitions of basic terms concerning friction, wear, and lubrication. The section on the mechanisms of friction includes the following topics: real area of contact, adhesion component of friction, ploughing component of friction, and deformation component of friction. The section on the mechanisms of friction is concluded with a consideration on the complexity of friction processes and the mechanisms of energy dissipation. The section on the mechanisms of wear includes the following topics: surface fatigue and delamination wear mechanisms, abrasive wear mechanisms, tribochemical wear mechanisms, and adhesive wear mechanisms. The section on the mechanisms of wear is concluded with a classification of wear phenomena. Finally, it is pointed out that friction and wear are not intrinsic material properties but depend on so many influencing factors that, in any given situation, the “whole tribological system” must be considered, including the following basic groups of parameters: (i) the “structure” of the tribological system, i.e. the material components of the system and the tribologically relevant properties of the system's components; (ii) the operating variables, including load (or stress), kinematics, temperature, operating duration, etc.; and (iii) the tribological interactions between the systems components. To assist the systematic analysis of relevant tribological parameters in a given friction and wear situation, a methodology and data sheet are outlined.