Friction, wear and the role of additives in controlling them

Abstract

The laws of friction are described. Abrasive, adhesive, contact fatigue and corrosive wear mechanisms are explained. The tribological regime of boundary lubrication is discussed in the context of the Stribeck curve and surface film formation. Physical processes for surface film formation and their properties are examined for oxygen-, nitrogen-, sulphur-, phosphorus, boron, molybdenum-containing organic compounds and ZDDP in particular. ZDDP film formation is discussed in depth and the influence of dispersants described. Interactions between reduced ZDDP levels and molybdenum compounds to maintain wear protection and antioxidancy are considered for the requirements of lower SAPS formulations in future formulations. © 2010 Springer Science+Business Media B.V.