ELUCIDATION OF THE ACTION OF FUNCTIONAL GROUPS IN THE COEXISTING ASHLESS COMPOUNDS ON THE TRIBOFILM FORMATION AND FRICTION CHARACTERISTIC OF ZNDTP-FORMULATED LUBRICATING OILS

摘要

ZnDTP performs good antiwear or antiscuffing action by forming polyphosphate tribofilm [1-4]. Generally, various additives are formulated together with ZnDTP to fulfill the requirements for lubricants. Since recent energy-saving lubricants require good temperature-viscosity characteristics, formulation of good viscosity index improvers (VII) is important. Polyalkylmethacrylates (PMAs) possess superior temperature-viscosity characteristics, and its functionalized molecules perform reduction of the boundary friction by forming adsorbed molecular layers on the friction surface [5, 6]. In this study, influence of the coexisting additives, particularly ashless FMs (polar compounds) that improve friction reducing performance, on the performance of the ZnDTP-formulated oils was investigated. The effect of polar groups such as amino, hydroxyl, and carboxyl groups on the friction reducing performance and tribofilm formation of ZnDTP was studied to elucidate the action of different polar groups.