Antiwear Chemistry in Presence of ZDDP

Antiwear chemistry is related to the role of tribochemical reactions in controlling abrasive wear, adhesive wear as well as physical and mechanical properties of tribofilms. In the case of additives in boundary lubrication, three different chemical reactions have been found to be directly connected to mechanical response. First one is the digestion of hard metal oxides in the glassy tribofilm formed from the antiwear additives, thus combating with abrasive wear. Second reaction is the reaction of sulphur species with nascent metal surfaces, reducing adhesive wear between antagonist metal surfaces. The third reaction is an equilibrium one in the stressed tribofilm, leading to a change of mechanical properties of the tribofilm and explaining its smart behavior.