ANTIFRICTION AND ANTIWEAR CHARACTERISTICS OF MOLYBDENUM DITHIOPHOSPHATE IN ENGINE OILS

Antifriction and antiwear studies of lubricating oil compounded with e ngine oil additives such as petroleum calcium sulfonate (PCS) metal de tergents, polyisobutylene succinimide (PSI) ashless dispersant, zinc d ithiophosphate (ZnDTP) antioxidant and molybdenum dithiophosphate (MoD TP) using the four-ball machine (FBM) are reported. The results show t hat binary or ternary mixtures of MoDTP with ZnDTP, or ZnDTP and dipol yisobutylene succinimide (DPSI) obviously have beneficial effects on t he antifriction and antiwear properties of MoDTP. However, binary or t ernary mixtures of MoDTP with PCS, multipolyisobutylene succinimide (M PSI), or PCS and ZnDTP show different responses to the MoDTP antifrict ion and antiwear properties which depend upon different compositions. The molecular structures of the components of the MoDTP additive are a nalyzed by P-31-NMR spectroscopy.