9. Tribology

The main subjects of this chapter are the tribological system, friction, wear and lubrication. Regarding the tribological system essential information on structure, real contact geometry, tribological loads, operating and loss variables are provided. Concerning friction, the different friction types, states and mechanisms are discussed. In the sections on wear a lot of details on types and mechanisms of wear, wear profiles and the determination of wear and the average lifetime are introduced. The sections on lubrication contain relevant expositions on the lubrication states, like hydrodynamic, elastohydrodynamic, hydrostatic, mixed and boundary lubrication and lubrication with solid lubricants. Lubricants like mineral, synthetic and biodegradable oils and additives, lubricating greases and solid lubricants are also considered, as are the properties of lubricants, like the dependence of oil viscosity on temperature, pressure and shear rate, and the consistency of lubricating greases.