Tribology: Friction, Wear and Lubrication in Contact
A mechanism-based guide to real contact area, wear modes, lubrication regimes and surface design.
Contact occurs at asperities
Nominally flat surfaces touch through microscopic high points. The real contact area is much smaller than the apparent area, creating high local pressure and deformation.
Wear has mechanisms
Adhesive, abrasive, oxidative, erosive and fatigue wear produce different damage patterns. Correct diagnosis matters because a solution for one mechanism can worsen another.
Lubrication regimes
Boundary lubrication relies on surface films, mixed lubrication shares load between films and asperities, and full-film lubrication separates surfaces. Speed, viscosity, load and geometry determine the operating regime.
Materials work as pairs
Tribological performance belongs to the material pair plus environment, lubricant, roughness and motion. A material cannot be labelled wear-resistant in isolation.
Working rule
Begin with contact mechanics and the active wear mechanism before changing hardness, lubricant or coating.